Cyrtomium is a small genus of 15 to 20 fast growing terrestrial or rock-inhabiting evergreen fern species from around the world. In the Pacific Northwest they are reliably evergreen and are a wonderful, easy to grow addition to any woodland garden or shade container. The common name "Holly Fern" derives from the shape of the frond which is similar to Holly and Oregon Grape. Of special note is the unique dark green and glossy look to the fronds that makes them a stand-out addition to the shade garden. Fronds generally range in length from 1 to 2 1/2 feet in length.
Cyrtomium make great companion plants for larger Hostas and other bold-leaved perennials when planted in the ground. The texture of the serrated edges of Cyrtomium contrast well with soft textured perennials such as Farfugium, Podophyllum, Tiarella, Rodgersia and Brunnera. In addition, they also pair well with shrubs such as Rhododendrons and Hydrangeas.
Planted in shade containers, Cyrtomium work well with Pansies, Primroses, Hellebores, Cyclamen and smaller-leaved Hostas. Also, because they are evergreen, Cyrtomium add great texture to pots year round, especially in winter when perennial options are more limited.
Cyrtomium prefer moist conditions as they are largely native to damp forests or banks of rivers. Thus, some supplemental water during the driest parts of summer may be necessary. Their range of cold hardiness is from USDA zones 6 to 10.
Also, Cyrtomium appreciate acidic, nutrient rich soil with good drainage. Thus, an addition to the soil of compost and pumice at planting time is beneficial. Baiting for slugs with Sluggo or another slug control product will also help to keep ferns looking nice. In terms of propagation, Cyrtomium may spread in the garden via spores or they can be propagated by dividing the fern's rhizome in autumn or early spring.
Japanese Holly Fern
This species is native to Japan and has a beautiful and distinctive shape with its few fronds forming a vaselike crown. Fronds are four to seven inches wide and are produced in rosettes on slender stalks emerging directly from the rhizome. The fronds are very dark green and glossy like holly.
Cyrtomium f. Rochfordianum
Rockford Holly Fern has glossy leaflets that are dark green with coarsely toothed margins. This is a vigorous variety.
Fortune's Holly Fern
This species is native to southern Japan, Korea and China. It is hardier than Cyrtomium falcatum. It is distinguished from C. falcatum by its greater number of fronds which are paler green, duller and with fewer teeth on the margin. This fern also has noticeably dark purple stems, thus contrasting nicely with yellow Hostas.
Large-leaved Japanese Holly Fern
Similar to Cyrtomium fortunei but with fewer and larger, broader leaflets that are not as distinctively purplish. Fronds are more yellowish green in color. This species is great in the garden and can also be potted-up and brought inside as an attractive houseplant.
Common Name: Holly Fern
Origin: Hawaii, East Asia to South Africa and Central to South America.
Culture: Loose, nutrient rich, woodland soil with rocks or pumice to insure good drainage. Cyrtomium prefer abundant water in summer, less in winter. They tolerate drier air than most ferns and grow best in medium to high light. Keep them out of direct sunlight in summer.
Maintenance: Cyrtomium are evergreen and require minimal cleanup in early spring before new fronds emerge. Prune back damaged and old looking fronds to leave room for the newly emerging fronds.
Pests and Diseases: Slugs and snails are a potential threat to holly ferns, as is root rot due to poorly draining soil. Sluggo is a kid and pet friendly way to control slugs, and choosing an appropriate planting site is the best defense against root rot.