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.

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.

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.

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.

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.


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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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?

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.

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.

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.

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.

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.

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.

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.

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

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.

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

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'?

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'.

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.

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'.

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?

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.

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.

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…

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.

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.

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, 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!

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’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.

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.

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?


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.

2021-0415-205 Baptisia alba-save4web.jpg

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.