University of Vermont Extension 
Department of Plant and Soil Science

Summer News Article
line
NATIVE FERNS
 
Dr. Leonard Perry, Extension Professor
University of Vermont
 
Northern New England's native ferns are spectacular, both in the wild and in cultivation. The variety of size, form, and texture is remarkable, and the various habitats where these ferns thrive are somewhat surprising.
These dozen described here are among the most popular and best for gardens, are easy to grow, and are hardy to at least USDA zone 4 (-20 to -30 degrees F average winter temperature).  You can find many at garden centers that have a wide selection of perennials, although you may have to contact a specialty nursery to find others.
           
Northern maidenhair fern (Adiantum pedatum), up to 18 inches tall, is the daintiest of the native ferns. Its black stems are topped with a fan-like arrangement of “pinnae” (leaf-like segments or leaflets, arranged along either side of a central stalk or “rachis”). It does best in filtered light and well-drained, cool soil. This fern spreads fairly slowly. 
           
The ebony spleenwort (Asplenium platyneuron) reaches a foot or slightly higher in moist but well-drained soils, and part shade (4 to 6 hours of direct sun a day) to shade.  The pinnae on this fern look like shark’s teeth, and are in two rows on either side of dark stems which give a very flat appearance to the “fronds” (fern leaves). Fertile upright fronds (those with minute fern reproductive units called “spores”) come out in spring, followed by smaller and more curving sterile fronds in early summer. 
           
Lady fern (Athyrium filix-femina) is quite variable reaching 18 to 36 inches in height.  Its leaves have the quintessential “fern” look, with roughly triangular fronds, “bipinnate” (twice divided).  There are quite a few cultivars (cultivated varieties), many popular and first introduced during the Victorian era, with various shaped pinnae.  Lady fern produces a vigorous flush of reddish-green growth in the spring when it is at its most spectacular.  
           
In 2000, the New England Wildflower Society introduced the popular cultivar ‘Lady in Red’ lady fern with deep red leaf stalks.  This actually was found in the wild in Vermont by one of this society’s members.  Lady fern grows best in shady conditions with moist to wet soil, but will tolerate a half-day of sun if sufficient moisture. 
           
Hay-scented fern (Dennstaedtia punctilobula) reaches 2 feet in height and spreads fairly rapidly up to 3 to 4 feet wide.  You can easily control the spread by pulling out some of the growth in spring, but don’t plant it near weakly-growing plants or they’ll be overrun.  An advantage is that it will out compete many weeds.  This fern grows best in full sun to partial shade and tolerates rather hot, dry sites once established, as well as acidic soils. Hay-scented fern produces apple-green, lacy (bipinnate) fronds that lend a delicate texture to the garden. When you bruise or crush the fronds they release the odor of new-mown hay.
           
While some of the wood ferns are moderately difficult to grow, some such as the popular male fern (Dryopteris filix-mas) are easy.  Although a clumping fern, it makes colonies up to 3 feet across in 5 to 10 years.  Plants are 2 to 3 feet high, with flattened two-dimensional fronds which turn golden to burgundy shades in fall.  The male fern grows best in shade and moist soils. The related marginal wood fern (Dryopteris marginalis) is drought tolerant once established.
           
Ostrich fern (Matteuccia struthiopteris var. pensylvanica) is a three-foot fern that produces gracefully arching fronds.  Long-tapering at the base, and short-tapering at the tips, the sterile fronds resemble ostrich plumes in shape. The stiff fertile fronds arise in the middle of each clump in summer, reach two feet in height, and persist into the winter. The early spring growth (“crosiers”) resemble fiddleheads, hence the name, and are edible as many in New England know. Ostrich fern grows best in sun to partial shade and moist soil. Be careful where this is planted, as it will spread to form dense colonies many feet wide, shading out less vigorous yet desirable perennials.
           
Cinnamon fern (Osmunda cinnamomea), along with the other members of this genus, is named after Osmunder, Saxon god of war. The Osmunda ferns are among the most vigorous of all garden ferns and are not for small sites.  The stiff fertile fronds of the cinnamon fern appear in spring, first green and later turning cinnamon-brown, making them easy to identify. Next, the handsome fiddleheads unfurl into three-foot arching sterile fronds, which have cinnamon-colored fibers along their base. In fall, these fronds turn golden. This fern does best in a shady site with moist soil, and is commonly seen in wetlands of eastern North America.
           
Interrupted fern (Osmunda claytoniana) is unusual for its sterile, three-foot tall fronds that have brown spore cases in the middle with green pinnae both above and below, thus being “interrupted”.  Interrupted fern performs best in a shady site with moist soil, but it tolerates higher light and drier soil than most ferns. This is one of our oldest plants, with virtually the identical fern being found in fossils from the late Triassic period 220 million years ago.
           
Royal fern (Osmunda regalis var. spectabilis) forms a three-foot, vase-shaped clump. The wiry roots (“rhizomes”) resembling a scouring pad were once aggressively harvested and used as a growing medium for orchids. The plant's smooth fiddleheads develop into bright green, broadly triangular fronds with large smooth pinnae. Light brown spore cases develop on top of the fertile fronds, giving rise to another common name, "flowering fern." Royal fern tolerates shade, but grows best in sun and wet soils.
           
The New York fern (Parathelypteris noveboracensis) is one of several ferns that have been placed by botanists into a new genus, and is the most available and easy marsh fern.  It is a good choice for a smaller fern that will cover some ground fairly quickly, yet not overrun other plants. Growing two feet high, it forms colonies more readily in wet soils yet tolerates drier soils.  Leaves are rather narrow—3 to 5 inches wide—and tapering at both ends.
           
Christmas fern (Polystichum acrostichoides) is one of the few evergreen ferns of Northern New England, easily seen during the late fall in deciduous woodlands. The leathery fronds reach a foot or more high, with a similar plant spread. This is a durable and unfussy fern that is not overly aggressive and is easy to incorporate into most shade gardens, making it one of the top ferns for those in eastern states. It is quite adaptable to climates and soils, growing wild from Maine to Florida.  Its fronds were once popularly used for Christmas decorating.  If cutting some for this purpose, just take a few from each plant so not to weaken the clump.
           
More details on these ferns, plus many more ferns as well as mosses and grasses, can be found in the excellent and easy-to-read reference by William Cullina, Native Ferns, Mosses and Grasses.

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