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?


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 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.

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.

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.

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.


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 student…

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.

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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 design for the gravel garden.  The number following the species indicates the number of plants to set out at that location.  For guidelines we used the posts from the fence.

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.


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!

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.

Students begin spreading gravel over the site.

The stakes really helped us check the gravel depth.

The stakes really helped us check the gravel depth.


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.

Students begin setting out plants based on the design.

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

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

The anchors and satellites laid out prior to planting.

The anchors and satellites laid out prior to planting.

Brendan plants a Pycnanthemum tenuifolium into gravel.

Brendan plants a Pycnanthemum tenuifolium into gravel.

Nyree knocks the soil off a Pycnanthemum tenuifolium plant.

Nyree knocks the soil off a Pycnanthemum tenuifolium plant.

Hope waters the plants in after planting.

Hope waters the plants in after planting.

The anchors and satellites planted into gravel.

The anchors and satellites planted into gravel.


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.

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.

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…

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! :-)

 

Dipping into Baptisia

If I were forced to choose a favorite herbaceous perennial genus of all time, it would be Baptisia. I'm a fan of all the species, and I do hope one day to have them all growing here at my house. I even love the hybrids, some of which occur naturally where ranges overlap.

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But, why Baptisia? I think of the many perennials we have in our gardens, it is one of the few that truly offers four season interest. They erupt out of the ground in early spring with their asparagus-like shoots that soon fill with trifoliate, clean foliage. Then, like a colorful, slow moving comet with long tails the inflorescences rise with dozens or even hundreds of flowers present on them. And, I do adore the classic papilionaceous flowers of Baptisia, their banner, wings, and keel that greet pollinators. Bees push against the keel to help get access to the nectar, and that force lowers this fused petal to expose the stamens and pistils. (You can mimic this act by pulling down on the keel to see the stamens.) In a beautiful example of co-evolution, lower flowers that are mostly female are preferred because they have higher nectar rewards. Bees will then move towards the higher flowers on the same inflorescence, which tend to be more male and have copious pollen. When they move to the next flower, they then carry fresh pollen to increase the chances of crossing with the nectar-rich, female flowers of another plant. Once flowers are pollinated they swell into bloated green pods that contain seed. These eventually turn black, and the seeds dehisce, which creates a rattle that even Native American children used for entertainment. These pods will often remain through the winter, held high on the inflorescences that were full of blooms over half a year ago.

But, there's more to this wonderful native. One of the things I love most about the taller Baptisia australis and Baptisia alba is their height early in the season that allows me to create layers in plantings. Tall herbaceous plants are rare in early spring, but their quick emergence puts them in a unique category. Deer tend to avoid them (note the word *tend to* there). Baptisia overall are very drought tolerant, partly because their tap roots grow deep. Wild indigos are also all nitrogen fixers and thus help to enrich the soil in which they grow. I’ve already discussed the interplay between Baptisia and bees, but I can’t forget that some butterflies even host on them. And, for cut flower enthusiasts, they perform well in a vase. I regularly have cuttings last a week for me.

There's also much story and history with this plant. They are called wild indigos because members of this genus was used as a dye by Native Americans and then colonists. In fact, Baptisia comes from the Greek bapto meaning “to dip” or “to dye.” Allan Armitage in Herbaceous Perennial Plants stated that back in the 1700's, indigo was derived from Indigofera, but diminished supply caused the English government to ask farmers in the southeast US to grow wild indigo. Thus, Baptisia became one of the first crops to be subsidized by a government. Evidently the process was challenging, and that's why this species is grown more for its ornamental and ecological purposes rather than coloring textiles.

 
Look closely at the flowers and you can see the upper banner, the wings, and the mostly hidden keel on the flowers of Baptisia alba.

Look closely at the flowers and you can see the upper banner, the wings, and the mostly hidden keel on the flowers of Baptisia alba.

 

Growing up, I didn't have Baptisia around me in Tennessee. I would see it in nurseries, and really Baptisia australis was all I knew. But, several years ago right after moving to Texas, I was delighted to discover Baptisia do grow wild here. While the less showy stem mound Baptisia nuttalliana is the most prevalent, I have been able to find Baptisia alba, Baptisia bracteata, and Baptisia sphaerocarpa in the wild. And, I hope to soon see Baptisia australis in north Texas.

Of the three I’ve encountered, I have most welcomed Baptisia alba into my garden (Don't worry, I'm bulking up the other two!). Years ago, I discovered a massive population of this species about fifteen minutes from our house. Of course, I say massive because I had never seen it in its native habitat. I've seen one or two plants in a garden over the years, but at this site there were at least a several hundred individuals growing from the top of a hillside all the way down toward the floodplain edge. I remember thinking, "What wonderful place is this that Baptisia grows wild and free?" Seeing this stand occurring naturally made me realize that Baptisia could be used en masse for spectacular effect. I will add a nomenclature note. Some authorities call this form Baptisia alba var. macrophylla, but I have yet to read anything about Baptisia alba var. alba. It is possible this name is just a synonym of Baptisia alba.

Here’s one of the first photos that I took of this incredible population of Baptisia alba.

Here’s one of the first photos that I took of this incredible population of Baptisia alba.

This photo was taken a week earlier when Thomas Rainer visited our students and shows how much these plants can rise and elongate within a week.

This photo was taken a week earlier when Thomas Rainer visited our students and shows how much these plants can rise and elongate within a week.

In some spots Baptisia alba was highly sociable with some plants so thick they touched each other and formed a hedge.

In some spots Baptisia alba was highly sociable with some plants so thick they touched each other and formed a hedge.

Here you can see just how close some Baptisia alba stems grew together.

Here you can see just how close some Baptisia alba stems grew together.

The neutral white flowers of Baptisia alba allow it to combine well with other colors like the light blue Salvia lyrata and coral Castilleja indivisia.

The neutral white flowers of Baptisia alba allow it to combine well with other colors like the light blue Salvia lyrata and coral Castilleja indivisia.

 
Karen provides scale for some of these large forms of Baptisia alba.  It was even over my head!

Karen provides scale for some of these large forms of Baptisia alba. It was even over my head!

 
Like comets with long tails, the racemes rise into the sky and glow a beautiful white.

Like comets with long tails, the racemes rise into the sky and glow a beautiful white.

The swelling seedpods of Baptisia alba.  Eventually, these will harden and turn into rattles.

The swelling seedpods of Baptisia alba. Eventually, these will harden and turn into rattles.

At this site there were a few individuals that exhibited more yellow flowers, shorter habit, and more compact inflorescences.  These were likely hybrids with Baptisia nuttalliana.

At this site there were a few individuals that exhibited more yellow flowers, shorter habit, and more compact inflorescences. These were likely hybrids with Baptisia nuttalliana.

A close up of the likely Baptisia alba × nuttalliana hybrid.

A close up of the likely Baptisia alba × nuttalliana hybrid.


From this population, I took cuttings and also collected seed later in the fall, scarified it, and sowed it. And, now I have plants galore at my house. They are come into full bloom in April. I love watching their evolution as the shoots rise with a tinge of smoky purple, likely due to some anthocyanin sunscreen to contend with the early spring sunshine. I use them as plant anchors in my beds, their height providing focal points above the other flowers. And, while I've heard it recommended to plant one here and there to mimic "how they occur in nature", from this population I’ve learned not to be afraid to put then closer together.

 
Either by itself or in a group, Baptisia alba is most welcomed in a garden.

Either by itself or in a group, Baptisia alba is most welcomed in a garden.

 
A few weeks ago, we had this enchanting fog rise over the garden after an afternoon rain that created some opportunities for photographing Baptisia alba against a glorious sunset.

A few weeks ago, we had this enchanting fog rise over the garden after an afternoon rain that created some opportunities for photographing Baptisia alba against a glorious sunset.

The fog thickened, and created this wonderful atmosphere to enjoy the silhouettes of Baptisia alba.

The fog thickened, and created this wonderful atmosphere to enjoy the silhouettes of Baptisia alba.

I’ll be honest. I feel like I’ve just dipped into this incredible genus, and I still haven’t learned all its secrets. One day I hope to have a backyard full of Baptisia, not just Baptisia alba, but many species of many colors. In growing them, I can’t wait to learn more about this wonderful group of plants.

Easter Weekend at Biltmore

Last year for Easter, I shared about a wonderful trip that I took to the North Carolina mountains back in 2011 over this holiday.  The highlight I shared was visiting the virgin forest Joyce Kilmer Memorial Forest on Easter morning.  But, the weekend had other forays, too.

That year, Easter fell on April 24, the second latest date that Easter can be (April 25 is the latest). Colleagues had told me that the fourth weekend in April was one best times to visit Biltmore because the last of the tulips overlapped with the first of the azaleas.

If you aren’t familiar with the Biltmore estate in Asheville, North Carolina, it is an incredible place to behold. It was once home to George Vanderbilt, and the house is the largest private home in America with over 170,000 square feet! Frederick Law Olmsted designed the grounds and gardens for Vanderbilt as one of his last large projects, and Olmsted even encouraged him to grow trees. From that prompt Vanderbilt started one of the first forestry programs in the United States. While the house holds the history of the family, the gardens holds a plethora of plant delights.

In planning the weekend, I decided that visiting Biltmore early Saturday morning would fit best into the schedule because the crowds would be small.  Then, I could do wilderness jaunts the rest of the weekend. I hope you enjoy this eye candy as I relive a weekend at the Biltmore estate through this photolog.

I chuckle reflecting back on my handful of visits to Biltmore because I haven’t made it through the house yet.  For me, the gardens are what continually capture my attention.  

I chuckle reflecting back on my handful of visits to Biltmore because I haven’t made it through the house yet.  For me, the gardens are what continually capture my attention.  

One of my favorite views at Biltmore is near the house looking out to the distant mountains across a vast forest.  This visit the vista was a bit obscured by clouds, but the gray skies helped reduce the harsh shadows for better photography.

One of my favorite views at Biltmore is near the house looking out to the distant mountains across a vast forest. This visit the vista was a bit obscured by clouds, but the gray skies helped reduce the harsh shadows for better photography.

Up closer to the house, I admired the large Wisteria on the arbor.  Yes, I know the Asian species are quite invasive, and I always recommend planting Wisteria fructescens or Wisteria macrostachya.  But, still, it was spectacular seeing thi…

Up closer to the house, I admired the large Wisteria on the arbor.  Yes, I know the Asian species are quite invasive, and I always recommend planting Wisteria fructescens or Wisteria macrostachya.  But, still, it was spectacular seeing this behemoth of a planting.  

As I made my way toward the walled garden and tulip display, I passed by a beautiful mass of Hyacinthoides hispanica under this Fagus in the shrub garden.

As I made my way toward the walled garden and tulip display, I passed by a beautiful mass of Hyacinthoides hispanica under this Fagus in the shrub garden.

I reached the walled garden and was mesmerized by the tulip displays.  Warm pastels were surrounded by dark purples, and in the center a ring of white and black tulips provided contrast. With all the oval flowers it was like an Easter egg hunt …

I reached the walled garden and was mesmerized by the tulip displays.  Warm pastels were surrounded by dark purples, and in the center a ring of white and black tulips provided contrast. With all the oval flowers it was like an Easter egg hunt on steroids!

 
The arbor in the above image had these windows that created vistas for looking out into the garden.

The arbor in the above image had these windows that created vistas for looking out into the garden.

 
A shot from the west side of the arbor.  In the distance you can see the wall that gives the walled garden its name.  The perennial borders that surround the color beds were also coming to life.  Each time I visit here I always enjoy seeing the…

A shot from the west side of the arbor. In the distance you can see the wall that gives the walled garden its name. The perennial borders that surround the color beds were also coming to life.  Each time I visit here I always enjoy seeing the combinations the gardeners have made. 

In the perennial borders, I quite liked this contrasting color combination of yellow with purple, tending toward the side of blue, flowers

In the perennial borders, I quite liked this contrasting color combination of yellow with purple, tending toward the side of blue, flowers

A clump of Hyacinthoides hispanica emerges from a layer of Stachys byzantina.

A clump of Hyacinthoides hispanica emerges from a layer of Stachys byzantina.

White was a popular color used on the edges of the walled garden.  Here a single flower of Lamprocapnos (Dicentra) spectabilis ‘Alba’ rests on foliage.

White was a popular color used on the edges of the walled garden. Here a single flower of Lamprocapnos (Dicentra) spectabilis ‘Alba’ rests on foliage.

It was such good design to elicit harmony and repetition by pairing these similar-looking yet opposing inflorescence growth habits of this Wisteria and Baptisia.

It was such good design to elicit harmony and repetition by pairing these similar-looking yet opposing inflorescence growth habits of this Wisteria and Baptisia.

Paeonia lactiflora 'Krinkled White' living up to its namesake with the white handkerchief petals.

Paeonia lactiflora 'Krinkled White' living up to its namesake with the white handkerchief petals.

On my way out of the walled garden, I passed this incredible Halesia.    I so admire silverbells for their brilliant white flowers that sway in the breeze.

On my way out of the walled garden, I passed this incredible Halesia. I so admire silverbells for their brilliant white flowers that sway in the breeze.

Leaving the walled garden and conservatory area, I entered the azalea garden.  It was erupting with color during my visit.

Leaving the walled garden and conservatory area, I entered the azalea garden. It was erupting with color during my visit.

While I like the evergreen azaleas, I really love the native ones.  There’s just something about their flowers that makes me weak in the knees.  These plants are magnets for early season butterflies like swallowtails.  My jaw dropped seeing the…

While I like the evergreen azaleas, I really love the native ones.  There’s just something about their flowers that makes me weak in the knees. These plants are magnets for early season butterflies like swallowtails. My jaw dropped seeing these massive Rhododendron austrinum plants.

A closeup of the flowers of Rhododendron austrinum

A closeup of the flowers of Rhododendron austrinum

Rhododendron canescens was a favorite of mine from back in west Tennessee, and I was impressed seeing such large shrubs here at Biltmore.  They smell great, too!

Rhododendron canescens was a favorite of mine from back in west Tennessee, and I was impressed seeing such large shrubs here at Biltmore. They smell great, too!

Rhododendron canescens is often confused with Rhododendron periclymenoides, but Rhododendron canescens has gland-tipped hairs on the corolla tube; Rhododendron periclymenoides does not.

Rhododendron canescens is often confused with Rhododendron periclymenoides, but Rhododendron canescens has gland-tipped hairs on the corolla tube; Rhododendron periclymenoides does not.

This visit was my first encounter with Rhododendron alabamense.  This species can be identified by its white petals, yellow blotch, and lemon fragrance.

This visit was my first encounter with Rhododendron alabamense. This species can be identified by its white petals, yellow blotch, and lemon fragrance.

Another species I was delighted to find was Rhododendron vaseyi, a rare and at risk native azalea that occurs in 11 counties in North Carolina.  I had seen it on the Blue Ridge Parkway, and here I happened upon it in the garden.

Another species I was delighted to find was Rhododendron vaseyi, a rare and at risk native azalea that occurs in 11 counties in North Carolina. I had seen it on the Blue Ridge Parkway, and here I happened upon it in the garden.

 
There were other azaleas I didn’t know, likely hybrids or good wild selections.  I LOVE this color form.  Please send me a message if you know the cultivar!

There were other azaleas I didn’t know, likely hybrids or good wild selections. I LOVE this color form. Please send me a message if you know the cultivar!

 
Further back from the azaleas I found a wilder area of the garden where Asarum canadense was able to form large colonies.

Further back from the azaleas I found a wilder area of the garden where Asarum canadense was able to form large colonies.

Osmundastrum cinnamomeum fiddleheads unfurl amongst a matrix of green, Packera, and Hyacinthoides.

Osmundastrum cinnamomeum fiddleheads unfurl amongst a matrix of green, Packera, and Hyacinthoides.

A closeup of the pubescent fiddleheads of Osmundastrum cinnamomeum.

A closeup of the pubescent fiddleheads of Osmundastrum cinnamomeum.

 
One last look at the beauty of the Biltmore gardens.  Yes, mid-April is an incredible time to visit for inspiration and to witness the marvels of spring.

One last look at the beauty of the Biltmore gardens. Yes, mid-April is an incredible time to visit for inspiration and to witness the marvels of spring.

 

March at the JC Raulston Arboretum

This post is 3 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.

March was always a moody month in Raleigh. Well, I guess isn’t it everywhere? Some years it was filled with gorgeous days, and others it taunted the gardener with late freezes. Nevertheless, there always seemed to be plants in bloom some time during the month at the JC Raulston Arboretum. This month, I look back at some of my favorite trees, shrubs, and perennials that welcomed spring. I hope these images inspire you to try some new plants in your garden. I know learning about them helped to build my palette of plants to use for the beginning of the gardening season.

THE TREES

There was an incredible Magnolia collection at the arboretum.  Here the vigorously growing Magnolia × loebneri 'Merrill' flowers in the White Garden.  This selection is quite hardy up into the northern states.

There was an incredible Magnolia collection at the arboretum. Here the vigorously growing Magnolia × loebneri 'Merrill' flowers in the White Garden. This selection is quite hardy up into the northern states.

One of my favorite magnolias is Magnolia × kewensis 'Wada's Memory'.  I love its cut-handkerchief-like petals, and I’m considering using this cultivar around our house.

One of my favorite magnolias is Magnolia × kewensis 'Wada's Memory'. I love its cut-handkerchief-like petals, and I’m considering using this cultivar around our house.

Each spring I loved seeing the floriferous Magnolia stellata 'Chrysanthemumiflora' in bloom.  The pink blossoms are so voluminous, and this tree’s short stature welcomes its use in smaller gardens.

Each spring I loved seeing the floriferous Magnolia stellata 'Chrysanthemumiflora' in bloom. The pink blossoms are so voluminous, and this tree’s short stature welcomes its use in smaller gardens.

Near the Ruby McSwain center was the Asian Sassafras tzumu with its tiered branching habit classic to Sassafras species.

Near the Ruby McSwain center was the Asian Sassafras tzumu with its tiered branching habit classic to Sassafras species.

As the flowers fade, the new foliage emerges on Sassafras tzumu with a similar textured Yucca in the background.

As the flowers fade, the new foliage emerges on Sassafras tzumu with a similar textured Yucca in the background.

J.C. raved about Halesia diptera var. magniflora and for good reason.  This variety from Florida highlands features beautiful white flowers a little bigger than a thimble that cover the tree in early spring.  This species does well in Texas, too.

J.C. raved about Halesia diptera var. magniflora and for good reason. This variety from Florida highlands features beautiful white flowers a little bigger than a thimble that cover the tree in early spring. This species does well in Texas, too.

 
A close up of Halesia diptera var. magniflora

A close up of Halesia diptera var. magniflora

 
I can’t wait to try Melliodendron xylocarpum in Texas.  I adored this tree’s Easter egg shaped buds that would open to…

I can’t wait to try Melliodendron xylocarpum in Texas. I adored this tree’s Easter egg shaped buds that would open to…

…beautiful star-shaped white flowers.  I recall that some years Melliodendron xylocarpum would get burned by late freezes, but like many early spring flowering plants, planting them is certainly worth the risk.

…beautiful star-shaped white flowers. I recall that some years Melliodendron xylocarpum would get burned by late freezes, but like many early spring flowering plants, planting them is certainly worth the risk.

THE SHRUBS

Exochorda racemosa is shrub that takes our heat and humidity in the south well.  The little buds look like pearls, hence the name pearlbush.  I always enjoyed looking at the intricacies of the flowers once they open.

Exochorda racemosa is shrub that takes our heat and humidity in the south well. The little buds look like pearls, hence the name pearlbush. I always enjoyed looking at the intricacies of the flowers once they open.

Spiraea thunbergii 'Ogon' is a reliable flowering shrub that is covered with white flowers in early spring and followed by thin, golden leaves.

Spiraea thunbergii 'Ogon' is a reliable flowering shrub that is covered with white flowers in early spring and followed by thin, golden leaves.

 
A subtle color echo between the emerging foliage on Spiraea thunbergii 'Ogon' and its orange pistils.

A subtle color echo between the emerging foliage on Spiraea thunbergii 'Ogon' and its orange pistils.

 
Last month I shared my love of Stachyurus.  Even more plants would be flowering in March.  Here Stachyurus praecox 'Issai' flowers with a Chaenomeles in the background.

Last month I shared my love of Stachyurus. Even more plants would be flowering in March. Here Stachyurus praecox 'Issai' flowers with a Chaenomeles in the background.

There was even a Stachyurus selection—Stachyurus praecox 'Rubriflora'—that had buds and petals blushed pink.

There was even a Stachyurus selection—Stachyurus praecox 'Rubriflora'—that had buds and petals blushed pink.

A really interesting and uncommon shrub I learned about at the arboretum was Parrotiopsis jacquemontiana.  This member of the witch hazel family would be covered in flowers in March.

A really interesting and uncommon shrub I learned about at the arboretum was Parrotiopsis jacquemontiana. This member of the witch hazel family would be covered in flowers in March.

 
In this close up of the flowers on Parrotiopsis jacquemontiana, you can see the plethora of stamens and the skirt of white bracts underneath.

In this close up of the flowers on Parrotiopsis jacquemontiana, you can see the plethora of stamens and the skirt of white bracts underneath.

 
 
Edgeworthia chrysantha was in full bloom in March many years at the arboretum.  The flowers face down, likely to protect the pollen from rain.

Edgeworthia chrysantha was in full bloom in March many years at the arboretum. The flowers face down, likely to protect the pollen from rain.

 
Neviusia alabamensis is a novelty native shrub that slowly spreads via rhizomes in the garden.  It is rare throughout its range, but deserves wider use for its dainty flowers.

Neviusia alabamensis is a novelty native shrub that slowly spreads via rhizomes in the garden. It is rare throughout its range, but deserves wider use for its dainty flowers.

I enjoyed the pompom flowers of Neviusia alabamensis so much that I now have this growing in my Texas garden.

I enjoyed the pompom flowers of Neviusia alabamensis so much that I now have this growing in my Texas garden.

The late witch hazels would still be flowering in March.  Here Hamamelis mollis 'Wisley Supreme' flowers with a carpet of Narcissus underneath.

The late witch hazels would still be flowering in March. Here Hamamelis mollis 'Wisley Supreme' flowers with a carpet of Narcissus underneath.

While most lilacs don’t do well in the south, Syringa × laciniata was always a beautiful bloomer in the arboretum and tolerated heat well.

While most lilacs don’t do well in the south, Syringa × laciniata was always a beautiful bloomer in the arboretum and tolerated heat well.

 
The lavender flowers of Syringa × laciniata

The lavender flowers of Syringa × laciniata

 

THE PERENNIALS

I also learned about Tulipa clusiana selections at the arboretum.  This species tends to do better in the south and can grow well in gravel gardens.  Here ‘Cynthia’ flowers with creamy yellow and salmon petals.

I also learned about Tulipa clusiana selections at the arboretum. This species tends to do better in the south and can grow well in gravel gardens. Here ‘Cynthia’ flowers with creamy yellow and salmon petals.

Another clusiana type was ‘Peppermint Stick’, named for its red and white petals.

Another clusiana type was ‘Peppermint Stick’, named for its red and white petals.

Celebrating Emergence

The shift to spring is now palpable here at our east Texas homestead. I notice the sun's early morning rays shining more in our backyard, the temperature is hovering the in 60's or 70's most days, and spots of green are popping up in the landscape.

Emergence in the plant world is filled with such anticipation. Around us life is erupting, and it is so good to see fresh growth in a landscape scarred and burned from the extreme cold a fortnight ago.

The daffodils are up. Well, most of them are. I thought this would be a daffodil-less spring as many of the early tazetta types from the Mediterranean were bleached white. But, those that have more northern European blood seem to have made it through safely. The yellow-orange 'Ceylon' and large-cupped yellow 'Carlton' are now beginning to bloom. I noticed their buds above the snowline, but they still survived the cold. These are two Narcissus cultivars that actually do well for us here in east Texas and will increase in number with the years. Most modern hybrids just don't get adequate chilling to flower or grow well.

A bit of burn on the tips of the foliage of these ‘Ceylon’, but other than that, the cold didn’t phase them.

A bit of burn on the tips of the foliage of these ‘Ceylon’, but other than that, the cold didn’t phase them.

Narcissus pseudonarcissus are now flowering, too. They are much smaller than the varieties above, but I love their diminutive size. I recall seeing their minute buds huddled among the blue-green foliage as I scurried about preparing for the coming cold and wondering if they would survive. Seeing their buttery yellow coronas reminds me of my youth and the abandoned yards full of them on the backroads in Tennessee marking where homes once stood. Even then I would pick handfuls of them to bring their sweet scent into our house, much like I did ahead of the two inches of rain we got this past weekend.

This line of Narcissus pseudonarcissus flowers faces south, soaking in the sun.

This line of Narcissus pseudonarcissus flowers faces south, soaking in the sun.

Ahead of the rain I divided some large clumps of Narcissus pseudonarcissus and planted them into the beds near our house that I have been developing into naturalistic plantings since our arrival here a little over three years ago. These plantings needed more early spring color, and I plugged in the bulbs before the rain started amongst the emerging foliage of Pycnanthemum and a nice purple foliage form of Tradescantia gigantea I found.

I randomly scattered Narcissus pseudonarcissus into this bed over the weekend.  Though I’m not done yet, my goal is to have small groupings, denser in the middle and then less bulbs on the outside.

I randomly scattered Narcissus pseudonarcissus into this bed over the weekend. Though I’m not done yet, my goal is to have small groupings, denser in the middle and then less bulbs on the outside.

Ahead of the rain was also a good time to move 20+ Penstemon tenuis and 30+ Penstemon digitalis plants I grew in propagation beds from last year. Both were derived from seed that I collected from plants growing here, and they were just barely beginning to produce shoots out of their basal rosettes. Now I feel like I have enough plants to make an impact come April for the purple-flowering Penstemon tenuis and May for the white-flowering Penstemon digitalis. I was surprised at how shallow their root systems were. I was able to scoop them up with a shovel almost like one would scoop lasagna out of a dish and place into a similar shaped hole.

A wheelbarrow of Penstemon digitalis ready for planting.  You can see the fresh foliage beginning to pop.

A wheelbarrow of Penstemon digitalis ready for planting. You can see the fresh foliage beginning to pop.

Nearby other natives are emerging, and it is a real cast of characters—Arnoglossum plantagineum, Trillium ludovicianum, Antennaria parlinii, Sanguinaria canadensis, Stenanthium gramineum, and even my Sarracenia in the bog. All of them know it’s time to grow.

I delight in seeing the hosta-like foliage of Arnoglossum plantagineum.  Plants have finally gotten to a decent size at our place, and soon their shoots will rise for form a white corymb of rice-shaped flowers.

I delight in seeing the hosta-like foliage of Arnoglossum plantagineum. Plants have finally gotten to a decent size at our place, and soon their shoots will rise for form a white corymb of rice-shaped flowers.

I was also happy to see my Trillium ludovicianum emerging amongst the groundcover of Antennaria parlinii I planted to mark the ephemeral.  You can barely see the chicken wire cage that I planted it in to protect it from the gophers that plague our p…

I was also happy to see my Trillium ludovicianum emerging amongst the groundcover of Antennaria parlinii I planted to mark the ephemeral. You can barely see the chicken wire cage that I planted it in to protect it from the gophers that plague our property, and if you look closely, you’ll see some one-leaved baby Trillium in the center!

The fists of Sanguinaria canadensis are shoving their way out of the soil and begun to unfurl as leaves.

The fists of Sanguinaria canadensis are shoving their way out of the soil and begun to unfurl as leaves.

The slivers of foliage on Stenanthium gramineum emerge from the ground.  I’ve always found their maroon sheaths near the ground to be attractive but quickly hidden by the foliage.

The slivers of foliage on Stenanthium gramineum emerge from the ground. I’ve always found their maroon sheaths near the ground to be attractive but quickly hidden by the foliage.

I squealed this weekend when I discovered the antennae-like flower buds emerging on this Sarracenia flava ‘Black Ascot’ when cutting back the pitchers.

I squealed this weekend when I discovered the antennae-like flower buds emerging on this Sarracenia flava ‘Black Ascot’ when cutting back the pitchers.

Yes, all this fresh growth of spring is truly wonderful . Sure, we may have another frost or two along the way, but for now I will celebrate emergence and the return of my many photosynthetic friends to the garden after their long slumber. It is so good to see them again.