June at the JC Raulston Arboretum

This post is 6 of 12 of a series I’m doing this year reflecting back on some of my favorite plants from visiting the JC Raulston Arboretum while attending graduate school at NC State in Raleigh NC. Check back next month for more.

Ah, summer at the JC Raulston Arboretum. I loved how late I could be out at the garden photographing plants. And, in June I needed the extra time to fully appreciate the garden as there was so many plants in full bloom and offering interest in the garden. It had gotten warm enough that many plants were pushing toward their zenith as we reached the longest days of the year. Enjoy this look back at my time spent in this garden in June.

Woodies

Dichroa febrifuga is a somewhat obscure member of the hydrangea family that has pretty blue flowers in the summer. This cultivar 'Yamaguchi Narrow Leaf' has thinner leaves.

Cyrilla is a native shrub that tends to be underused. It tolerates wet areas well. Just note that it can be toxic to honey bees. While many botanists say that Cyrilla racemiflora is the only member in the genus, other scientists have split it into additional species. For example, this smaller leaved-form native to northern Florida is named Cyrilla parviflora.

In early summer new growth would emerge on Pinus wallichiana 'Zebrina'. I loved the two-tone banding.

I’m a sucker for big leaf hydrangeas. Hydrangea macrophylla 'Frau Reiko' was one of my favorites for its white-margined bracts.

And, in June Dr. Dennis Werner’s award-winning, dwarf, and mostly sterile Buddleja ‘Blue Chip’ would flower. It is a cute little shrub for small areas or garden border fronts.

Geophytes

The arboretum had a whole section devoted to geophytes, and in my opinion, June was one of the best times to see it. It had finally gotten warm enough to push many of these herbaceous plants into flower. Here we see a mass of the electric pink and yellow Gladiolus 'Flevo Kosmic'.

Eucomis, or pineapply lily, would also start blooming in earnest in June. Here ‘Sparkling Burgundy’ is just getting started. These inflorescences last long as cut flowers.

Another pineapple lily that I loved was Eucomis montana for its ivory white bracts that would fade to green. Did you know you can propagate Eucomis from leaf cuttings?

I admire a good color combo like this pairing of Dahlia 'Forncett Furnace' with the similarly colored Kniphofia uvaria 'Lola' in the back.

Here is a close up of Kniphofia uvaria 'Lola' since it’s not very visible above. Note that not all Kniphofia are geophytes, but it fit in well here.

A bee visits a flower of Dahlia 'Classic Elise' one evening. Even though they weren’t the large show flower forms, I appreciated seeing the dahlias at the arboretum just to know some could grow in the south.

I always enjoyed seeing the peach-colored flowers of Gladiolus dalenii ‘Boone’, a cultivar that was discovered in the North Carolina town of Boone. It also grows well here for me in Texas.

The soft white of Sinningia tubiflora with just a hint of pink in the tube was a welcome sight in the geophyte border.

And, I just had to throw this one in for kicks. While not at the arboretum, I photographed this fasciated lily (far right stem) leaving Kilgore Hall where the horticulture program is housed to head to the gardens one morning. Note how many flowers this specimen had compared to the others on the left.

Here’s a side view of the fasciation so you can see it better. Fasciation is a fascinating phenomenon where a genetic disorder or disease causes the stem to elongate along an axis. You often see it in flowers where the bloom will elongate in one direction, too.

HERBACEOUS Perennials

Many perennials achieved some serious height in June. One of my favorite daylilies is Hemerocallis 'Autumn Minaret'. I love it for its height, which allows one to plant it towards the back of a garden bed and still be enjoyed.

Eryngium also reach their pinnacle in summer. Here the very structural Eryngium eburneum is loaded with flowers, and the inflorescences were over my head.

Many people plant cardoons for their lovely winter foliage, but Cynara cardunculus also has flowers where the rays resemble glowing purple fiber-optic wires. Bees and other pollinators love these large Asteraceae blooms.

Vernonia lindheimeri is an ironweed I’ve been wanting to get my hands on for its velvety stems.

A really cool and somewhat rare plant at the arboretum was the endangered Baptisia arachnifera. This plant is native to two counties in Georgia and thrives in drier, sandier soils. It was quite at home here in the scree garden.

Panicum virgatum 'Cheyenne Sky' is an improved form of ‘Shenandoah’. To me it seemed to have more maroon color in the foliage earlier in the summer.

Ratibida pinnata is another underused native perennial. Sure, it can get a little tall, but I just love the rich yellow rays on this species.

One of my favorite color combination in the long border was this pairing of Echinacea purpurea 'Stewart's Pink', Panicum virgatum 'Shenandoah', and Monarda 'Violet Queen'.

I leave you with these two cool gradient shots that show the annuals in the trial garden. Here we have a warm gradient of Portulaca,…

… and here we fade from warm to cool for these Verbena.

A Little More Thyme

My thyme is in full bloom.  It’s one of the plants that I’ve had the longest in my life.  

My original start came in the early 2000’s from visiting Denise and Charles Berryhill’s herb weekend at their farm Briarwood Gardens right across the state line in Kentucky.  They were both generous in teaching me as a teenager about herbs and organic gardening, and I bought some of my first herb starts from them. The label said mother of thyme, but I’m still not 100% certain of its identity.

I planted the first little sprig of thyme in my little herb bed in the vegetable garden I had at my grandmother’s house.  It was welcomed amongst the mountain mint, sage, yarrow, and comfrey.  I watched it cover the ground and quickly form a dense woody mat. I enjoyed its little flowers it would don in early summer and the fragrance the leaves released with a simple brushing.

Time passed, an offer came for graduate school, and I moved to North Carolina.  I had to leave many of my plants behind, including the thyme. And, within a few years, the Bermuda grass that I had fought for almost a decade reclaimed the ground I had tended.  

After I got my teaching job in Texas, I wandered back to my old garden one Christmas.  I could still make out the worn down paths, but they were now covered by bleached turf mixed with sprigs of green yarrow that had survived my absence.  And, then it caught my eye.  A single sprig of thyme with its red winter cast.  I was ecstatic, as it had hung on this long as if waiting for me to return.  I dug it that day, and brought it back with me to Texas.  I nurtured it in a container, and soon it spilled over the edges and outgrew the pot.  

Once we moved to our log cabin, I planted it back into soil, and it took off once again.  I figured that being Texas it would die in the ground.  But, the plant’s survival surprised me again. This thyme grows during our wet spells, tolerates the hottest days next to black pavement, and shrugs off the cold winters.  I may occasionally loose a small patch, but the plant quickly works to fill the hole.  In June it comes into flower and attracts beneficial insects like bees and wasps.  And, with the first frost each leaf is outlined with a brilliant white, which forms an interesting pattern. Throughout the year, we like to use it chicken dishes as well as Poole’s Diner mashed potatoes with herb-scented cream.

In our kitchen garden it has grown into a dense layer of green that stops most weeds growing.  When needed, I rip off the edges and cram them into an open spot of soil where I want a good groundcover to help prevent erosion.  Life could always use some more thyme, especially one that’s been around for the majority of my time here on earth.

A wasp exits stage left from the thyme patch in our kitchen garden.

Philadelphia Flower Show 2021

Karen and I did a whirlwind trip through Philadelphia earlier this month to see the Philadelphia Flower Show the first day it opened to the public. I’m going to let the pictures and the captions below do most of the talking about our experience, but suffice it to say the show was an incredible experience. It was the first time I had ever been to the Philly Flower Show, and it was also the first time in the show’s 192 year existence that it was held outdoors. This floral spectacle is typically held in March, and that timing never fit well with my teaching schedule. While I don’t have previous times with which to compare this experience, I was amazed at the creativity and use of plant material in the exhibits. Many also commented on how rich the plants and designs glowed outdoors compared to the typical enclosed environment. Enjoy the photos!

Entering the Flower Show

The theme this year was habitat, not just for plants and nature, but also habitat for humans. At the entrance of the flower show we were greeted by life-size letters spelling out habitat.  The fronts were adorned with flowers and the backs were filled with colorful twigs. 

My good friend and Vice President of Public Horticulture at PHS Andrew Bunting joined us for a bit near the entrance to share more about the show. He said this Lysimachia atropurpurea 'Beaujolais', which appeared at Chelsea a few years ago, is used throughout this planting with Strobilanthes, Gomphrena, and Scabiosa further tying together the purple theme.

Behind the habitat letters was an incredible floral structure designed by Jeff Leatham, a celebrity florist who has done designs for the Kardashians.

Andrew told us that Jeff Leatham’s installation featured dried fern fronds and baby’s breath spray painted in electric pink and orange. 

Here you can see the color echo between the two exhibits.

The entrance of the flower show was rife with colorful banners.

The main sign you saw in the image above welcoming all to the flower shows was supported by these stacked planter boxes filled with colorful plants.

Andrew said that Bloombox was like the Amazon of plants in Philadelphia. They had an exhibit here showing their truck packed with plants for delivery.

Wambui Ippolito, Etherea

Best of show went to Wambui Ippolito for Etherea, a reimagining of the grassland habitat in her native east Africa.

We got the meet Wambui Ippolito, and she was so sweet and kind in talking with us.

Rusted metal, wood, and gravel were dominant hardscape elements among the rich flora.

Another shot of Wambui Ippolito’s Etherea showing a kettle of water and a wavy wooden bench.

Patrick Cullina, The Reinvention of Nature

I was delighted to know that my friend Patrick Cullina would be at the flower show with his The Reinvention of Nature. Pat is a wizard at imbuing ruins like the High Line and Bethlehem Steel with flora, and he did it again with this garden that featured reclaimed windows, rusted panels, and a water feature. The space was planted with towering Magnolia macrophylla and Taxodium ascendens (or the new mouthful name Taxodium distichum var. imbricarium). The floral exhibit in the distance added a nice color contrast.

Pat’s exhibit also featured a short back form of Dan Benarcik’s chairs.

Bees went wild over the magnolia flowers. And, I even loved how in this photo the Salvia flowers echo the magnolia’s color spots.

Donald Pell Gardens, The Wild Garden

I loved this dining area that rested on a stone plinth within a glade of native trees for Donald Pell Garden’s The Wild Garden.

This exhibit also featured cool wood burned signs that described the plants like you see here with this herbaceous matrix.

Arrange, Floral, & Event Design, Habitats of the North American Cryptids

Some of the exhibits we would learn were more floral themed. I thought this installation that focused on the imagined habitats of the North America cryptids like chupacabra, the Jersey Devil, Sasquatch, and moth man was really clever.

Moth man’s cocoon was made out of various knick-knacks and planted with the color echoing Ricinus and Coleus.

American Institute of Floral Designers, Habitat Reclaimed

Habitat Reclaimed by the American Institute of Floral Designers featured a house frame taken over by various floral accoutrements.

Karen loved these foliage pillows sitting on a bench.

Another side of the house shows more of the floral arrangements that have reclaimed this space.

And, inside the house was a floral take on van Gogh’s Starry Night.

Treeline Designz, Dancing with Nature

Treeline Designz Dancing with Nature featured the use of bamboo, not only in the structure but also as a featured plant material.

Andrew commented that it was fun watching them assemble this exhibit with trying to get these ball and burlap bamboos through the grid above.

The inside of a few of the cut bamboo were painted to help draw you into the display.

Nomad Studio, Kokedama Forest

One of my favorite installations was Kokedama Forest by Nomad Studio that was designed to highlight soil microflora and how this habitat is a network that supports plants and animals. Standing outside you can easily see the frame…

…but inside, it is harder to see this underground habitat with all the plants. I also loved how they created this amphitheater effect where walking through we see and enjoy the plants because of this underlying soil network. This photo was a bit of a challenge to take because there was a line of about 20 people to see the exhibit.

Another shot of the native trees growing as kokedama, moss-covered balls of soil that support a plant.

Here is a close up of the kokedama so you can better see the supporting balls.

Jennifer Designs, Nature’s Resilience

This exhibit by Jennifer Designs showcased the resilence of nature, and the plight of the Australian outback with the wildfires they recently faced.

Petit Jardin en Ville, Beauté et Générosité

I loved the quaintness of these European-themed courtyards for Petit Jardin en Ville’s Beauté et Générosité. The first featured shrubs and trees in a formal planting.

The second courtyard had a water feature and more herbaceous plants.

And, the third was an edible garden complete with dining area, planter boxes, and cold frame wires.

WRT, Painted Threats

WRT did this cool exhibit where they painted invasive species like non-native phragmites a bright pink to show them entering native habitats. I also loved how educational their install was with the signage.

Don’t you just love this modern take on a bird house?

Native habitat prior to invasive species entering features a rich wetland flora. It is amazing to me that people can build a wetland in two-weeks!

WISH Unlimited, Faraway, So Close

WISH Unlimited showed how we have been living in the pandemic. A giant terrarium features Araucaria, succulents and tropicals, and of course a microphone to illustrate how technology kept us connected in our isolation.

PHS Gardeners Green

The Gardeners Green was a place that attendees could come learn more about horticultural practices and the Pennsylvania Horticultural Society. It was based on public commons that once dotted the city. Aren’t those espaliered fruit trees awesome?

At the Gardeners Green, they did a demo of willow weaving, a natural approach to building garden edging and fencing.

They even had beehives in the Gardeners Green!

STUDENT EXHIBITS

I was delighted to see some student entries. In one section were several designs that offered a new way of thinking about hell strips by calling them heaven strips. The Evergreens of New Jersey planted this minute paradise.

And, here was Covid Confinements, an installation by the Horticulture Academy of Abraham Lincoln High School that showed how teenagers lived during the pandemic.

Hudson Valley Seed Company

I have to give a shoutout to Hudson Valley Seed Company and their brilliant seed packets. Many packets feature an artist’s handiwork.

Hudson Valley Seed Company also had some educational displays in their tent showing more about the artist and the plant.

I wish we had more time at the show, but an afternoon flight beckoned us home. But, from this morning visit, I know I can’t wait to get back to Philadelphia again, hopefully at yet another time the flower show is being held!

Claude Monet, Plantsman and Painter

I didn't know much about Monet before I went to France.  I knew he was a painter, that he had a garden, and that he had a bridge in his garden where he had painted water lilies. 

But, after visiting his garden in Giverny, I feel so connected with him and his work. I learned that he was a horticulturist. In Monet’s Passion, Elizabeth Murray shared that Monet wrote that his garden was his “greatest form of art” and “I perhaps owe having become a painter to flowers.” He sounds like my kind of guy! I also came to really know impressionism, this style of painting where instead of focusing on details you capture a snapshot view of a landscape at a time.

This map should provide you with an overall impression of Monet’s garden. To the right is the water garden, and in the middle is the Clos Normand. The hoops within this garden frame the Grand Allée and frame a primary axis that runs from the house into the water garden. The light blue are the streets, not waterways.

The trip was part of a study abroad expedition that I helped lead in 2016 with our students. We arrived at his garden in Giverny on a cloudy day that teased rain. Our guide Leif enriched the experience during our tour. He shared with us that Monet was one of the artists that started the impressionism movement; even the phrase impressionism comes from Monet's painting Impression, Sunrise.  This method became popular because of two inventions—photography and paint in tubes.  The former inspired people to no longer desire to capture every detail in a painting since they had the technology to do that in an instant; the latter allowed people to leave their workshops and painting studios, head to the countryside, and paint plein air instead of what they saw on a table.

The Water Garden

We first saw the water garden, a later addition for Monet that he acquired after he bought the house and garden property. He designed the two-acre water garden to be a mirror that would reflect flowers, clouds, trees, or whatever nature could offer. And, to fill the garden with water, he had to actually convince the locals to divert water from a stream that fed into the nearby River Epte. Monet also offered to pave the barren road that ran between his house and water garden for the community with gravel to reduce the amount of dust on the plants.

Eventually, his garden grew to the point he hired gardeners to care for the place. The waterlily gardener had special tasks. When Monet was painting waterlilies, this individual had to come out early in the morning and remove the pond of any debris and any past prime flowers.

Monet’s two-acre waterlily garden was lush and green but too early for many waterlilies to be blooming. Note how the water reflects trees, sky, and color on the shore.

Here is a glance the other direction at the bridge that he painted.

And, here is a photo for comparison I took a few days later from Musee d'Orsay in Paris of Le Bassin Aux Nymphéas, harmonie rose (water lily basin, pink harmony). I was so touched by impressionism that I used part of a free day to go see more of Monet’s paintings.

Lupinus and Digitalis frame this view of the smaller bridge at the other end of the water garden.

A glance up one of the streams that feeds the water garden. Laburnum and Rhododendron punctuate the edges with color.

Clos Normand and Grand Allée

From the water garden we then crossed over to the main garden called the Clos Normand. This part of the garden was designed with beds of plants that radiated out from the house. At first, Monet cared for and tended to his garden throughout the day. Even his children had to haul buckets from the well to water the garden. But, eventually Monet’s popularity as an artist would allow him to hire a five-person gardening staff.

This space was an experimental canvas where he was able to play with the way light interacted with the different plants. Monet went out to paint at different times to capture the ambiance he saw.  He painted at breakfast, ate lunch, then went back out to paint in the afternoon.  Monet had to paint quickly because he wanted to capture a point in time.  Thus, his canvases should be viewed at a distance because it's broad brush strokes, just like how we should see a garden instead of focusing on every individual plant.

The Grand Allée in its spring attire looking toward Monet’s house.

A close up of one side of the allée planted heavily with a white form of Hesperis matronalis.

Next to the Grand Allée was the start of this series of straight paths that were planted with herbaceous plants. Larger roses or trees were a little further off the pathway.

This pathway was planted with blue Iris and set to line up perfectly with the window in the background, no doubt to create an interesting vista from within the house as well.

This path was a little further away from the Grand Allée and featured more color and larger trees framing it on either side.

From this cross image of the Clos Normand you really can’t make out the pathways. Instead it is a myriad of colors. Note the absence of much texture. Monet is said to have focused on color instead of having much winter interest.

In parts of the Clos Normand garden, espaliers framed the plantings. I loved this green approach to edging.

Beyond the espaliered fence was a lawn where they had allowed the bulb foliage to remain and die naturally to maximize flowers for next year.

Near Monet’s house, chickens were even given a place to roam.

COLOR COMBINATIONS

The garden was rife with color pairings. His garden was different from the typical French style of manicured shrubs and tapestry plantings because it was so saturated with color. And, even 100 years later his passion as a colorist lives on in this place with the combinations created by the gardeners today.

A warm color scheme of azaleas and various other herbaceous plants livens up the waterlily garden.

Here Hesperis and Digitalis play off a purple pairing.

In parts of the Clos Normand garden, the gardeners created these color gradients. This one shifts from yellow in the foreground through white, red, orange, and pink as you look closer and closer toward the house.

From a slightly different angle, you can see the blocks of colors.

Who says you can’t pair orange and pink… and a multitude of other colors!

And, I just had to share one of my favorite plants, Nectaroscordum siculum. Their rosy petals erupt and combine well with so many different flowers.

I love the chandelier architecture of this Nectaroscordum siculum flower and so wish we could grow it in Texas.

Up near the house, I admired this Erysimum flower choice to match the color of the paint.

GIVERNY

After visiting the garden, we walked the quaint streets of Giverny to make our way to Hotel Baudy for lunch. This establishment became famous for the mingling of artists that visited to learn from Monet as the the town became know for its hub of impressionism.

We had a delicious lunch at Hotel Baudy, a meeting place for artists back in Monet’s day.

And, of course, I just HAD to try their creme brulee.

After lunch we walked the streets admiring the lovely town that Monet used to call home. Here a small courtyard in Giverny is flanked by Iris and Vitis.

Even the signs coordinate with the flower color on this Salvia.

Throughout Giverny I noticed the subtle pairings of colors, like this Salvia officinalis ‘Tricolor’ with the mauve petals of a clambering Clematis.

And, at the impressionism museum, color combinations continued like this planting that screams gold and orange.

While we didn’t have time to go through the Museum of Impressionisms, we did walk the grounds a bit. I liked the poppies here, perhaps an allude to Monet’s The Poppy Field?

A modern take on one of Monet’s paintings as we crossed the road to head back. Monet was able to enrich our world with art because plants enriched his.

We left Giverny and Monet’s garden filled with the beauty we had seen. I wish we could have stayed longer, but the schedule held more riches for the day in the promise of seeing Le Jardin Plume.

It still amazes me that Monet attributed his origins of great art to flowers. May we all strive to find such inspiration in the plants around us just like Monet did.

May at the JC Raulston Arboretum

I loved May in graduate school at North Carolina State University. Being free of homework and tests allowed me more time to focus on graduate work and research. And, in the evenings I had even more time to go visit the JC Raulston Arboretum. May was the first month where the garden didn’t feel like it was trying to decide should it be spring or winter. Warmth had settled in and the plants responded beautifully. Enjoy this reflective plant list of many of my favorites of mid-spring.

THE WOODIES

Hands down one of my favorite shrubs of all time is Corylopsis spicata 'Golden Spring'. It has beautiful late winter flowers, but to me the best show is when the yellow foliage emerges with hints of pink in the new growth.

The parade of magnolias continued in May with many of the evergreen species flowering. I was always delighted to search for the hidden flowers amongst the strap-like leaves of Magnolia yuyuanensis.

I can smell a banana shrub from 100 feet away. Usually the flowers are white, but this variety Magnolia figo var. crassipes has intense purpling in the tepals.

May is also one of my favorite times of the year to see variegation. Most of the leaves have emerged and started growing, and they aren’t burned yet from the heat of the summer. While there are a few variegated redbuds, Cercis canadensis 'Floating Clouds' was one of the best for holding color into the summer.

Deutzia get a bad wrap for being scraggly shrubs that only flower for a few weeks each year, but I still love them for their pearl-shape buds and beautiful chains of flowers. This variegated Deutzia crenata 'Summer Snow' helps extend the season with its white speckled green foliage.

Wowzers, even if this Hydrangea paniculata 'Shikoku Flash' never flowered, I’d still be happy with this spectacular cream mottling.

May is the month that some of the first fruits of the year ripen after late winter and early spring pollination. Here the native Amelanchier ×grandiflora 'Silver Fountain' is loaded with serviceberries ripe for the picking.

Our native Wisteria are often flowering in May. Seeing them reminds me of the plant at my grandmother’s house. This native Wisteria macrostachya 'Aunt Dee' was the first hint that maybe the plant that my grandmother raised wasn’t an exotic but a form of Kentucky wisteria. The seeds that the plant developed a month or so later were a second clue.

I’m not much of a rose person, but the pink stamen filaments on this Rosa 'Meiguimov' The Charlatan® really caught my eye.

Clematis 'Princess Diana' clambers through Cotinus coggygria 'Ancot' Golden Spirit for a striking combination.

I swooned the first time I saw the patina foliage of Cotinus coggygria 'Old Fashioned'. Isn’t it rich?

Oakleaf hydrangea are one of my favorite shrubs, and I was so delighted to discover this Hydrangea quercifolia ‘Turkey Heaven’ at the arboretum. The massive flowers hold up a bit better than ‘Harmony’, another cultivar with large blooms.

A close up of the billowing inflorescences of Hydrangea quercifolia ‘Turkey Heaven’

Now we are getting into some of the subshrubs. Leucosceptrum japonicum 'Golden Angel' has some woody characteristics, but most people treat this Japanese shrub mint as a perennial. The vibrant foliage certainly brightens a dark spot.

Lavandula stoechas is one of the few lavenders that we can grow in the deep south. Seeing how well it performed in humid Raleigh lent me to trying it in Texas. It has performed well here, minus dying back from the below 0F temperatures we had this past February.

I always loved the long border designed by Edith Eddleman and all the color combinations therein. Here Phlomis fruticosa contrasts nicely with the blues of Tradescantia, Amsonia, and Nepeta.

I’ve always loved Phlomis fruticosa for its vibrant yellow bilabiate flowers. You can also see its pubscent foliage here.

THE HERBACEOUS

I was surprised to see Digitalis growing well in Raleigh early in my grad school days. I thought they were more of a northern plant, but it seems getting them started in the fall and then overwintering them works.

I’m a sucker for poppies. I loved this cute little Papaver pilosum with its salmony colored petals.

Yes, I know Paeonia 'Bartzella' is a hybrid between a tree peony and an herbaceous peony, but I stuck it here in the herbaceous section because I feel most people treat it like a perennial. And, wow, does it have incredible yellow flowers. Seeing a peony thrive in the south was certainly a welcome sight.

And, here’s another peony doing well in zone 7b/8a! This is Paeonia lactiflora, the straight species that we know has resulted in many cultivar selections. I admired its blushed white petals and the simplicity of the single flower.

Romneya coulteri was always an interesting spring flowering plant in the scree garden. I liked the glaucous blue foliage that held the white and yellow flowers, and it really popped against the faded wood wall. I vaguely remember it spreading via runners or roots.

A close up of the beautiful flowers of Romneya coulteri

And, I can’t feature some of my favorite May plants from the arboretum without mentioning Asclepias tuberosa. Seeing it thriving here in the scree garden certainly provided some subconscious ideas about growing plants in gravel.

May was also the month that the tropicals really started growing again. I knew this very hardy Hippeastrum ×johnsonii from Tennessee. My parents have it in our front yard. Here it pops against the dark foliage of a Dahlia in the geophyte garden.

Another beautiful red flowering geophyte was the interesting Sprekelia formosissima. Don’t you just love that flower architecture? Native to Mexico, this plant is somewhat tender but worth finding a spot for in the garden.

I loved the two-tone red and yellow of Canna patens. The narrow petals are not as gaudy as the hybrids on this species.

Here is a nice mass planting of Eremurus 'Lemon Meringue', a geophyte I discovered during my visits to the arboretum. The flowers last for several weeks.

Scarlet Penstemon

Red is one of my favorite colors. I’ve joked since a kid that I love it so much that it is part of my name, Jared. I even love variations of the hue—scarlet, coral, vermillion, crimson, cherry, garnet, and the list goes on.

Red is a bit of an unusual color to have on native flowers. Think about it. You can probably count on your fingers and maybe toes native southeastern wildflowers that feature this intense warm color. Most flowers that are not wind pollinated seem to have purple, yellow, pink, or white adorning their petals. But, red flowers are a bit rarer and likely evolved for the hummingbird pollination syndrome since birds can perceive this hue better.

I was delighted after I moved to Texas to add another red flower to my plant palette, scarlet penstemon. I first saw Penstemon murrayanus in a garden bed in Nacogdoches. I was so intrigued with its perfoliate leaves on the inflorescence that wrap all the way around the stem. The flowers looked like they were rising out of little teal green platters.

Perfoliate leaves on Penstemon murrayanus are an intriguing morphological feature. It is so neat how they wrap around the stem.

After buying our house, I wanted to add scarlet penstemon to my plantings. On the road to town one day I discovered some plants growing right under a power line back off the road. I was surprised to see this species thriving in sandy grit amongst Yucca. But, this site helped me understand the conditions where it grows.

A small population of Penstemon murrayanus growing along the roadside in Nacogdoches county.

These plants I found provided a source of genetics for me to get my plants started. I collected seed after the seed capsules dried, but I learned that getting the seed to germinate is a challenge. The first year, I sowed seed at the start of winter to allow them to naturally stratify, but I only had two seedlings emerge out of the batch. Fortunately, they flower the second year after their attractive glaucous green foliage bulks up for the first growing season. While I love the height the plants get, they are also see through, so they can be planted at the front or the back of the bed and not impede the view. Their opacity allows me to sit on my porch and easily watch Ruby-throated Hummingbirds dot from plant to plant.

I like how I can see through the inflorescences of Penstemon murrayanus.

The purple in the stem here created a great color echo with the Prunella vulgaris behind.

I should add that I have had my challenges growing it. The foliage and even sometimes an inflorescence will die back to the ground due to a fungal disease. My guess is that my soil is more dense than the sandy soil where I found this species and holds more water. This issue seems to be a common one with Penstemon in the wetter parts of the country.

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Going back to the challenge of getting new plants started, I was able to collect enough seed off my plants this year that my graduate student Zy Tippins was able to see if germination could be enhanced on Penstemon murrayanus. Her master’s thesis has been focusing on the use of gibberellic acid and liquid smoke to improve seed germination of native perennial seed. Gibberellic acid is a plant hormone that promotes germination. Liquid smoke can contain karrakins, another germination promoting hormone. There’s research that demonstrates after a fire passes through an ecosystem that karrakins are produced and help increase germination of some plant species. While gibberellic acid can be a bit of a challenge for home owners to acquire, smoke water is readily available from grocery stores. Zy was seeing if smoke water could be used with or without gibberellic acid to increase germination.

As you can see from her research below, seed that only received water and no stratification had 9% germination; stratifying seed for three months increased germination to 20%. But, seeds that had smoke water and three months of stratification had 46% germination! That means with using smoke water and then moist chilling the seeds in the fridge you can almost quadruple seed germination over the control. This data was some of the most exciting from her work. She’s finishing up her thesis this summer, so I’ll definitely post the link later if you want to learn more about her research.

Penstemon murrayanus seeds that were treated with a dilute smoke water solution and then stratified for three months had better germination (46%) compared to the non-stratified (9%) and stratified (20%) control. Thanks to my graduate student Zy Tippins for sharing this slide with me.

My hope is that with her research Penstemon murrayanus will become more available in the trade now that we better understand its germination requirements. Yes, it is an obscure perennial, but it certainly deserves wider use in our gardens.

Dipping into Baptisia Again

I’ve never seen Baptisia australis in the wild, even though it is one of my favorite perennials. I wrote a few weeks ago that I had encountered Baptisia alba, Baptisia sphaerocarpa, and Baptisia bracteata and that I hoped to add Baptisia australis to my life list, soon. 

I decided this spring would be a good time to search for this species. I reached out to colleagues who were familiar with the northeast Texas region since that is the nearest place to me that this blue wild indigo grows.  My friend Sonnia introduced me over the internet to Carol Clark, a naturalist who is quite keen on the flora and fauna of north Texas.  After Carol and I conversed for a bit, she put together a wonderful itinerary for seeing Baptisia in the wild.

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For our first stop on the Baptisia tour, Karen and I arrived to Clymer Meadow around 10:30 am.  This 1400-acre Nature Conservancy site is a virgin prairie north of Dallas that has never been plowed and only used as forage for livestock.  Many consider it an excellent preserved example of the Blackland Prairie that once covered much of the middle of North America.

Clymer Meadow is a collection of various tracks of land that is managed by The Nature Conservancy.

We parked at the top of a hill near a grove of trees where we could survey the acres of grassland that surrounded us under an ash-colored sky.  Here, I met Carol for the first time, her friend Stephanie Jennings who works at the Heard Museum, and Brandon Belcher who stewards the Clymer Meadow with The Nature Conservancy. 

We walked down the hillside, and Brandon showed us a population of 50–100 Baptisia australis that straddled a mowed section of pipeline.  I was curious to see their habit in the wild as well as the different colors, and I was delighted to see many variations on the theme of blue.  Slivers of cobalt, periwinkle, purple, indigo, and chambray rose above the mosaic of last year’s brown duff.  In the clearing Castilleja purpurea also blazed magenta against the unkempt, wild grassland.  It was such a great analogous color combination that I wish I could recreate in a garden; however, the Castilleja is a hemi-parasite; thus, it feeds some off the roots of neighboring plants and is difficult to grow in cultivation.

Baptisia erupt from the tapestry that is last year’s tan threads and this year’s green flush.

The pink you saw in the left corner of the image above was Castilleja purpurea, purple Indian paintbrush. This particular clump was had richer purpling.

A smoky purple selection of Baptisia

Castilleja and Baptisia made a most excellent pairing.

My mind drifted back from the Castilleja to the Baptisia.  They were much shorter than I expected and shorter than the types that I encountered in gardens.  This form was Baptisia australis var. minor, a more compact variety that many love to use in naturalistic design for its dense stem mound habit.  Carol and Brandon noted they were usually a little taller and attributed their diminutive demeanor to the cooler spring and commented that they just hadn’t fully expanded yet. 

A rich purple form of Baptisia australis var. minor. Notice how the plants barely rise above the fray.

Brandon commented on how other plants were late, too.  In the matrix of foliage below we saw Manfreda, Eryngium, and Silphium short and waiting on their moment later in the year.  Even Nemastylis geminiflora wasn’t in flower quite yet. 

After sampling the variations in the Baptisia population, we walked back up the hill.  Brandon mentioned that at Clymer Meadow, a fascinating soil phenomenon called can be observed.  He took us just beyond the tree grove where we parked to an open spot in the grassland.  He had me stand on the top of an elevated soil spot, and he stood a few feet away in a wet depression called a gilgai.  On flat ground we had been looking eye-to-eye, but now there was at least a two foot difference in our height. 

Here I’m looking down on Brandon from my small hill. In the lower left you can see a wet pocket, or gilgai. These depressions fill with water while the higher spots stay dry and provide habitat for grasses like Pancium, which you can see its tan ribbons scattered about in this image.

He explained these small pools and small hills develop from soil wet/dry cycles.  When the soil dries, it cracks open and sediment falls in.  Then, when it rehydrates during the cooler seasons, the soil expands and the sediment gets pushed upward.  This process then repeats over years and years until it creates a vast honeycomb appearance across the landscape. This soil pattern is also called gilgai, just like the little pools of water. 

He said that this micro-typography creates some interesting habitats for plants because within a few short feet you go from hydric conditions where Juncus grows to more mesic/xeric conditions where Pancium can be found.  Brandon commented that the small pools in the depressions can be wet all the way into summer and provide a home for frogs and other critters. 

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We left Brandon at Clymer Meadow, and the rest of us headed to Pioneer Park next to eat a quick sack lunch and see if we could find Baptisia there.  We did not, but while walking through the prairie and being serenaded by Dickcissels, I was able to see Callirhoe alcaeoides for the first time in the wild.  This light poppy mallow is a delightful perennial that deserves wider use. 

At first I thought these Callirhoe alcaeoides were an Oenothera from a distance. Was I surprised to see this species in the wild!

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Next we went to the home of one of Carol’s friends who had a five-acre prairie in her backyard.  Pulling in the driveway, I was delighted to again see Baptisia in bloom, and there were more here in this front part than we saw at Clymer Meadow.  Carol commented that this section wasn’t the best, and it would better behind the house.  She was right.  Behind their house was long grassland, and at the very back were hundreds of Baptisia.  Again, there was a myriad of colors of blue and purple here.  We found some very floriferous forms as well as a compact form that had already finished flowering.  She said they never burned it, but they would mow it each year. 

Hundreds of Baptisia australis var. minor bloom in this backyard prairie.

Here’s another section where you can see the variations of blue and purple flowers.

Here was a form with a rather dense inflorescence, packed with flowers.

We found this compact, early form quite interesting. It finished flowering a week or two ago, while all the other plants around were in their full splendor.

I quite liked this periwinkle color on this Baptisia.

I shared with Carol and Stephanie how I learned in writing my last post on Baptisia that bees will move up the inflorescence from lower, nectar-filled pistillate flowers…

…to more pollen heavy staminate flowers nearer the top. Then, they hopefully will take that fresh pollen to the next flower and repeat the process. It helped to have a bee demonstrating this pollination syndrome as I described it. :-)

 Mixed in with the Baptisia were other great natives like Linum berlandieri, Penstemon cobaea, and Amsonia ciliata var. texana. 

For all the blues and purples we saw today, it was nice to have the contrasting yellow and orange in Linum berlandieri at this site.

This site was also my first encounter with Penstemon cobaea in the wild. Don’t you just love those big honkin’ flowers?

I was intrigued by Amsonia ciliata var. texana. They formed these large clonal colonies, something I was unfamiliar with seeing Amsonia do.

The flowers of Amsonia ciliata var. texana had a surprising sweet fragrance with echoes of vanilla.

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It was getting later in the afternoon, and Carol suggested that as a last stop we should go check out a spot north of us where they were expanding the road and she had heard from a friend some Baptisia were in the construction area.  We found it and pulled off to survey the population.

The site where the road is being expanded cuts right through a population of Baptisia.

I climbed out of my truck, my eyes saw it, and I exclaimed, “A WHITE ONE!!!” 

GASP!!! Jaw drop. Wowzers.

We had seen hundreds of Baptisia all day, and yet here in this construction area was a white Baptisia australis var. minor.  We rescued this specimen as well as a few other plants that had been run over and were in the kill zone before we parted ways and headed home.

Overall, it was a great day learning more about Baptisia australis var. minor in the wild and making new plant friends. We hope that some of the forms we saw can be propagated. Gardens need more Baptisia, and it is even better knowing exactly where they grow and where they originated.

Sweet on Sweet Peas

I’ve had that new plant feeling all over again this spring. You know that feeling where you try and try to grow something but fail and fail. But, then something clicks, and you’re off to the races. For me the species that has elicited these emotions is Lathyrus odoratus, the sweet pea.

I used to look reluctantly at people who held fistfuls of sweet pea flowers, thinking that I would never have that. Some of you readers may be surprised to hear that I’ve had challenges with sweet peas since they are relatively easy to grow. But, here in the deep south, they are more challenging. Success with them has eluded me when I have tried them in previous springs. They would quickly peter out from the heat with barely a bloom or two emerging.

So, what changed this spring? My friend Caleb Melchior suggested sowing the seed in the fall to overwinter. On November 1, I soaked seed overnight, and direct sowed them the next day. I was delighted to see their green threads emerge from the soil. I mulched them with aged leaf mold and staked them with nylon netting using this trellising technique I saw from Neversink Farm. They slowly grew over the winter, somewhat creeping along the ground as if searching for an upright to climb even though the trellis was above them. I was surprised when they survived the -6F we experienced in mid-February, no doubt due to the insulation from the heavy snow that came with the cold.

Soon after they began to produce rising shoots. I took Matt Mattus’s advice and pinched them to one shoot per plant to help concentrate the resources into fewer smaller blooms. And, did that practice pay off because my plants began producing giant flowers on foot-long peduncles.

‘Nimbus’ started flowering first with a single deep purple and white flower in early April. I cherished that first little flower. I took it to class, showed it off to students, and described my challenges with this species. Then there were three flowers, and then ten, and now, I chuckle because I’ve probably harvested over a hundred inflorescences off my ‘Nimbus’ plants.

‘Mars’ and ‘Wiltshire Ripple’ followed, and now the eight varieties that I tried this year are in full bloom. From my writings on Baptisia, you readers already know I’m keen on the papilionaceous flowers of the Fabaceae family. But, I could never imagine the beautiful colors of these sweet peas. And, the speckling, ah, to die for! It is amazing to see these dots and stripes that those in the know call flakes on cultivars like ‘Mars’ and ‘Wiltshire Ripple’. I had heard sweet peas were fragrant, but I never imagined how a bouquet could perfume a room. I find myself bringing fresh flowers into the house a couple times a week. Of course I should add that the seeds are poisonous, but my plants never get a chance to make a pod as I keep the flowers clipped.

The success makes me feel like a kid again, giddy with excitement on something that has eluded me for so long. I’m hooked on sweet peas, and you can bet I’ll be growing even more next year.

‘Nimbus’ was my first sweet pea to flower this spring, and it has been an incredibly prolific flowering cultivar.

‘Mars’ started flowering shortly after ‘Nimbus’. I do love the red flakes on this form.

‘Wiltshire Ripple’ has this lovely wine color to the petals.

‘Promise’ offers two tones, a pink banner and white wings.

The color of ‘Carlotta’ reminds me of the petal color on Gladiolus communis var. byzantinus. They also bloom at the same time here in east Texas. Perhaps a possible combination for the future?

Coral is one of my favorite colors, and when ‘Florencecourt’ started blooming, I swooned.

I have been impressed with the size of the pale pink ‘Anniversary’.

I only had a couple ‘North Shore’ germinate. Its variable blue-to-purple flowers are welcome in the dominant red-to-pink cultivar assemblage I planted this year.

One morning’s sweet pea cuttings show the analogous color scheme I unintentionally planted this year. The more flowers you see, the more prolific and longer blooming that cultivar has been. Left to right back row ‘Mars’, ‘Nimbus’, ‘Wiltshire Ripple’; middle ‘North Shore’, ‘Promise’, and ‘Florencecourt’; and front ‘Anniversary’ and ‘Carlotta’.

April at the JC Raulston Arboretum

This post is 4 of 12 of a series I’m doing this year reflecting back on some of my favorite plants from visiting the JC Raulston Arboretum while attending graduate school at NC State in Raleigh NC. Check back next month for more.

This week was our last week of classes on campus. The end of the semester is always hectic, but it was even more so this year with the stress of the pandemic and the impact on students.

I recall back in graduate school that towards the end of the semester when things got crazy, I found myself wanting to go to the JC Raulston Arboretum to experience the plants and nature. I would go on long walks there enjoying the flowers and plant life often as a break between projects, papers, and research. And, April is certainly a good time to explore a garden as it erupts with color. It always amazed me that even though March felt full of color, April could always beat it.

April was also the first time I ever visited the JC Raulston Arboretum when I was interviewing for my graduate school position, so this month certainly holds a special place in my heart when visiting. Enjoy these photos of some of my favorite plants from the arboretum in April. I hope they inspire you to try a few new ones in your garden.

While many cherry trees struggle in the southeast, I delighted at the size of this Prunus serrulata ‘Ukon’ and its semi-double, creamy green colored flower petals. The cultivar name means turmeric.

The parade of Magnolia continued into early April at the arboretum. Magnolia × loebneri 'Leonard Messel' is beloved by many for its color and frost tolerant flowers.

Magnolia ‘Coral Lake’ is hands down one of my top five favorite Magnolia cultivars. I just love the two-tone yellow and pink color.

Another shot of Magnolia ‘Coral Lake’. It was fun watching it become a small-statured tree during my time in Raleigh.

I can’t wait to acquire some Magnolia ‘Lois’ for planting around our log cabin. Many consider this selection one of the best yellows because it is more compact and later flowering; thus, it tends to miss the freezes.

How cool is this plant!?! I was amazed when I first encountered Cornus florida subsp. urbiniana, a form from the mountains of Mexico that has fused bracts. It was one I even remembered from my first ever visit to the arboretum.

One of my last years in graduate school I discovered this Cornus florida ‘Plena’ in a hidden corner of the arboretum. This cultivar features multiple bracts. I was amazed that after being there five years and walking all over there were still plants I hadn’t noticed yet.

Another favorite dogwood was the dwarf Cornus florida ‘Suwannee Squat’. Normally I’m looking up at dogwood flowers, but with this selection, I looked down on them.

Sinojackia xylocarpa 'La Grima' is a lovely upright selection of jack tree. Doesn’t it have such a nice vase shape?

I loved standing under Sinojackia xylocarpa 'La Grima' when it was in full flower and admiring the star-shaped flowers.

Here’s one this Tennessee native loves, Cercis canadensis ‘Tennessee Pink’! The flowers have such a rich pink color, and this redbud has good vigor.

One can’t talk about the plants at the JC Raulston Arboretum and not mention the incredible development of Calycanthus × raulstonii 'Hartlage Wine'. A cross between Calycanthus floridus and Calycanthus chinensis, this cross by Richard Hartlage has incredible vigor. The flowers are larger than either parent, and I’ve heard of some plants growing over 20 feet tall.

In the old rose garden, I always admired the southern classic Rosa banksiae 'Lutea' or Lady Banks rose. Amazingly, ours on campus this year was badly burned by the sub-zero temperatures we experienced.

Isn’t this color on Rhododendron × bakeri ‘Cylo Red’ incredible? I don’t think I’ve ever seen such an intense pink on a native azalea before.

Oakleaf hydrangeas are one of my favorite, if not my most favorite, shrubs. The JC Raulston Arboretum was one of the first places I saw the gold leaf Hydrangea quercifolia ‘Little Honey’. I would end up having one of these in my apartment patio container collection for a few years after seeing it in the arboretum.

It might not look like much, but Croton alabamensis is a durable and tough shrub for the southeast. It is rare, though, and only occurs in a few counties in Alabama and Texas.

A close up of the inconspicuous flowers of Croton alabamensis

Ungnadia speciosa is a wonderful and underused native large shrub/large tree. It is called Mexican buckeye because these purple, red-bud like flowers produce capsules that produce marble-sized seed in the fall.

A close up of the flowers of Ungnadia speciosa

Many Acer palmatum have incredible spring foliage color. Don’t you just love the red-tinged margins on the gold foliage of Acer palmatum 'Orange Dream'?

I enjoy Deutzia, even though they can look a little scraggly later in the year. Most Deutzia I had seen had white flowers, but I loved the pink highlights on Deutzia scabra 'Pink Minor'.

Exochorda ‘Blizzard’ is an improved selection bred by Tom Ranney. The flowers on this pearlbush are double the size of other Exochorda cultivars.

Growing up, we had black locust on fence rows, and their white flowers in April were always a sign that spring had arrived. I loved discovering this pink form of Robinia × margaretta 'Pink Cascade'.

If you didn’t get enough Baptisia last week, here’s a shot of Baptisia alba var. alba. Again, don’t you just love the smoky purple stems?

My mom had this exact planting combination back at our house in Tennessee, a carpet of Athyrium niponicum var. pictum under Polygonatum odoratum 'Variegatum'. It is such a great color combination that will really last all growing season for much of the country.

Pulsatilla were a new species I learned from my visits to the arboretum, and I grew to love their feathery seed heads. This is Pulsatilla cernua, a species native to Asia. I learned something fascinating researching this post. Scientists have noted that the flowers go from upright to pendulous to upright again over the week and a half that the flowers are in bloom. They noted the plants likely exhibited this behavior to protect the pollen from rain.

Don’t you love how the corona color on these Narcissus 'Golden Echo' fades into the petals? They echo the gold found in the cup. Oh, breeder, I see what you did with the name there…

Seeing the beautiful Camassia leichtlinii 'Alba' reminds me that I need to try Camassia in Texas. I do love this white selection of camas or quamash.

I’m a sucker for the clusiana tulips. They look like cute lollypops you could just eat up. Here’s the peachy-colored Tulipa clusiana var. chrysantha.

And, here’s the lovely Tulipa clusiana 'Cynthia'.

And, the faded peppermint colors of Tulipa clusiana 'Lady Jane'. I’ve GOT to order some clusiana tulips for planting this fall!

I’m always enchanted by the yellow bells of the native Uvularia grandiflora.

I saved one of my favorites for last. Watching Scilla peruviana flowers unfurl was always a true spectacle to enjoy in the garden. It was like watching a firework explode over days.

And, of course, April at the JC Raulston Arboretum brings to mind their galas from years past. Will Hooker and his permaculture class built this incredible dragon one year out of bamboo to tie into the Asian theme.

True Grit: Planting a Gravel Garden with Students

“How did I get here?” I asked myself in anxious jubilation last Friday as I watched the dump truck release its load of 6 cubic yards of gravel behind the agriculture building. The driver, a super nice guy named Mike, wished us luck on planting our gravel garden as he drove off. He had never heard of growing plants in gravel. And, up until a few years ago, really neither had I.

But, the rhetorical question really made me reflect. Why was I having students plant common perennials in gravel?

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Every two years I teach Herbaceous Plants, a class devoted to the annuals and perennials that will do well in east Texas and the southeast. This semester is the fourth time that I have taught the class, and each year I get a little more focused on the use of these plants in naturalistic design. In the past years, I’ve had students design and plant prototype designed plant communities in our edible garden. We deemed these food prairies since the garden was centered on food for people, and these plantings would provide food for insects. They would also provide food for the mind where the students and I could learn better how to do this sustainable type of planting.

Through the installation of naturalistic plantings, I’ve realized that the weed management is a constant struggle. While weeds are already a challenge during the active growing season, they are also problematic during the cooler months here in the southeast when the weather is mild enough to allow persnickety winter weeds to continue growing. The hope with naturalistic plantings is that they can close quickly enough to choke out potential weeds, and if the weed bank is depleted prior, it certainly helps. But, management often requires the use of mulch, pre-emergent herbicides, and/or wedding to control such issues. Other friends and colleagues have commented on their frustration that weed management after installation can be quite cumbersome especially with the dense planting used.

A Permanent Mulch

In my studies of naturalistic design, I’ve learned that weed management can be induced by increasing the stress of the site conditions and by lowering the level of nitrogen in the soil. An inorganic mulch layer of gravel, sand, recycled concrete, or other crushed aggregates achieves both of these goals. I first became aware of the science behind this approach when I heard Cassian Schmidt speak at the 2016 Perennial Plant Conference. He had detailed data down to minutes per square meter on how much management must occur for different types of plantings, and rocky soils that create more stressful conditions for the plants reduce management time. I realized I had seen these types of plantings before. I had visited Beth Chatto’s gravel garden in England where famously none of the plants have been irrigated. And, of course the gravel garden at Chanticleer has always captured my attention.

The gravel garden at Beth Chatto’s nursery in the UK was once a parking lot. It now features denizens from around the world that survive in more stressful conditions.

The gravel garden at Chanticleer hosts a wide range of species that tolerate growing in harsher conditions.

Hearing Cassian Schmidt’s presentation really piqued my interest in using gravel as a planting medium, but I had my doubts. I really hadn’t embraced that stress was an asset yet as I had studied about emulating nature in the other direction and enriching soils with organic matter to prevent problems with edibles. I started to think about the plant communities I had seen in west Texas or the North Carolina barrens. Perhaps it was possible, and we could make garden soil more stressful for plants.

I started looking for more information on the subject. I learned about Peter Korn and how he grows plants in straight sand conditions, and again, I was amazed that plants could survive in such a scenario. In 2019, I attended the Perennial Plant Association’s (PPA) meeting in Chicago, and on a tour visited Olbrich Botanical Gardens where Jeff Epping is director of horticulture. Right off the bus was an incredible perennial planting at the entrance. I would discover from the conversations of the people around me that the thriving plants I saw were planted in 4 to 5 inches of gravel! Once inside, we would discover other gravel plantings where Jeff had overseen their install. I’ll add here that I’ve learned much from looking at a presentation he gave at PPA in 2017.

Perennials thrive in a gravel garden at the entrance to Olbrich Botanical Gardens.

Here’s another gravel garden further in Olbrich Botanic Gardens that features Calamintha, Sporobolus, Allium, and other species.

Around the same time, I was delighted to see Ben O’Brien have success with planting in combinations of sand, gravel, and recycled concrete in Canada. He did some incredible trials of different species in these mixed aggregates, and the complete results of his work including a species-by-species breakdown of his trial can be found on his website.

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HOW WELL DO GRAVEL GARDENS WORK IN THE SOUTH?

But, most of these plantings are found up north—Wisconsin, Pennsylvania, Ontario, England, Germany, and Sweden. The question is will they work in the deep south where we get quite hot later in the summer and can have prolonged dry periods. And, again I’m not focusing on xeric or alpine plants but instead common perennials to grow in gravel.

So, I decided with my class this year that we would install a gravel garden to attempt to answer this question. This class would be slightly different because due to COVID-19 we condensed the class from16 weeks down to a half semester of 8 weeks. We would just double the time we met each week to cover the same material. But, that also meant we had to expedite the process of developing the garden.

I should also note for those of you concerned about my students or me in a COVID-19 environment that I have been extremely cautious. (I’m that cautious person who hasn’t eaten out in a restaurant since March 2020, hasn’t travelled to see family or really anywhere, and was told back last spring when I was rearranging my classes that I “drank the Kool-Aid” about the hyped-up concerns over COVID-19.) There were only seven students in the class, which allowed for social distancing through this entire course, and students wore masks as well, too.

Here is the site of our future gravel garden at the bottom of Sprout, our edible garden in the Plantery. The Plantery is our teaching gardens, grow houses, and micro-farm Sprout located near the SFA Agriculture building where we can provide students with hands-on learning opportunities.

Prior to installing the garden, I covered many of the basics of naturalistic design from competitor—stress-tolerator—ruderal survival strategies to Nigel Dunnett’s FLOW design method in class. Students easily understood Nigel’s classifications of anchors (primary plants in the installation), satellites (plants that provide seasonality around the anchors), matrix species (the groundcover species, typically grasses), and free floaters (self sowers that pop up here and there). We then practiced iterating and creating naturalistic plantings, first as students in small groups and then as solo projects.

For our gravel garden, I provided students with a plant list of species that we had both ordered and propagated. Normally, we would choose the plants early in class and then order them or grow them, but the shortened semester forced my hand. I also provided students with a rendering of the site dimensions where the students were able to apply what they learned in class, and from a measuring lab we determined that the full sun site was approximately 400 square feet in size. Below are two anonymous examples of the drawings that students developed for the class.

From these drawings I then synthesized them into one cohesive design. Again, normally, we would do this activity in class, but with the time limitations I decided to render the design myself. The design we went with was to have taller edge species at the back of the planting near the fence that my nursery management lab had built the previous fall. Then, a sinuous curve would snake through the bed with plant anchors and plant satellites arranged on either side of the bed. Some large rocks remained in the bed from a previous planting that students like to sit on and take pictures, and we decided to just use them as part of the design. The taller species would provide a nice floral backdrop and the pathway would pass right by these larger stones.

The biggest challenge was sourcing the mineral mulch. I had almost given up when I found a company in town that sold baked clay that is used on roads, and it appeared to be clean of weeds, had the angular size of grit that we desired, and had that gray-blue color that I had seen before at other gardens. It was a bit pricey coming in a $110 a cubic yard, but I was prepared to pay for good quality material. This gravel was delivered last Friday in anticipation of planting this week.

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TUESDAY MORNING CLASS, SPREADING THE GRAVEL

We finished leveling the soil in our morning class. We then put stakes in that had two markings, one for the soil line and one for the gravel line. Students then began to spread at least 4 inches of gravel over the entire site. We then went back and checked with trowels to make sure that the gravel depth was right over the bed.

A view of the site from the ground prior to any gravel. Oh, and in case you’re curious about the white in the Sprout garden, those are floating row covers over tomatoes. We had a freeze forecasted this week!

Students begin spreading gravel over the site.

The stakes really helped us check the gravel depth.

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TUESDAY AFTERNOON LAB, PLANTING THE ANCHORS AND SATELLITES

In the afternoon lab, we flagged our pathway and then began placing the the anchors and satellite species into the bed. I paired students off to look at the design and then place plants appropriately with notes on how many plants should be placed in each area. From reading about gravel gardens I was aware that we needed to knock off excess soil to decrease the organic matter in the bed and remove the top of the substrate from the rootballs to reduce the weed load we might be putting in the beds. So, when we began planting, I instructed students to use Tubtrugs to accomplish these tasks and not get soil in the gravel. Afterwards, we watered the plants in well.

Students begin setting out plants based on the design.

Mike and Hanna check the design for the placement of Symphyotrichum oblongifolium ‘Raydon’s Favorite’.

The anchors and satellites laid out prior to planting.

Brendan plants a Pycnanthemum tenuifolium into gravel.

Nyree knocks the soil off a Pycnanthemum tenuifolium plant.

Hope waters the plants in after planting.

The anchors and satellites planted into gravel.

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THURSDAY MORNING CLASS, PLANTING THE MATRIX

We wrapped up the planting Thursday morning by planting the matrix species. We planted more Nassella, and then we introduced a few Sporobolus heterolepis in the front and Muhlenbergia reverchonii in the back. We also scattered Echinacea purpurea and Echinacea purpurea ‘White Swan’ through the latter last two grasses to see how they will do on site as self sowers.

Planting round two begins with installing the matrix layer.

The gravel garden fully planted!!! Yay!!! We still haven’t decided what edging to use to mark the path. We may wait until the plants fill in a bit to determine that. We are thinking willow, bent metal, or maybe just leaving it bare.

An overview perspective of our new gravel garden. And, in case you are wondering about the area to the right of the gravel garden that’s been recently cleared, we eventually want to turn that into a practice patio garden where students can overhaul it every few years. Since we are a small program with limited funds, we tend to piecemeal projects together. This gravel garden pathway will feed right into the space as if it is part of an extended back yard to the mock patio.

As Jeff Epping suggested in his presentation, we will irrigate often for the next several weeks until plants are established. And, reflecting back over the whole process the one change I want to make is to try to find cheaper gravel that achieves the same effect as this baked clay product.

I look forward to seeing the true grit that these plantings will offer for us here in the southeast. I asked students what they loved most about this project. Common comments were how good it looked at the end, learning that plants could grow in gravel, and the excitement to see how the planting will look in a few months. I, too, have that same excitement, though with a dash of the fear of failure. But, I know that failure feeling is essential when trying something new that pushes the boundaries of what is possible and learning new things about horticulture. And, as I kidded with the students, should this fail, well, we have 6 cubic yards of gravel for our future walkways! :-)