There are four families of ferns having representative species that grow well in the Northeast. An additional family includes a fern that certainly grows in the Northeast, although perhaps not so well. The climbing fern (Lygodium palmatum) is an unusual vine-like fern that is found in several northeastern states, but it is variously listed as endangered, threatened or of special concern. It is included in the family Schizaeaceae and is hardy in U.S. Department of Agriculture plant hardiness zones 5b through 9a.
Polypod ferns are ferns in the family Polypodiaceae. Many, like the Christmas fern (Polystichum acrostichoides), USDA zones 3a through 9b, have leaflets that resemble stockings or the general outline of a foot. The name “polypod” essentially means “many feet.” Another fern in this family, the common polypody (Polypodium vulgare), USDA zones 5a through 8b, is a relatively small, rock-loving fern. In some ways the common polypody resembles a downsized Christmas fern. Both of these ferns are evergreen, while others in the family die back in the winter.
The succulent ferns -- or “adder’s tongues” as the common name interpretation of the scientific family name, Ophioglossaceae, reads -- include the rattlesnake fern (Botrychium virginianum), USDA zones 4a through 9b, and the cut-leaved grape fern (Botrychium dissectum), USDA zones 3a through 9b. The rattlesnake fern is a medium-sized fern that grows well in sites with rich, moist soil and shade. The cut-leaved grape fern is a relatively small fern and tolerates a wide range of site conditions.
The water shamrock (Marsilea quadrifolia) is an aquatic fern that has become established in the Northeast. It is native to Europe but grows well in the United States. In fact, it grows so well that it has become invasive and is banned from sale and distribution in at least two New England states. As its name indicates, the water shamrock leaves are divided into four parts that suggest a shamrock or clover. This fern is in the family Marsileaceae and is hardy in USDA zones 6a through 8b.
The common name “flowering ferns” for the family Osmundaceae is a misnomer, since ferns are really not flowering plants. Ferns in this family do, however, produce their spore-bearing parts on stalks in such a way that they can resemble a flowering structure that is either developing or that has gone by. The royal fern (Osmunda regalis) and the cinnamon fern (Osmunda cinnamomea) are two representatives of this family that grow well in the Northeast. Both are hardy in USDA zones 3a through 10b.
- A Field Guide to the Ferns; Boughton Cobb
- New England Wildflower Society: True Ferns and Moonworts
- Dave’s Garden: Cinnamon Fern
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