Although the native Ostrich fern, Matteuccia struthiopteris ‘The King’, goes winter dormant, the fertile fronds remain upright and attractive all winter. Here, we have it growing among the evergreen Solomon’s Seal, Disporopsis pernyi. This site is quite dry, compared to it’s normal habitat of wet swamps.
The typical holly fern, Cyrtomium falcatum, is considered fairly reliable in Zone 7b, but no further north. The oddball is the coastal form, which grows on the coast of both Japan and Korea. We received the plant shown below in 2005, as Cyrtomium falcatum var. maritimum, which our taxonomy staff tells me, isn’t a valid name. According to Patrick and Zac, the Japanese coastal material is correctly called Cyrtomium falcatum var. littorale, but there is no mention in the literature they’ve reviewed of the same coastal form occurring off Korea.
Other than the dwarf size, which is often seen in plants that grow in harsh coastal conditions, these weather-battered denizens adapt by developing thicker leaves and a denser habit. Additionally, this form is significantly more winter hardy than the typical material of Cyrtomium falcatum seen in the trade. We’ve always listed this dwarf form as a Zone 7a plant, but we wouldn’t be surprised at all if it’s also hardy in Zone 6. If you’ve been adventurous enough to try it, we’d love to hear from you. Our mature clumps below, photographed over Christmas, are now 8″ tall x 18″ wide.
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 – Dryopteris section 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.
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.
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.
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).
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
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.
The amazing Chinese native Pronephrium penangianum ‘Jurassic Park’ is looking fabulous in the garden this week. This large growing, spreading fern has the feeling of a plant from the time when dinosaurs roamed. We continue to make cool, but little-known ferns like this available to a wider audience. Hardiness is Zone 7b-9a at least.
One of our most amazing dwarf ferns is our 2008 Taiwanese spore collection of Microsorum brachylepis ‘Datun’. Our garden patch pictured below, which is looking great this month, was planted outdoors in 2017, and is now 4″ tall x 3′ wide. We offered this personal favorite a few years through Plant Delights, but the sales were rather miserable…what a shame. This delightful evergreen makes a superb, dense groundcover. Hardiness is Zone 7b-10b.
One of our favorite hardy garden ferns are the amazing cat’s claw ferns of the genus Onychium. The genus comprises between 9 and 23 species, depending on your choice of taxonomist.
The most common species in cultivation is the Japanese Cat’s claw fern, Onychium japonicum, which we’ve had the pleasure of offering many times through the year. Now, we’re working on getting another species into production, Onychium contiguum. Compared to Onychium japonicum, Onychium contiguum is much smaller and slower-growing with even finer cutleaf foliage. We picked up this Elizabeth Strangman wild collection during a 1994 trip to England’s former Washfield Nursery. Below is our original clump in the garden this week.
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.
Looking particularly lovely in the garden is the elegant fern, Dryopteris affinis ssp. affinis. The semi-evergreen golden-scaled male fern from Europe is among the easiest and most beautiful ferns we grow, yet when we offer it through the nursery, it’s always one of the worst sellers. We struggle to figure out mysteries like this when you have a fern that grows equally as well in acid or alkaline soils, and grows the same in the Pacific Northwest as it does the hot, humid Southeast US. Winter hardiness is Zone 4a-8b.
It’s not unusual for ferns to have sex in the wild, even with other species in the same genus. It is, however, unusual for them to have meaningful sex with ferns of an entirely different genus. Such an odd occurrence recently happened in the greenhouses of Louisiana’s James Georgusis.
One night, possibly after a wild Mardi Gras party, a willing Phlebodium got it on with a crested tongue fern of the genus Pyrrosia. The result was a new genus of fern, x Phlebosia. It was adopted and given the cultivar name, ‘Nicolas Diamond’. At least the parents had the good sense to sexually stay within the same family, Polypodiaceae
We planted our first specimens in the garden this February, and so far, it’s growing well. The key will be to see how much winter hardiness it has…fingers crossed. Both parents are pictured below the new hybrid.
Asparagus virgatus is undoubtedly one of our favorite textural perennials. How many evergreens do you know that thrive in shade with such an amazing texture, and can be cut for flower arrangements. If you’ve ever worked with cut flowers, you’ll recognize this as “filler” that you purchase with your flowers to add 3-D texture to your arrangements. Few people, however realize that it’s an easy-to-grow garden perennial.
Although in the wild, it grows along streams, it has proven to be one of the most drought tolerant plants we grow. In terms of light, an hour or two of morning sun is fine, but this South African asparagus species much prefers light shade all day. Unless winter temperatures drop below 10 degrees F, the amazing foliage stays evergreen. Hardiness is at least Zone 7b and warmer.
One of the most Jurrasic-looking plants we grow is the North American native Ostrich fern. If you moved here from “up north” and brought some of this fern with you, chances are it failed miserably. As a rule, Ostrich fern, Matteuccia struthiopteris, hates our summer temperatures.
Fortunately, back in the mid-1980s, retired UNC-Charlotte botany professor, Larry Mellichamp picked up a heat tolerant form from Powell’s Nursery in Princeton, NC, which he promptly introduced into the trade as Matteuccia ‘The King’. Without this incredible introduction, gardens in south would not have this amazing fern in their gardens.
This is a spreading fern that prefers average to wet soils, so allow plenty of room for it to spread. Below is a patch thriving at JLBG.
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.
Looking good in the garden this week is the amazing fern, Dryopteris x australis. This rare fern is a US native…despite the confusing name, hailing from only a few scattered locations from Virginia west to Arkansas. In reality, the name “australis” means from the south. This splendid specimen grows in both sun and shade, and tolerates both wet and dry soils. Hardiness is Zone 5a-9b.
Looking great in the JLBG gardens is the amazing Cyrtomium fortunei ‘China Ruffles’. This superb spore strain is from an original introduction by Michigan plantsman, Hans Hansen, who made the spore collection in 2003 in Sichuan, China. Hardiness is Zone 6-9.
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.
Just out in the garden in early January and wanted to share photos of a few of our favorite evergreen ferns that would rather not be growing in the ground. In our garden, these are all growing within a few feet of each other.
Each of these ferns are epiphytes, which grow attached to a tree, or lithophytes, which grow attached to a rock. None of these ferns actually need soil to grow, since they get their food and water from the atmosphere and accumulated organic debris. Epiphytes, however, don’t get nutrients from their host plant…only physical support.
All epiphytic ferns thrive in hanging baskets, especially the spaghnum-lined type, since this most closely mimics their natural preferences. In our case, we are a bit colder than their native haunts, so for us, we force these ferns to reside in the ground since that gives them a bit more protection during severe winter temperatures. The key for epiphytes to survive in the ground is to have very loose, organic soils and always plant them on a steep slope.
Neolepisorus fortunei ‘Green Ribbons’ is our 2017 introduction of a Chinese native epiphytic fern.
Pyrrosia lingua ‘Hiryu’ is also an epiphytic fern, native to Japan.
Lastly is Polypodium vulgare ‘Ulleung Island’. Instead of being an epiphyte, this evergreen fern is a lithophyte. Lithophytes are classified as either epilithic (growing across the rock surface) or endolithic (growing in cracks or crevices). Since we found this in the wild, growing across the surface of a giant rock, this fern is an epilithic lithophyte…say that three times fast. This is our 1997 collection from an island, far off the coast of South Korea.
We hope you’ll explore these unique ferns in your garden.
We always love it when unexpected garden hookups yield unexpected results, and such was the case recently when, under the cover of darkness, two of our holly ferns took a liking to each other. The result of this conjugal interlude is our first hybrid of Cyrtomium fortunei x Cyrtomium falcatum, that we’ve named Cyrtomium x fortatum Spornication. The habit of the hybrid is intermediate between both parents. Now, we’ve just got to figure out how to get it propagated in order to share.
We love the tardily deciduous Ctenitis subglandulosa ‘Hoshizaki’, which remains looking great in the garden as we pass the winter solstice. This truly elegant fern came to us from fern guru, Judith Jones, who got it from California fern guru, Barbara Jo Hoshizaki. The airy texture and ease of growth make this a fern we wouldn’t garden without. Sadly, we offered this Asian native (Bhutan through China) once through Plant Delights and very few people purchased one, so we had to discard the remaining crop…ouch! So very sorry you missed a true gem. Hardiness is Zone 7a-8b (guessing).
We love fall and winter, when Woodwardia orientalis ‘Mama Mia’ starts producing baby ferns on the old foliage. Mama Mia can be propagated from the plantlets, but in our cold winter climate, the babies rarely mature unless taken indoors for the winter. The evergreen foliage of Woodwardia orientalis will show damage at about 10 degrees F and Zone 7b is the northern-most range of its cold hardiness.
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.
Another genus of ferns that we just adore are the bamboo ferns of the genus coniogramme. We’ve grown these amazing gems for two decades, and after all that time are still in love. Although these woodland ferns are deciduous, they are tardily so, so they still look quite fresh into mid-November. Here are a couple of favorites, photographed this week.
At the top is the texturally fascinating Coniogramme intermedia ‘Shishi’ from Japan, and below this is our 2006 introduction of the Chinense native Coniogramme emeiensis ‘Golden Zebra’. We rate both of these as winter hardy from Zone 7b and warmer.
We love ferns of all types, but especially the single-leaf types. Our clump of the Chinese Lepisorus macrosphaerus really stands out in the fall and winter garden. In the wild, most lepisorus grow on rocks or tree trunks, but most we’ve grown have adapted well to growing in the soil. They tend to thrive better when growing on slopes, and in well-drained soils.
We’ve been growing the Chinese Arachnioides simulans, the similar spider fern, for over a decade, in which time, it’s proven a superb performer. Here’s a photo from the gardens this week. Finally, this spring, we got around to sowing spore, in the hope we can make this available soon though Plant Delights Nursery…fingers crossed for next year.