In our hot, humid climate, we really struggle with keeping most cultivars of Caryopteris x clandonensis alive for very long. A lovely exception in our trials has been Caryopteris ‘Gold Crest’, a recent introduction from the plant breeders at Ball Hort. Here is our three year old clump in the garden this week. The foliage is deliciously fragrant…more so than any other caryopteris we’ve ever grown, and the native bees find it incredibly attractive. We’ll be adding this to the new Plant Delights catalog in January. Winter hardiness is Zone 6a-9b.
With the trend green mulch (i.e. groundcovers), we continue to trial a number of new introductions that fit the bill. One of the top performers continues to be Sedum ellacombeanum ‘Cutting Edge’ PP 28,926. This 2016 Brent Horvath introduction has thrived in both sun and light shade, making a perfect ground-hugging mat. Despite being a top performer, sales were miserable when we offered it a few years ago. We’re not sure why it sold so poorly, but we now have some lovely drifts in the garden.
We always look forward to elephant ear evaluation day at JLBG, which was recently completed.
Each year, Colocasia breeder, Dr. John Cho flies in from Hawaii to study and select from our field trials of his new hybrids. This year we were joined by Robert Bett, owner of the California-based plant marketing firm, PlantHaven, who handles the Royal Hawaiian elephant ear program. The JLBG trials consist of all named colocasia introductions growing alongside Dr. Cho’s new hybrids created the year prior.
JLBG staff members, Jeremy Schmidt and Zac Hill spent most of the morning working with Robert and John on the time-consuming evaluation process.
After lunch, Jim Putnam from Proven Winners, joined us to see which remaining plants struck his fancy for potential introduction into their branded program. As you can see, lots of amazing plants didn’t make the final cut, which is necessary, since we’ll need more room for the new selections.
Plants selected for introduction are then sent to a tissue culture lab to be produced for the next step, which is grower/retailer trials. If these are successful, and the plant can be multiplied well in the lab, the plants are scheduled for retail introduction.
Hopefully, by now, most folks are familiar with our 2020 top selection, Colocasia ‘Waikiki’, which hit the market this year. There are more really exciting new selections in the pipeline, but we can’t share photos of those quite yet…stay tuned.
Looking particularly lovely in the late summer garden is Fatsia japonica ‘Murakumo Nishiki’. This irregularly gold variegated form of the typically solid green tree ivy is a star in the light shade garden. This evergreen gem is a great way to add a spot of color in the woodland garden year round. Hardiness is Zone 7b-10b.
We’ve long been fascinated by Amorphophallus konjac ‘Shattered Glass’, an unstable variegated cultivar, developed by plantsman Michael Marcotrigiano. Some years, the foliage emerges solid green, other years with a small bit of sectoral variegation, and this year with a fully variegated leaf.
I’m more and more impressed with Hosta ‘Miss America’ each year. Not only is this white-centered hosta amazingly vigorous, but it has one of the finest floral shows we’ve ever seen on a hosta. The steel rod-like upright flower stalks on our plant have reached 4′ tall, but as the plant grows larger, they will eventually top 6′ in height. Not wind, rain, or post office vehicle can knock down these super sturdy stalks, and the great show they provide for weeks. Our plant is 100′ from our back porch, and it shows up like a floral beacon even from that distance.
Here’s a fun textural image from the woodland garden, featuring Hydrangea quercifolia ‘Little Honey’, Farfugium japonicum ‘Aureomaculatum’, and Athyrium ‘Ocean’s Fury’. Off to the left side are three more ferns, Dryopteris x celsa, Adiantum capillus-veneris, and Ctenitis subglandulosa.
We love the spineless Agave bracteosa ‘Stingray’ in the garden. We’ve had these dotted throughout the garden since 2017, and so far, with good drainage, they’ve handled our winters quite well, which is certainly not normal for a variegated century plant. This particular species prefers part sun to light shade. Hardiness is Zone 7b/8a and warmer.
Here’s a photo this week of one of our favorite North American native plants, Juniperus horizontalis ‘Copper Harbor’. This would certainly add significant year round color interest to any native plant garden. In our trials, this is far and away the best of the golden Juniperus horizontalis cultivars. We offered this selection for a couple of years, but there seemed to be little interest.
Looking lovely today is the amazing Agave x romanii ‘Shadow Dancer’. This fascinating agave is a manmade hybrid between two Mexican species, Agave filifera and Agave mitis. Not only is it a hybrid, but this selection has a fascinating variegation pattern that’s not seen on any other century plant. The new growth emerges ghostly cream with a muted green border. As the leaves age, they green disappears and the leaves become pure parchment white. Despite the seeming lack of chlorophyll, Agave ‘Shadow Dancer’ has amazingly good vigor and doesn’t burn in full sun. This has potential winter hardiness for Zones 8b and south, but needs more trialing to know for sure. In other climates, it’s a great container specimen.
This spring, one of our flats of Rohdea japonica seedlings turned up with an inordinate number of variegated seedlings. In a flat of approximately 1,000 seedlings, we typically expect 3 – 10 variegated offspring, when the parent plant has white streaking in the middle of the leaf (L2 layer).
All of the variegated seedlings were removed and potted individually last week…all 300 of them. It will be fascinating to see what unique forms result.
We ran across this fascinating reticulated leaf form of the US native (every state east of the Mississippi) groundcover partridge berry (Mitchella repens) last week, when tromping through the woods near JLBG. We’ve taken a few cuttings that will be evaluated here for garden performance. In 60 years of botanizing, this is the first form we’ve seen with this nicely patterned foliage.
Here’s a garden shot at JLBG, using a good bit of gold foliage in addition to flowers. Left to right: Viburnum dentatum ‘Golden Arrow’, Sinningia ‘Amethyst Tears’, Baptisia ‘White Gold’, Canna ‘Tama Tulipa’, Lysimachia nummularia ‘Aurea’ (groundcover), Hibiscus ‘Holy Grail’ (purple), Spirea thunbergii ‘Ogon’, Trachycarpus fortunei (palms).
Below are two variations on a theme…calla lilies in the garden. Here is Zone 7b, both are reliably winter hardy in the ground.
The striped-leaf selection of the winter-blooming South African native, Zantedeschia aethiopica ‘African Gold’ has looked fabulous all spring, where we have it planted in a seep, which gets full sun for 3-4 hours in the morning.
Zantedeschia ‘Picasso’ is a hybrid, created using several of the summer-flowering South African native calla lily species. Here it is in our garden in mid-June, where it gets 4-6 hours of sun daily, and the soil stays reasonably moist.
Solomon’s Seals comprise several genera of woody perennials, but the common name is most commonly associated with the genus, Polygonatum in the Asparagus family. It seems hard to imagine, but the Asparagus family now includes many popular garden plants including its namesake Asaparagus, but also hosta, agave, liriope, ruscus, and yucca.
The genus Polygonatum is native through much of the world, although the center of distribution is in Asia. We’ve been collecting these amazing woodland perennials for years, and now have a collection of over 380 different taxa. Here are a few from this week in the garden.
Polygonatum mengtzense is a dwarf, rarely cultivated species from North Vietnam.
The dwarf, glossy-leaf Chinese Polygonatum nodosum just oozes elegance.
When you run out of species to grow, you start creating hybrids. This is our new selection of a cross of the giant Polygonatum martinii and the more compact, Polygonatum falcatum. We’ve named this clone Polygonatum x marcatum ‘Winsome Wonder’
Polygonatum odoratum ‘Chanticleer’ is a superb, large-leaf form of the Asian Polygonatum odoratum that I spied at Chanticleer Gardens, and they kindly shared in 2006. Hopefully, we’ll finally have enough to share next year.
Polygonatum odoratum ‘Angel Wings’ (aka: ‘Carlisle) is a superb form of Polygonatum odoratum from Massachusetts plantsman, Roy Herold. This gem grows in both half day sun as well as shade.
Over the last few weeks, I’ve been working on a plant survey of a local woodland area of about 30 acres. The low, moist areas are filled with Arisaema triphyllum, (Jack-in-the-pulpit) which is quite common in our area. The first image is what is typical for the species.
I’ve been studying patches of Jack-in-the-pulpit for well over 55 years, always looking for unusual leaf forms that showed any type of patterning. Until last month, I’d never found a single form with atypical foliage. That all changed with my first trip to this local site, where so far, I have found several dozen forms with silver leaf vein patterns. Up until now, there are only two pattern leaf forms of Arisaema triphyllum in cultivation, Arisaema ‘Mrs. French’ and Arisaema ‘Starburst’.
Each patterned leaf clone varies slightly as you would expect within a population including both green and purple stalk coloration.
While I’d never found any true variegation prior to this, I had found plenty of transient leaf patterning caused by Jack-in-the-pulpit rust (Uromyces ari triphylli). This site was no exception, with a number of plants showing the characteristic patterning. If you find these, turn the leaf upside down and you’ll see the small orange rust pustules.
While these may seem exciting, the pattern are not genetic and will disappear without the fungus. Fortunately, this rust can be cured by cutting off the top of the plant and discarding it where the spores can not spread via the wind. Infected plant should be fine, albeit smaller next year. The susceptibility of Arisaema triphyllum to jack-in-the-pulpit rust varies with genetics. Of the tens of thousands of plants I observed at the site, less than 10% were infected with the rust.
Arum are a fascinating genus of hardy aroids, known by most gardeners from a single southern European species, Arum italicum. The most popular cultivar of Arum italicum is Arum ‘Marmoratum’. The key to enjoying arums is to not let the seed drop everywhere, since you can get easily get over-arumed. Flowering season is now, followed by seed season. Each seedling has a different pattern from the original, so it’s a personal preference whether to remove seed or not.
Arum apulum is a little-know species that is rarely seen in cultivation, native only to a small region of Southern Italy. Our flowering plants in the garden now are from a wild collection made by a plant explorer friend.
Below is an interesting hybrid between Arum italicum (central to southern continental Europe) and Arum dioscorides (Mediterranean). Arum italicum has patterned leaves, but solid green flowers. Arum dioscoridis has solid green leaves and spotted flowers. The hybrid, Arum ‘Chui’ is an introduction from UK plantsman John Grimshaw. We added the notospecific (hybrid) name Arum x diotalicum. These hybrids have both spotted/speckled leaves and flowers.
Carex conica ‘Hime’ has been in horticultural commerce for many decades, and remains a superb woodland garden sedge. The evergreen species Carex conica is native throughout Japan, where it occurs in woodland conditions. This variegated selection that goes by an array of names such as ‘Snowline’ and ‘Marginata’, but Carex conica ‘Hime’, which translates to “princess” seems to the the correct cultivar name. The tight 10″ tall x 20″ wide clumps of narrow white-edged leaves are topped with this fascinating floral show for us in early March. In 35 years of growing this, we have yet to see a single garden seedling.
Trillium cuneatum ‘Oconee Gold’ is a rare gold-flowered selection of the typically purple-flowered southeastern toadshade. We found our original plant of this in Oconee County, SC, and have propagated them from seed since that time. If we keep the yellow-flowered plants isolated from purple-flowering clones, we have more than 50% that reproduce with yellow flowers. The time from seed to flower is usually five years. Winter hardiness is Zone 5a-8b.
We treasure any plant that makes a great woodland groundcover, and are particularly smitten with the ophiopgon (mondo grass) and liriope (monkey grass) selections. We currently grow over 120 different ophiopogon accesions including quite a number of wild collections, at JLBG…see what a touch of OCD does for you. We’ve grown Ophiopogon ‘Comet’ since 1997, and love it for its white striped foliage and well-behaved growth habit. Hardiness is Zone 7b-10b.
Here are a couple of images this week from the garden of our older clumps of Cyclamen hederifolium. For garden areas that are dark and dry, where nothing else grows, cyclamen are your best bet. Of the plants below, one is at the base of a cryptomeria and the other at the base of a pine. Although they flower from August until Christmas, the winter foliage is just hard to beat. Hardiness is Zone 4a-8b.
Asarum hypogynum ‘Artist’s Palette’ is in full flower here at JLBG in late January. Despite being first published in 1915, this little-known species is very poorly represented in ex-situ plant collections worldwide. Our clone is a division from a wild plant we brought back from our 2008 botanical expedition to Taiwan. The foliage on this species is some of the largest in the entire genus. For us, Asarum hypogynum starts flowering in late summer and continues most of the winter. We are working to eventually be able to share this with other collectors. Hardiness is Zone 7b and warmer.
Asarum minus ‘Cupid’ is one of our heavily silver patterned selections of our native wild ginger. When cold weather arrives, the evergreen leaves take on a lovely purple cast. This is an excellent clonal selection we made in 1994 from a construction site, and one we hope to offer in the future though Plant Delights Nursery.
One of our favorite winter hardy (Zone 7b) century plants is the non-spiny Agave bracteosa ‘Stingray’. Here is one of our garden specimens this week, which has been thriving in the ground since 2016. Unlike most agaves, which prefer full sun, Agave bracteosa is better in part sun (full sun for only a few hours during the day). Agave bracteosa ‘Stingray’ is also a fairly slow grower that only produces a few offsets. A mature rosette will top out around 15-18″ tall x 2′ wide. We love the unique texture, which differs from all other agaves.
Bambusa multiplex ‘Alphonse Karr’ is looking so hot this winter with its amazingly striped canes. This clumping bamboo is usually grown as a die-back perennial here in Zone 7b, since it goes to the ground when temperatures drop below 10 degrees F. Because we’ve had three mild winters, we are once again able to enjoy the amazing striping of the canes. I did get a chuckle last year, when I saw Bambusa multiplex show up on an invasive species list for North Carolina. As I explained in my letter to the group, Bambusa multiplex is first and foremost, a clumping species. Secondly, all truly invasive species (which invade functioning natural ecosystems, displacing natives and causing economic harm once population equilibrium has been reached) must be able to spread by seed, and bamboo clones only flower once in 100 years, and then die. It’s these emotionally driven lists, without any basis in facts or real science, that makes so many of the invasive lists a farce, and sadly untrustworthy.