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.
Below is another clump nearby, that emerges about a week earlier, and as such, is further along in opening.
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.
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.