Whether indoors or outdoors, ferns add life to your landscape.

April 18, 2011

Ferns are the quintessential shade plants. Their graceful, arching fronds conjure up images of shaded retreats and cool walks by wooded streams. Ferns will grow in the deepest, darkest woodland. They will grow in moist soil and even standing water. However, not all ferns are limited to the shade. Marsh fern, cinnamon fern, and bracken fern grow in full sun. But most ferns prefer moist soil and partial shade.

Ferns In The Landscape
Use large ferns as foundation plantings along with or instead of shrubs. Plant them along fences or walls to break up the flat expanse. They hide the "bare ankles" of sparse shrubs or perennials. Large hostas and ferns will add interest to a shaded spot. Mass plantings of ostrich ferns (Matteuccia spp.) and osmundas (Osmunda spp.) are very effective for filling bare spaces or adding depth in the shade of tall trees. They also form a perfect backdrop for annuals and perennials. 
Use medium-sized ferns such as New York fern (Thelypteris noveboracensis), lady fern (Athyrium filix-femina), and maidenhair fern (Adiantum pedatum) in combination with spring wildflowers. Their unfurling fronds are a beautiful complement to spring beauty (Claytonia virginica), wild blue phlox (Phlox divaricata), and others. Fronds will fill in the blank spots left when wildflowers and spring bulbs go dormant. 
Try ferns along the border of a shaded walk to define the path, or ferns with creeping rhizomes on a slope to hold the soil. Mix textures and add evergreen ferns such as wood ferns (Dryopteris spp.) and Christmas ferns (Polystichum acrostichoides) for late-season and winter interest. 
Crown-forming ferns like interrupted fern (Osmunda claytoniana) and cinnamon fern (O. cinnamomea) have a graceful vase shape and make excellent accents alone or in small groupings. They grow slowly, so they won't take over the garden like some running ferns such as hay-scented ferns (Dennstaedtia punctilobula). Plant rampant growers where they can spread to form groundcovers and fill in under shrubs. For low, wet areas, chain ferns (Woodwardia spp.), osmundas, and marsh ferns (Thelypteris palustris) are stunning. Combine them with the spiky foliage of yellow flags (Iris pseudacorus) and arrowheads (Sagittaria spp.). 
Since foliage is the fern's major attraction, consider the color and texture of the fronds. The most colorful garden fern is the Japanese lady fern, Athyrium niponicum. Its hybrids and cultivars, including the many cultivars of A. n. 'Pictum', Japanese painted fern, may have fronds that are gray, blue-gray, gray-green, gray-white, or seemingly variegated with colorful burgundy midribs. (In fact, Athyrium niponicum 'Pictum' was considered so outstanding that it was named Perennial Plant of the Year for 2004 by the Perennial Plant Association.) All of these but the gray-green cultivars look great with blue hostas and heucheras with garnet or purple foliage or gray leaves with garnet veining (Heuchera 'Palace Purple' is a well-known purple-leaved cultivar). The explosion in heuchera breeding has also produced cultivars with gray-green foliage, some with garnet veining, that combine beautifully with the gray-green cultivars of Japanese painted fern; add green or green and white hostas for textural contrast. 
Japanese lady and painted ferns aren't the only ones that offer color and shine to the shade garden. Chartreuse-colored interrupted fern and maidenhair fern combine well with dark ferns and other foliage. The coppery new fronds of autumn fern (Dryopteris erythrosora) and its orange-red cultivar 'Brilliance' add warmth to shady sites and look lovely with chartreuse-leaved hostas, heucheras, and tiarellas, as well as heuchera cultivars with coppery foliage. The shiny fronds of ferns such as autumn fern, deer fern (Blechnum spicant), and hart's-tongue fern (Phyllitis scolopendrium) glisten in filtered sunlight. 


Preparing The Soil
Ferns generally require rich, moist soil with extra organic matter. Some require a drier, less-fertile soil. If ferns haven't done well for you in the past, have your soil tested by your local extension service or a soil-testing lab to determine soil fertility and pH. Some ferns are extremely fussy about pH.
For large and medium-sized ferns, dig the planting area deeply (at the very least, turn the soil to a spade's depth). Plant smaller ferns such as Japanese painted fern as you would any perennial. Sprinkle on organic fertilizer, if needed, when you add soil amendments. For more on organic fertilizers, see the Fertilizers entry.
Buying And Planting Ferns
Garden centers offer a few ferns, but you can find more through nursery catalogs and Web sites that specialize in perennials, shade plants, or ferns. No matter where you buy, make sure plants are nursery propagated, not collected from the wild. Large plants at low prices usually mean wild-collected plants. Don't be afraid to ask for the vendor's sources.
Plant ferns in fall or early spring. Garden-center plants will be potted, but mail-order plants are likely to arrive bareroot. Remove potted plants from their containers, cutting the plastic if necessary. Very carefully score the root ball with a sharp knife. Make 3 to 5 shallow cuts lengthwise down the root ball. This breaks up the solid mass of fibrous roots that often forms along the container wall. Plant the fern at the same level at which it was growing in the pot. Planting too deeply will kill plants with single crowns. 
Set bareroot plants with creeping rhizomes (underground stems that produce both roots and fronds) 1/2 to 1 inch below the surface. Large rhizomes can be planted deeper. Set single-crowned ferns like osmundas and ostrich ferns with the crown above soil level. Place the upper part of the rhizome above the soil surface, with the crown 3 to 5 inches above the soil, depending on the plant's size. Finally, don't plant too thickly, since most ferns spread rapidly.
Continuing Care
Ferns are a carefree group of plants. Mulch with shredded leaves or bark to help control weeds and conserve moisture. Ferns never need staking, pinching, or pruning. You may have to remove an occasional damaged frond, but that--and watering during dry periods while the plants are getting established--about sums up the care requirements for ferns during the growing season.
Each spring, remove last fall's leaves from the fern bed, shred them, and return them to the bed. Clear the bed early to avoid damage to emerging fiddleheads. Don't rake the beds, or you may damage crowns and growing tips. You won't need fertilizer if you leave the mulch to rot into the soil.