Regional Plant Specialist: Ferns

Cyrtomium falcatum

One of the simple pleasures in life is visiting preserved woodlands and forests where towering trees create shady, often damp environments. Not many plants can grow in the low light levels cast by groves of large trees. Mosses often cover the ground, and of course, the signature plant of many forests -- the fern.

Ferns are survivors, living where few other plants do well. And they have been doing it for a long time, as evidenced by the abundance of fossilized specimens of ferns.

In a landscape setting, ferns make striking accents in the shady garden. While many plants are grown for their flowers, ferns are noted for their finely textured leaves and pleasing green color. Some fern varieties have fronds that are a light green, some dark green, and others with surprising colors of grey, silver, red and blue-green.

Ferns serve a great role in the landscape because they grow so well in both partial and fully shaded settings where plant selection is limited. A morning sun exposure would be better than afternoon sun, which can burn the fronds of many types.

Another plus of ferns is that they grow well in damp, even wet, soils where few other plants will grow. However, many ferns are sensitive to poor water quality, especially salts.

Most ferns require a rich, well-drained, moist soil with lots of organic matter. Yearly mulching with leaf mold will encourage a thriving colony of ferns.

Ferns do not produce flowers, but reproduce from spores that form on the undersides of their fronds. These spore-bearing structures are often mistaken for scales or some other insects. Some ferns produce two types of fronds. One is a sterile frond with the characteristic fern-shape, and the other often appearing as a stalk with tiny beads packed together bearing the reproductive spores.

Ferns spread by underground rhizomes, some more aggressively than others. Spreading types are easily propagated by division in early spring just as the new growth begins to show. Take care not to plant the aggressive spreaders where their rampant growth would be a problem. Those types are better suited for woodland settings, along streams or other areas where their spreading nature is welcome. Others grow much more slowly, often referred to as clump-forming.

Some companion plants for ferns include aspidistra, columbine, liriope, caladiums, ligularia (Farfugium), Fatsia, aucuba, hosta, ajuga and hydrangeas.
 

A sampling of shade lovers
Adiantium capillus-veneris (Southern maidenhair fern) - A graceful, delicate-looking, yet tough fern that grows well in a wide range of conditions. It's a spreading, deciduous fern.

From top to bottom: Polystichum polyblepharum. Athyrium filix-femina. Athyrium niponicum ‘Pictum’. Dryopteris erythrosora. Onoclea sensibilis.

Polystichum polyblepharum (tassel fern) – A very handsome and attractive, evergreen fern with hairy, dark-green fronds. It does not spread, but the fronds grow larger each succeeding year. It tolerates low-light conditions.

Athyrium filix-femina (lady fern) - This fern looks delicate but makes a strong presence in the garden. It has finely cut fronds, and the overall form is vertical, growing about 2 to 3 feet tall. Some references indicate it can be invasive, but I've grown it for several years, and it is not as invasive like other ferns I've grown.

Athyrium niponicum 'Pictum' (Japanese painted fern) - This popular plant (the 2004 Perennial Plant of the Year) is readily available, and it is no wonder. It is hardy and very pretty, sporting multicolored fronds with silvery grey fronds and hints of purple and red. It spreads slowly and doesn't get very tall (up to 2 feet). It prefers evenly moist soil.

Cyrtomium falcatum (holly fern) - This is another popular fern, with bold, long, large, dark green, evergreen fronds. It needs some protection in a severe freeze. Remove winter-damaged fronds to keep tidy. It does well in low-light areas. This fern is not a spreader, so plant about 2 feet apart.

Dryopteris nomalis (also Thelypteris nomalis , and T. kunthii in some references) (Southern wood fern, Southern river fern) - This is one of the most common landscape ferns of the South. Long, arching, light-green fronds light up dark areas with a soft texture. It spreads quickly by rhizomes, rapidly filling in an area.

Dryopteris erythrosora (autumn fern) - This is another popular semi-evergreen fern with arching fronds of a fine texture. The fronds in spring take on a coppery-pink hue, turning green in summer and a rusty copper in fall. Remove damaged foliage in spring just as new growth emerges. It reportedly takes some drought.

Onoclea sensibilis (sensitive or bead fern) - This fern gets one of its names because the light green fronds, which turn yellow to russet in the fall, are easily burned by frost. Bead fern refers to the fertile fronds which, instead bearing leaflets, have compact clusters of beadlike sori that persist through the winter, providing landscape interest and good material for dried flower arrangements. It grows rapidly and must be controlled in smaller beds, but it's a good choice for the right spot in the landscape with moist soil.

Osmunda regalis (royal fern) - This is a large, distinctive fern with twice cut fronds bearing large leaflets. It produces a distinctive cluster of beadlike sori at the tips of some of its fronds. This fern requires acidic, consistently moist soils.

Polystichum acrostichoides (Christmas fern) - A southeastern native, evergreen fern that looks similar to a Boston fern with stiff, upright leaves. It grows slowly, preferring shade and well-drained soil.

Keith C. Hansen, is county extension agent, Texas AgriLife Extension Service, Smith County; khansen@ag.tamu.edu.