The genus Diplazium is quite large, containing around 400 species of ferns. Ferns in this genus are mostly tropical but we have found a few temperate species suitable as garden ferns in the South.
More Information About Diplazium
Diplazium is a group of ferns very similar to, and in fact once included in, the genus Athyrium. Most of us, of a “certain age” learned them as Athyrium (Lady Ferns) only to have their names change repeatedly. It is a large genus of about 400 species, the majority of which are tropical. The name Dipalzium comes from the Greek ‘diplazios’ which means double, because indusia lie on both sides of the vein; hence the common name for this group, the Twin Sorus Fern. One species, Diplazium esculenta, is widely consumed as a vegetable in Asia. The young fronds are eaten as a stir-fried vegetable or in salads in Phillipino, Malayan, Indonesian, Thai, and Indian cuisine. Interestingly, most, if not all, ferns contain toxic compounds, but they occur at low levels in this Diplazium. Strangely, one of the more toxic members, the ubiquitous Bracken Fern (Pteridium spp.), were consumed widely by native cultures in the Pacific Northwest but apparently always in moderation as these plants are well known for their toxicity as well as a chemical known as Ptaquiloside which has been shown to cause cancer in cattle and sheep.
The Best Diplazium Ferns for the South
Diplazium hachijoense ‘Barbara Joe’ (Barbara Joe Hachijo-jima Glade Fern) This is another little-known Asian fern (China, Japan, Korea) which can be found at elevations ranging from 1,500’ – 5,500’. It has proven extremely easy to grow in our climate in the woodland garden where it forms loose clumps of 3’ long, arching, evergreen, highly divided, triangular fronds from a creeping black rhizome. Not only is it an impressive and distinct looking fern but it’s also distinct genetically as it is an apogamous (self-gratifying) triploid. (Hardiness Zone 7b-9b, at least)
Diplazium maximum (Giant Asian Glade Fern) We obtained this fern from China around 2000 and have been thrilled with its performance in our woodland garden. In habit, it forms a 3’ tall x 4’ wide slowly spreading clump of broad, triangular, highly divided deep green fronds that resembles a small deciduous tree fern. We have grown many ferns, but nothing quite like this. Diplazium maximum prefers a slightly moist woodland soil for maximum growth. It has a large native range being found from Japan south to the Phillipines and west to Afghanistan. This species spreads very slowly and is a good substitute for the aggressively invasive Macrothelypteris torresiana and produces the same impact in the landscape. (Hardiness Zone 7b-10, at least)
Diplaziopsis pycnocarpa = Diplazium pycnocarpon (Glade Fern) Let us first say, this is a beautiful, native fern which produces upright, arching lime green pinnately compound fronds to 3’ long that resemble a Christmas Fern but are much more vibrant in color and deciduous. The fertile fronds stand erect in the center of the clump. It forms dense patches from rhizomes which expand slowly and will achieve a 3’-4’ wide clump in 5 years under good conditions. It is naturally found in moist, rich woodlands from Quebec and Minnesota south to Georgia and Louisiana, where it is always found in association with circumneutral soils that are derived from limestone, amphibolite or other rock that is high in calcium or magnesium.
Now let’s deal with the name applied to this plant. It was originally known as Athyrium pycnocarpon, then included in the genus Diplazium, then transferred to Homalasorus and now to Diplaziopsis! Wow (and a few other explicatives come to mind)! No matter what name you call it, this fabulous, easy-to-grow, deciduous clumping native fern should be included in every woodland garden. (Hardiness Zone 4a-9a)
Diplazium wichurae (Twinsorus Fern) Wichura’s Twinsorus Fern is among the most outstanding small evergreen ferns we have grown in the hot, humid climate of the Southeast. It makes a beautiful 4' wide patch in 5 years of upright, arching, dark glossy, plastic-like, evergreen 20" long fronds. Their dark, purple-tinted stipe and heavily veined leaflets make Diplazium wichurae one of the most distinctive looking ferns that we grow. It was named after the 19th century German plant explorer/botanist Ernst Max Wichura and is found growing naturally from Japan and Korea south through China and Taiwan. You will not find a better evergreen groundcover fern for the woodland garden. (Hardiness Zone 7a-8b at least)
Plant Delights Nursery has a huge collection of over 1000 garden ferns. We also have one of the largest and most esoteric selections of ferns for sale in the US. If you are looking to buy ferns, especially rare, cold-hardy, garden ferns, Plant Delights should be your first stop. Providing beauty and texture to the garden, ferns are great garden plants and are a staple of any well-designed garden.