One of our favorite ferns, known as Cat’s claw fern, is putting on quite a show this fall. Onychium japonicum is a plant I’d never met until a 1996 expedition to Yunnan, China. Although it was a bit depauperate in the wild, the potential I saw, was far exceeded by its garden performance. We now grow four different wild collections, all of which have somewhat similar growth and appearance.
We have found Onychium japonicum to thrive in everything from light shade to full sun, even in our brutal summers. The foliage is tardily deciduous, meaning it usually looks great here until early-mid January. The plant spreads via rhizomes, but the spread is not fast, so it’s easy to reign in, if your patch gets too wide. We think the incredible texture and ease of growth makes this a fern that should be in every garden where it’s growable. Hardiness Zone 7a-9b, at least.
Athyrium shearei is a fascinating fern, given to us many years ago by fern guru, Dr. John Mickel. We’ve yet to offer it because we’re not sure if anyone would purchase it since some folks may think the dark central veining may look like something is wrong with the plant…which it is not. This deciduous fern native to China, Korea, and Japan makes a slowly spreading patch, and is hardy from Zone 5-8. Mature height is 15-18″ tall. What do you think?
One of my favorite plants when I strolled through the woods as a young child was resurrection fern, Pleopeltis michauxiana. If the Latin name sounds unfamiliar, it was originally published in 1939 as a member of a different fern genus, Polypodium polypodioides var. michauxiana. It’s natural distribution range is quite large, from West Virginia south into Central America.
From the time I first saw this fern, nearly 60 years ago, I found it fascinating that this native evergreen fern could grow on both trees and rocks, without being rooted into the ground. Through the years, I’ve tried to cultivate it many times, both in containers and in the garden, failing repeatedly.
Finally in 2004, we took a small piece and glued it to a water oak in the garden using the commercial outdoor adhesive, Liquid Nails. Below is that same plant, almost 20 years later at JLBG. When the weather dries, the clump quickly shrivels and looks dead, only to revive when rain arrives or the garden is irrigated. We’re still trying to figure out how to get this into the nursery, so we can share it more widely.
We’ve been fortunate to grow a huge number of hardy garden ferns through the years, but it’s hard for any to top the amazing Pleopeltis lepidopteris, to which, we’ve given the common name, Brazilian hairy sword fern.
Below is a patch at JLBG, composed of three individual clumps, looking great, despite the ravages of summer. This sun-loving lithophytic (rock grower) also grows fine in well-drained soils. In habitat, it hails from the sandy, acidic coastal (restinga) habitats in southern Brazil (Rio Grande du Sul). Our plants came from our friends at the former Yucca Do Nursery, who made a beach front collection in Brazil in 2012. It doesn’t appear that fern had been in cultivation prior to that time.
The 18″ tall x 2″ wide, rigidly upright fronds emerge covered in thick silver hair, to which I can now relate. As the fronds age, the hair thins and the green leaf surface becomes more visible. Pleopeltis lepidopteris spreads slowly from surface rhizomes. We’ve grown this evergreen Pleopeltis in our rock garden since 2012, where it has thrived even through winter temperatures of 7 degrees F. Hardiness Zone: 7b to 9b, at least.
We have long loved the evergreen, tri-lobed, Asian (China, Korea, Japan) epiphytic fern, Pyrrosia hastata. Our favorite clone, pictured below, is one we purchased many years ago from an on-line Japanese plant auction, and subsequently named Pyrrosia ‘Storm Watch’, due to its dark black central leaf vein. Unlike the rhizomatous Pyrrosia lingua, Pyrrosia hastata forms a very tight clump, and is extremely adaptable to growing both epiphytically as well as in the ground, as long as the soil doesn’t stay too moist.
Those who were heavily into gardening in the early 1990s probably remember the micro-mail order nursery, The Wildwood Flower, run by the unique and colorful NC plantsman Thurman Maness. While Thurman’s nursery lasted less than a decade in the mail order realm, his impact in the horticultural world continues though his many plant introductions.
Thurman’s probably best known in the plant world for his lobelia hybrids, as demonstrated by his 1990 catalog which listed 20 different lobelias. We’ve offered a number of Thurman’s lobelia hybrids through the years, including varieties like ‘Rose Beacon’, ‘Ruby Slippers’, and ‘Sparkle deVine’, and still carry one of our personal favorites, Lobelia ‘Monet Moment’.
Thurman was also a very successful fern breeder, and many of our favorite ferns today are some of his hybrids like Athyrium ‘Wildwood Twist’ and I still rank his Athyrium ‘Ocean’s Fury’ as the finest fern hybrid ever created.
Thurman’s old catalogs also included little known, but garden worthy natives like Scutellaris serrata and the Federally Endangered Silene catesbiae (polypetala). When I first visited back in the early 1990s, Thurman was running his own tissue culture lab, where he was both producing plants as well as conducting ploidy manipulation for breeding..
So, what’s Thurman doing today. At age 87, he’s still working in his garden and propagating plants, which he occasionally sells on site at his Pittsboro home. He tells me that he’s ramping up production because of the new 400 acre development just a few miles away…he’s determined that they all need hydrangeas.
He also still runs his antique business, now from an antique mall in nearby Siler City. When he goes out on the town, he often does so as his alter ego, Sparkle deVine, as you can see in this recent photo below. JLBG/PDN salutes a brilliant plantsman for a horticultural life well-lived.
One of the most amazing ferns in our collection is the little-known Chinese Adiantum fimbriatum. Closely allied to the hugely popular Adiantum venustum, the fimbriate maidenhair fern is actually a far better grower in our hot, humid climate, despite coming from elevations from 9,000-12,000′.
Despite the impending flooding late last week, Patrick, Zac, and I took off to the mountains of western South Carolina for a few days of botanizing. Despite the monsoon-like rains, we managed to visit seven amazing sites. Below is a highlight.
One stop was at a giant granitic outcrop. The rocks are covered in an array of mosses, lichens, and other associated flora, most growing in shallow pockets or organic debris that alternation from inundated to bone dry for months.
Large patches are covered with the colorful, 1″ tall, annual sedum, Diamorpha smallii, commonly known as Elf orpine.
Diamorpha smallii
Another site also had large granite flatrocks, but with a complete different flora. Here, two dryland ferns, Cheilanthes lanosa and Cheilanthes tomentosa formed large patches, along with the amazing Selaginella tortipila.
The more shaded slopes were filled with amazing clones of the dwarf painted buckeye, Aesculus sylvatica, which at this site, mature at only 3-5′ in height. In most other area, the same species matures at 10-20′ tall. The flower colors here ranged from peachy yellow to screaming orange red.
Aesculus sylvatica dwarf forms
One of our next stops was an amazing watershed where, Shortia galacifolia grows by the acre, carpeting the mountain side. This is the world’s largest population of this amazing native. We even found it growing epiphytically on a rock, perched in the middle of a stream.
Shortia galacifoliaShortia galacifolia
The native Micranthes micranthidifolia grew along the moist stream banks. This is the first time I’ve seen this, since I first purchased the plant back in 1995 from the former We-Du Nursery. In that case, I killed it, before getting it planted.
Micranthes micranthidifolia
Another plant I’ve killed in my previous attempt was the native climbing fern, Lygodium palmatum. Here, it grew with the easy-to-grow Christmas fern, Polystichum acrostichoides.
Lygodium palmatum
The difficult to grow Asarum heterophyllum was scattered throughout our several mile trek, almost all plants were the solid green leaf form.
Asarum heterophyllum
Far easier to grow is the native Hydrangea radiata (formerly known as H. arborescens var. radiata), with its shimmering white-backed leaves.
Hydrangea radiata
As we walked along the towering cliffs, the red fruit adorning the carpets of partridge berry, Mitchella repens glistened in the rain.
Mitchella repens
Several patches of mayapple, Podophyllum peltatum had some of the largest foliage that I’d ever seen, measuring 1′ in width.
Podophyllum peltatum
Not far away we saw some of the most strikingly patterned form of Pachysandra procumbens we’ve ever seen.
Pachysandra procumbens
We almost got through the entire trip without finding a single variegated or colored foliage mutant, when not far from the parking area, we spotted a streak sport on Kalmia latifolia.
Kalmia latifolia streaked branch
Below is our incredible, but soaking wet, botanizing team (l-r) Adam Black, Bartlett Arboretum, Zac Hill, JLBG, Patrick McMillan, JLBG.
We always get excited when the Osmunda regalis fronds begin to unfurl in the bog garden at JLBG. Here are some images from this week, showing the new fronds. The rosy emerging growth is the sterile part of the fern frond, while the green growth at the top is the fertile part, which will produce the spores (fern seed). Hardiness Zone 3a-9a.
Osmundal regalis
Below is another clump nearby, that emerges about a week earlier, and as such, is further along in opening.
Osmunda regalis
Below is our hybrid, Osmunda x japalis ‘King Kong’, a cross between the American native Osmunda regalis and the Japanese native, Osmunda japonica. Unlike the 4-5′ tall Osmunda regalis, Osmunda japonica is much smaller (to 3′ tall), emerges 1-2 weeks later, and has dimorphic fronds—the spores are on different stalks than the foliage. Our hybrid has dimorphic fronds like the O. japonica parent, emerges later, but is much larger to 7′ tall.
The Dryopteris kinkiensis is still looking fabulous in the garden as we inch closer to spring. This little-known Chinese native fern was first brought into the country as spore by plantsman Hans Hansen in 2005. It is also native to Japan, Korea, and Taiwan. The name was originally published for the material in Japan, named after the Kinki region. The foliage is a very glossy dark green with a nearly plastic texture. We estimate hardiness to be zone 7a-9b, but we could be greatly underestimating its potential in that regard.
We have long been enamored by the elegant, evergreen fern, Polystichum neolobatum, but have failed countless times with the commonly sold material in the horticultural trade. It was not until we grew spores from a Hans Hansen Chinese collection from 7,000′ elevation in China’s Sichuan province that we met with success. Below is a specimen from that trip, taken here at JLBG last week.
As is the case with so many commercially sold plants, their origin is lost. While the commercial material of Polystichum neolobatum may be fine in the cool temperatures of the Pacific Northwest, that is simply not the case here in the hot, humid Southeastern US. This species has a wide native range from the Himalayas all the way to Taiwan, where it can be found from 4,000′ elevation to 10,000′ elevation. Both elevation and origin location matter when determining the adaptability of many plants. We are finally getting good spore set, and hope to be able to make this form available through Plant Delights in the near future.
The cold and raw weather of late autumn and winter provide the perfect opportunity to sit down with the dissecting scope and put our ferns through the identification mill. Often gardens and nurseries receive a plant into their collections from an exporter or collector who has put their best guess on the identification. After many years in cultivation, we realize what we thought was the right species name for our specimens is incorrect. Today’s nasty weather provided the opportunity to examine, in detail, one of our favorite evergreen fern groups – Dryopterissection Variae.
These firm-leaved evergreens produce thick-textured, durable, medium-sized fronds of varying shape but all display a noticeably longer basioscopic pinnule (that’s fancy talk for the lowest, innermost segments of the divided leaves). All members of the section that we have grown have proven to be very adaptable to our hot, humid summers and unpredictable winters if grown in shade or partial shade in moist woodland garden conditions. The fronds tend to burn if they receive too much light. They are late risers in the spring often not producing a new flush of leaves until late spring or even early summer.
At the beginning of the day, we started with 8 accessions of Dryopteris varia, 2 accessions of Dryopteris bissetiana, 6 accessions of Dryopteris formosana, one accession of Dryopteris saxifraga and a couple of unknowns. From these numbers you would expect that the one plant we would know best would be Dryopteris varia.
Dryopteris bissetiana comparison
Well…it turns out all the plants we had received or had identified as D. varia were actually representative of other taxa. If you’ve never tried keying ferns using The Flora of China or The Ferns and Fern Allies of Taiwan, you would have no idea just how difficult a process this is. The floras of these areas are notoriously difficult to use and often contradictory or difficult to assess using illustrations or pictures (yes even plant taxonomists google names to find images). Very quickly we became intimately familiar with the nature of the stipe and rachis scales, frond outlines, and disposition of the vestiture (yeah you think that sounds easy, right?).
We found most of our collection was actually composed of Dryopteris bissetiana, which are mostly from collectors who sent us tentatively identified wild-collected material. The majority of these were from Sichuan in China, however one very beautiful, deep green and glossy selection that is only half the size or less of the others was Tony’s collection in Korea, and has tentatively been identified as Dryopteris saxifraga. All of these are remarkable garden plants, but we are very excited to some day offer the choice dwarf from Korea which we have named ‘Cheju Dwarf.’
It was a pleasant surprise to find that our collections of Dryopteris formosana were correctly labelled, but we weren’t prepared for there to be two distinctly different looking plants represented in our garden that are the same species.
One of these is the plant that has been shared among fern enthusiasts for some time that is the typical sexually reproducing diploid. The other is an apogamous triploid that looks like a completely different species. In a diploid (like you and I) the pairs of chromosomes uncouple and one copy of each goes into making the male and female gametes.
Dryopteris formosana forms
Thus, each gamete has only one set of each chromosome (haploid) and when combined with those from the complementing sperm or egg results in another diploid. Plants sometimes have a mistake in their cells that lead to the production of gametes with twice as many chromosomes as they would normally have and when such tetraploid plants breed with a diploid the result is a gamete with 2 copies of each chromosome combining with a gamete with only one—thus triploid. In your average plant this triploid is a dead end for reproduction by seed or spore because they have an uneven base number 3—which can’t be divided into an equal number of chromosomes, so it is sterile.
Dryopteris formosana comparison diploid left triploid right
This triploid avoids the curse of having an uneven number of chromosome pairs by avoiding sexual reproduction and producing spores that will result in new plants without the traditional interplay of sperm and egg on a germinated gametophyte (yes apogamy in ferns is still legal in all states and countries). We were puzzled when two very different looking ferns keyed to the same species. Everything that was in the key matched. The bullate hairs, the shape, the color, the basioscopic pinnae and the overall shape.
Our taxonomist, Zac Hill, very quickly uncovered a recent paper by Kiyotaka Hori, et al (2017) which explained and beautifully illustrated our conundrum. The triploid produces a wider, far more pentagonal frond with a less erect nature in the way the blade is held, and a deeper green, highly pleasing color—now that’s pretty darn cool! This new discovery we have named ‘Yushan 2 X 4.’ A new plant for us all to grow in the years to come and now you know why we chose the name diploid (2) X tetraploid (4).
Dryopteris formosana triploid
Now that we realize we grow seven different forms of Dryopteris bisettiana, each collection will be given a cultivar name, which will refer back to their specific origin and uniqueness.
Every day brings discovery when you manage a collection of 30,000 taxa but one thing we know for sure, these are amazing, well-behaved, slow growing woodland plants that are the essence of what makes Juniper Level Botanic Garden so amazing.
Patrick McMillan, director of horticulture and gardens
Literature cited:
Hori, Kiyotaka, L. Kuo, W. Chiou, A. Ebihara and N. Murakami. 2017. Geographical distribution of sexual and apogamous types of Dryopteris formosana and Dryopteris varia (Dryopteridaceae) in Taiwan. Acta Phytotax. Geobot. 68 (1): 23-32.
Nurses and plant taxonomists are among the few fields in which you would run into the term, anastomosing veins. Having been in the plant world all my life, I had never even run into the term until trying to key our some bamboo ferns in the genus, Coniogramme, almost a decade ago. It turns out that to distinguish between species, you need to determine if the spore patterns on the back of the leaf have an anastomosing or parallel vein pattern. Anastomosing veins are those which diverge and reconnect forming a pattern like a snake skin. We’ve grown quite a few ferns, but none have the amazing vein patterns of coniogramme. Below are the leaf backs of Coniogramme japonica in fall.
Coniogramme japonica – spore pattern on leaf backConiogramme japonica – spore pattern close up
Adiantum capillus-veneris ‘Bermuda Run’ is looking exceptional in the garden this fall. Actually, it looks exceptional most of the year for us. Until the temperatures drop below 12 degrees F, this amazing fern remains evergreen. This fern has a huge native range, being found on every continent except Antarctica.
Adiantum capillus-veneris, along with a couple of pteris fern species are often found growing in mortar cracks in many of the Southeast coastal cities and adjacent tropical islands. It is thought that some of these populations may have been spread along the early trade routes. This particularly dense form is our collection from the mortar walls on Bermuda. The same species is native to North Carolina, but only in a solitary population. Winter hardiness is Zone 7b-10b.
One of our favorite ferns is the Lady fern hybrid, Athyrium ‘Ocean’s Fury’. Created in Pittsboro, NC by plantsman Thurman Maness, this patented gem was offered for years through wholesale channels, but sales were not strong enough, so the sole producer discontinued it. So often, great patented plants suddenly become unavailable if sales don’t warrant.
In Europe, any grower can petition the PVR office to request permission to propagate such protected plants, but no such program exists in the US. Fortunately, Thurman has generously granted us permission to propagate his amazing introduction and make it available. That said, division is a very slow way to make ferns available, but since this hybrid between Athyrium filix-femina and Athyrium nipponicum is sterile, it’s our only option.
If you’re a nursery, and you’d like to offer ferns, the plants at your disposal are somewhat limited. A large majority of ferns sold in America are still sadly dug from the wild. When you see a catalog listing primarily these ferns together…usually an very inexpensive prices, you can be pretty much assured they were dug from the wild: Osmunda regalis (royal fern), Osmunda cinnamomea (Cinnamon Fern), Polystichum acrostichoides (Christmas Fern), Matteuccia Matteuccia struthiopteris (Ostrich fern), Adiantum pedatum (Maidenhair fern), Athyrium filix-femina (lady fern), and Onoclea sensibilis (Sensitive Fern). These ferns are often sold bareroot, to save the nursery the expense of having to pot the collected plants, many of which are so large, they won’t fit in small containers.
The other majority of ferns in the market are produced by tissue culture, either by a couple of labs in Florida, one in Texas, and one in Holland. Without the amazing work of these labs, the fern selections available to homeowners would be limited to the wild collections. Even with their amazing work, these labs must focus on well-known ferns that sell in very large numbers.
While we make use of the lab offerings, we also made a commitment over 30 years ago to grow many of our own ferns from spores. Outside of a few small fern specialists, there are few nurseries who grow their own ferns from spores, since this is the most costly and time consuming option. The reason we do this is so that we can offer fern species and selected forms that are otherwise unavailable.
Below is a quick summary of how the process works. Fern spores (fern equivalents of seed) are collected through the summer, and are dried in paper envelopes until they separate from the foliage. They are then sown in pots with potting soil that is sterilized here, and then sealed in ziploc bags. The spore takes from 1 month to 6 months to germinate. Once the spores germinate, they are ready to have sex…a process that is reversed from more modern evolved flowering plants.
To assist the ferns have sex, we gently add water to the newly germinated sporelings, since ferns (other than desert ferns) only have sex while they are swimming. The water is swirled around to mimic the feel of a whirlpool, then the bags are then resealed, and put in the dark where they are subjected to a near constant montage of Barry White music.
Within a few weeks, tiny fern fronds begin to emerge. At this point, the ziploc bags are opened to allow the humidity to equalize with the ambient air. After another couple of weeks the pots are removed from the ziploc bags. If the spore were viable and cleaned well without contamination, and if germination was good, there will be up to several hundred plants per pot.
After a few weeks, the sporelings are transplanted into a cell pack flat. Here they grow out for another few months until they are ready to be planted into our 1 qt. pots, in which they will be sold. In all, it’s about an 18 month process, and a good bit of labor. We’re really quite passionate about our fern collection at JLBG, which the visiting British Fern Society declared one of the largest/most diverse in the world. We hope you find the results worthwhile.
Indeed the old proverb about a rolling stone is correct, but a stationary stone, especially in the water, gathers all kinds of amazing things. This rock in one of our garden streams has not only gathered moss, but several young maple trees, a carex, a couple of sanguinaria (bloodroot), and a handful of various ferns. Isn’t nature just grand if you stop long enough to pay attention.
