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Ferns For The Shade Garden - Part III

© Marge Talt

For those of you who have not read my previous articles on ferns, the mini-glossary of fern terms is located at the end of this article.

Here are some more ferns that I grow in my USDA zone 7 garden:

MORE HARDY FERNS

Osmunda regalis (Royal or Flowering Fern)

Royal Fern is an extraordinary fern. The sterile fronds resemble Black Locust (Robinia pseudoacacia) leaves more than they do most ferns, and the fertile fronds, which emerge in the center of the clump, look a great deal like spent Astilbe flower heads once they are mature. The unfolding fiddleheads have curious woolly caps that detach as the unfurling progresses. I think the variety I have is O. r. var. spectabilis, which, unlike the first photograph (probably an old-world variety), has a more willowy habit with slenderer pinnules on pinnae spaced farther apart. Pinnules are the ultimate division of a pinnae, the primary division of a blade -- think of a divided leaf.

In very early spring, the croziers unfold, tall and rigid; by midsummer the fronds arch out like a fountain, so give this one a lot of room. Royal ferns can reach six feet (182 cm) tall and a clump can form a circle as big around.

This is a deciduous clump former with woody rhizomes that overlap and interlace, forming a thick, spongy-looking mass above ground. It's this rhizome mass that provides the Osmunda fiber so much used for potting orchids. If you want to divide one, you need to wait until the fiddleheads start to emerge so that you can see where they are going to come up -- it's never in the same place as the previous year's lot.

Royal ferns are native from Canada to Florida and Missouri and rated hardy to USDA zone 2. They require a highly acid soil and really need a lot of moisture. They should be planted in part shade unless in quite damp conditions, when they can take more sun.

A bit of research indicates that there are several variations.

• O. r. cristata (Crested Royal Fern) is also deciduous, reaching a height of three to four feet (91 - 121 cm) but capable of making a clump many feet in diameter;
• O. r. gracilis has bronze-colored fronds;
• O. r. var. palustris has fronds only about three feet (91 cm) long that are reddish;
• O.r. 'Purpurascens' (Purple-stem Royal Fern) is most likely, according to one of my fern catalogs, a variation of the old-world type due to its robust nature. Its fronds unfurl with a mauvey-coppery cast and the rachis (mid-rib of the blade) and stipe (leaf stalk) remains a vibrant claret while the frond matures pea-green. This is one I've got on my wish list.

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