Wards of the Woods

We have long been fans of the Asian ferns in the genus, Woodwardia. Of the eleven species in the genus, five are North American, and the rest are Asian. Our particular infatuation are with the giant, evergreen species, including Woodwardia prolifera, Woodwardia unigemmata, and the hybrid, Woodwardia x izuensis. All of these have huge, tropical looking fronds that can reach 3-7′ in length, and even longer in milder winter climates.

Woodwardia prolifera, formerly Woodwardia orientalis var. prolifera, is unique in that it also reproduces by forming large numbers of small plantlets on top of the foliage in early fall, prior to frost. Woodwardia prolifera was originally published as a unique species, but was later combined with Woodwardia orientalis, by herbarium taxonomists, who never bothered to actually grow live plants. More recently, it was once again realized to be quite different, so we’re now back to two different species. Because they were once lumped together, plants in the horticultural world, where taxonomy is often a second thought, are a mess. For years, all of the plants of Woodwardia orientalis we tried in our garden, died during the winter months. As we now know, this was probably true Woodwardia orientalis, which is a lowland, more tropical species, never occurring above 1,500′ elevation.

Years later, we finally acquired a winter hardy form of Woodwardia orientalis from the Hardy Fern Foundation at The Rhododendron Species Foundation, which survived fine, and also produced abundant plantlets on the leaves, leading to our decision to give it the cultivar name, Woodwardia ‘Mama Mia’. We now know that this plant is not Woodwardia orientalis, but instead is Woodwardia prolifera, which is much more winter hardy, since it occurs naturally to almost 4,000′ elevation. Below is a photo of that plant in the garden this week. For us, the developing young plantlets will die in a hard freeze if they aren’t removed before hand.

Another other species with equally huge foliage is Woodwardia unigemmata, which I first met in China in 1994. There, it typically hangs out on moist cliffs, near waterfalls creating large colonies.

Instead of producing plantlets on the top of the frond like Woodwardia prolifera, it produces only 1-2 plantlets per year, on the underside of each older frond. These plantlets look like a marble-sized ball of brown fuzz. These fuzzballs drop to the ground as the leaf ages, rooting into the soil, where another plant develops. The process continues as the fern creeps slowly outward year by year.

In Central Japan, where the two species co-habitate, an illicit evening rendevous occurred, resulting in the birth of a new natural hybrid, known as Woodwardia x izuensis. The hybrid, like the parent, Woodwardia unigemmata, forms plantlets on the underside of the leaf, but it produces more of them….usually four per year. This was published as a hybrid with Woodwardia orientalis, but based on its excellent winter hardiness, we’re betting that the other parent is actually Woodwardia prolifera, not W. orientalis. Our goal is to make all of these amazing ferns available for gardens from Zone 7b and south, where they should thrive.