Looking lovely in the garden this week is the amazing native small tree, Aesculus parviflora var. serotina ‘Rogers’. Despite this amazing plant being native only in Alabama, it thrives in gardens well north of Chicago. This named selection was discovered in the early 1960s in the yard of University of Illinois professor Donald Rogers, and named because of its more floriferous nature, as well as its more pendulous flower spikes.
We’ve tried a number of Caryopteris x clandonensis cultivars over the years, and most fail to survive more than one of our hot, humid summers. One recent exception that surpassed all of our expectations is the amazing Caryopteris ‘Gold Crest’. Below is a mid-July image from the garden.
From the incredibly fragrant foliage to the color, to the pollinator friendly flowers, this is one amazing plant for a well-drained sunny spot in the garden. Our clumps have matured at 3′ tall x 5′ wide, so allow enough room. Hardiness is Zone 6a-9b.
With what seems to be an endless array of Hydrangea paniculata cultivars entering the market, July has turned the garden into a snow white scene. The Asian Hydrangea paniculata was first published as a new species in 1829, but was not grown in the Americas until Arnold Arboretum director, Charles Sargent brought back seed from an 1892 expedition to Japan. That original plant, now, 131 years old, measures 16′ tall x 25′ wide. I’m not saying you need to plan for your Hydrangea paniculata to reach 131 years old, but the average of a house in the US is 46 years, so logic says we should at least plant for a 50 year mature size.
Below is our clump of Hydrangea ‘Rensun’, which is marketed under a completely different name, Strawberry Sundae. The introducers of this lovely clone tout this as maturing at 5′ tall x 4′ wide, but our 6 year old specimen is already 7′ tall x 11′ wide. Based on that growth rate and the mature size of the species, I’d expect it to reach 14′ wide x 22′ wide in 50 years. It’s truly fascinating why it’s so difficult to for plant breeders to get more accurate measurements before these plants are introduced to market. One can only imagine the maintenance problems caused when you locate plants based on the size given on the plant tag, only to have the plant get 2-4 times as large as your space allows.
Back in 2018, I spotted a listing for Korean germplasm of Magnolia sieboldii on the seed exchange list for the International Magnolia Society. For those who don’t know magnolia species, Magnolia sieboldii is considered one of the most beautiful in the genus, but it’s widely known not to grow in hot, humid climates. I had actually seen this pendant-flowering species on Korea’s Mt. Sorak in 1997, but didn’t gather seed because I assumed it ungrowable. Subsequent to that trip, we would try in our garden, but we stopped after killing it on our requisite three attempts. Good sense would tell us to stop trying, but that’s not something we seem gifted with.
As with all plant breeding and selection, it’s a numbers game. If the desirable trait exists in the species, you’ll eventually find it, if you grow enough seedlings. Since there were plenty of seed available from the exchange, I reasoned that if we grew enough, perhaps one would show some heat tolerance.
I don’t remember exactly how many pounds of seed arrived, but they were promptly sown, and germination soon followed. Each time the seedlings were transplanted, only the most vigorous ones were selected. These were then grown in our research cold frame for the next year, subjected to full sun and through a typical NC summer. By the following spring, we had whittled down our selections to nine clones that had thrived in containers, and in early spring 2019, they were planted in the ground. Over the ensuing years, four passed away, leaving five. This spring, four years after planting, two clones have topped 7′ in height and are flowering beautifully, as you can see below.
There are less than 20 named selections of Magnolia sieboldii, most selected either for double flowers or blush pink tips, but none for heat/humidity tolerance. The next step will be to make a final selection which we’ll name Magnolia sieboldii ‘Southern Pearls’. Scion wood will then be shared with Magnolia grafters who will assist with our mission to propagate and share. Winter hardiness of this clone should be at least Zone 5b – 7b.
Just over a month remains before the 2023 Southeastern Plant Symposium kicks off in Raleigh, NC. This joint symposium between the JC Raulston Arboretum and Juniper Level Botanic Garden will be held on June 16, 17 at Raleigh’s North Raleigh Hilton Hotel.
We’ve got thirteen of the world’s top speakers, as our 2023 symposium focuses on the coolest woody plants on the planet. You’ll find the schedule and speakers here, where you can also register. The rare plant auction now has a worldwide following, since quite a few of the plants simply aren’t commercially available anywhere, or in some cases are very new to the trade. We hope you’ll join us for a chance to hear and meet other passionate plant people and learn about trees and shrubs.
Symposium attendees will also be able to visit both Juniper Level Botanic Garden and the JC Raulston Arboretum before and after the symposium. The lovely folks at Ball Horticulture are also funding 10 college students to attend the symposium. You can apply on line here. We hope to see you there!
Our collection of the native deciduous azalea hybrids, bred by the late Dr. Gene Aromi, of Mobile Alabama, is almost in full flower. Dr. Aromi was a professor at the University of South Alabama, who liked azaleas so much, he taught himself how to make crosses. During his lifetime, he named over 108 azaleas, many of which are just finally starting to get out in the trade. We love them for their vigor and amazing heat tolerance. Below is the stunning cultivar, Rhododendron ‘Jane’s Gold’ in the garden today.
Exochorda is a little-known monotypic genus in the rose family. The single species E. racemosa is divided into 4 subspecies, ranging primarily from southeastern China, with a disjunct population in the “Stans” (Kazakhstan, Kyrgyzstan, Tajikistan, and Turkmenistan).
Exochorda is a small shrub that flowers for us in late winter, usually starting around March 1. Pictured below in our garden is Tom Ranney’s relative new hybrid, Exochora ‘Blizzard’, which we absolutely love. This should mature around 6′ tall x 7′ wide. Zone 4a-8b.
In flower this week is Fothergilla milleri ‘Redneck Nation’. Most people have probably never heard of Fothergilla milleri, since it was just described as a new species in 2020. When a DNA analysis of the genus was completed, it showed several diploid populations previously thought to be Fothergilla gardenii were actually a new, undescribed species. Immediately after being described, it was listed as a Globally imperilled species (G2 rank).
Currently, Fothergilla milleri, which grows in swampy bog forests, is known from only 6-20 populations: a few in Coastal Alabama, one in Georgia, and a few in the Florida panhandle. This Baldwin County clone was discovered by naturalist, Fred Nation. The species was named to honor Dr. Ron Miller.
Flowering now is one of our favorite native witch hazels, the semi-dwarf, Ozark witch hazel, Hamamelis vernalis ‘Quasimodo’. This amazing gem was discovered and introduced by the late Dutch nurseryman, Pieter Zwijnenburg. I would argue that this is a far more significant introduction than his much better known Hydrangea paniculata ‘Limelight’. Our 8-year-old specimen is now 5′ tall x 5′ wide. Not only does the compact size fit in most gardens, but the density of the deliciously fragrant flowers is unparalleled in the genus.
Looking and smelling scrumptious in the garden today is Hamamelis x intermedia ‘Orange Peel’. This splendid hybrid of Hamamelis mollis (China) x Hamamelis japonica (Japan) comes from Belgium’s Kalmthout Arboretum. I don’t know that I’ve ever smelled a witch hazel this sweet.
We all love the color of leaves in fall…at least until they need to be raked. Here are a few that we enjoyed at JLBG recently.
Acer triflorum ‘Aureum’ really put on a lovely show with leaves that held on quite a while. It also colored later than most other maples.
Euonymus carnosus was quite stunning, although the effect really didn’t show up as well in the photo.
Parrotia persica is one of the last deciduous trees to color and drop in our garden. The typical color is yellow, although I’ve seem some pretty amazing red-leaf forms as well. We have not noticed much in the way of color on Parrotia persica ‘Vanessa’.
Parrotia subaequalis is the star of the genus when it comes to fall foliage, which is a brilliant purple red.
Although our row of Metasequoia ‘Ogon’ turn brown in fall, it’s still an amazing show. These are the oldest plantings of this cultivar in the US.
Raise your hand if you grow Debregeasia orientalis? This fascinating plant, which looks great now at JLBG in late October is an Adam Black, collection of a male form from Taiwan that we named Debregeasia orientalis ‘Hot Tai-male’. While we realize the mature 7′ tall x 14′ wide size of debregeasia is a bit large for smaller gardens, it’s an amazing Cousin It-shaped specimen where you have enough space. It belongs to the weedy nettle family, Urticaceae, which is why it isn’t more widely known….guilt by association. Our plant has performed wonderfully since 2014. Hardiness is Zone 7b-10b.
One of our favorite broadleaf shrubs is undoubtedly Orixa japonica ‘Pearl Frost’. Orixa is a monotypic (one species) genus in the citrus (Rutaceae) family, that’s virtually unknown in US gardens.
We are particularly enamored with this superb variegated form, brought into the US by plantsman Barry Yinger. Orixa ‘Pearl Frost’ matures at 8′ tall x 6′ wide, and we have found it to thrive in both full sun to light shade, although full sun plants require more moisture.
Lagerostroemia ‘Gamad VII’ is looking exceptional in the garden this month. This dwarf selection, sold under the invalid trade name of Sweetheart Dazzle, is a gem of a plant, and one that has actually stayed dwarf. Our twelve year old plant is 4′ tall x 10′ wide.
We’re just back from a quick outing to the Flower Hill Nature Preserve in Johnston County, NC…just a few miles from JLBG. This unique coastal plain site contains remnants of species more common in the NC mountains, nearly 5 hours west. The top of the bluff is a small stand of enormous Rhododendron catawbiense, while along the bottom of the hill is a bank of the deciduous Rhododendron canescens.
In the mid-slope area, we found Cypripedium acaule (pink ladyslipper orchid), just waiting to be photographed. Sadly, it’s one of the most difficult species to transplant, so just enjoy these in situ when you find them.
There were beautiful masses of the evergreen groundcover galax, growing on the eastern slope.
It was particularly great to see the Asarum vriginicum in full flower. True Asarum virginicum is rarely seen in cultivation, and the diversity of flower color was outstanding.
Edgeworthia chrysantha ‘Snow Cream’ is a 2000 Juniper Level Botanic Garden/Plant Delights introduction that has proven to be one of our most popular introductions. We made the original selection from a group of seed-grown plants, imported from China by Canada’s Piroche Plants in the late 1990s. We were drawn to this seedling because of the particularly large flowers, and large leaves that reminded us of a plumeria. Let me be clear that all Edgeworthia chrysantha seedlings are nice, but there is certainly a significant difference between flower and leaf sizes of seed-grown plants.
Below are photos from our winter open nursery and garden days this year, where our garden specimens never cease to amaze visitors with both its sweetly scented flowers and amazing floral show. Sadly, no matter how many we propagate, it never seems to be enough to meet the demand. A more open site results in a much better floral show. Hardiness is Zone 7a – 10b.
Flowering this week at JLBG is the amazing cherry red Hamamelis japonica ‘Tsukubana-kurenai’, also known as Shibamichi’s Red witch hazel. This gem was selected by legendary Japanese nurseryman, Akira Shibamichi, who also introduced Metasequoia ‘Ogon’. We were blessed to have Mr. Shibamichi visit JLBG back in the 1990s.
Few people know the fascinating native shrub, Dirca palustris. It’s little wonder it gets overshadowed by showier members of its family, Thymelaeaceae, which includes the likes of Daphne and Edgeworthia. Our 6′ tall plant is flowering alongside a large edgeworthia, and rarely gets noticed by visitors.
Dirca palustris, the plant, is actually widespread across Eastern North America, with a range from Canada to Florida, where it thrives in slightly moist, acidic soils. It’s often known as leatherwood, due to its thick, but very pliable branches, which have been used by Native Americans for making rope as well as baskets.
There are three other less poorly known dirca species…if that’s possible. We grow the rare Dirca decipiens from Kansas/Arkansas, but have not yet tried D. occidentalis from California, or D. mexicana from Mexico.
The genus takes its name from the Dirce in Greek Mythology, who bit the big one while tied to the horns of a bull….a truly sordid story. The specific epithet “palustris”, lacks the fascinating story of the genus, but only means that the plant naturally lives in very wet sites. Winter hardiness is Zone 3-9.
In full flower this fall is Disanthus cercidifolius. Ok, so full flower on a disanthus may not seem too exciting to the petunia and pansy crowd, but plant geeks find these flowers pretty darn cool. We’d nearly given up on growing this witch hazel relative after finding in our first few attempts that it has zero heat tolerance. It wasn’t until we obtained a plant from a Chinese population (Disanthus cercidifolius ssp. longipes) of the better known Japanese native, that we realized there is a form we can grow, and grow well. Not only does the Chinese form have heat tolerance, but it also thrives in full sun. The specific epithet “cercidifolius” means foliage like a cercis (redbud).
The beauty berries are looking quite good this fall in the garden. Two forms of Callicarpa americana are a bit unique. The white fruited Callicarpa americana ‘Lactea’ has been stunning, as has the pink-fruited Callicarpa ‘Welch’s Pink’, discovered by Texas plantsman, Matt Welch.
A fairly new beauty berry to cultivation thanks to the US National Arboretum is the Chinese Callicarpa rubella. Over the last few years, we have fallen in love with this amazing plant. This is our garden specimen planted in 2015. The new foliage is spring is tinged black…a nice touch!
Calycanthus ‘Burgundy Spice’ is looking so great in the garden at JLBG this fall…right before it strips down for the winter. We love this exceptional purple-foliage selection of the native Sweet Betsy, discovered and introduced by our friends, the Hesseleins’ of Pleasant Run Nursery in NJ.