How to Grow Christmas Ferns

Ferns can be versatile additions to a shady spot in a home garden, bringing a woodland character to any planting. The Christmas fern (Polystichum arcrostichoides) is a good example that gets its name from its ability to remain bright green at holiday time. It grows in U.S. Department of Agriculture plant hardiness zones 3 through 9 and thrives when given good growing conditions and just a bit of extra care.

A Christmas fern grows best in partial to full shade; too much sun can scorch its dark green leaves and interfere with its growth. When planting, choose a spot that gets no strong sun during the day to avoid scorching of the fern's fronds.

The plant needs fertile soil that's well-drained, to promote strong growth and help combat fungus, which can grow in soil that stays soggy for long periods. To increase your soil's fertility, mix in 2 or 3 inches of compost at planting time. If your soil contains clay and tends to drain slowly, also add some coarse sand to help improve its drainage.

A Christmas fern is about 2 feet tall and wide when mature, so allow about 2 feet of free space in all directions to let the plant spread fully without crowding. Christmas ferns have fleshy, horizontal roots called rhizomes. When planting, place each rhizome at a slight angle in the planting hole, so that the foliage-producing end is a bit higher than the other end and the growing tip shows slightly above the soil line. This improves drainage and helps prevent a fungal disorders.

The Christmas fern is adaptable to most moisture levels and can tolerate periods of dryness once established. During its first year it appreciates regular watering and even moisture, which gives the plant a good start and helps build strong roots. Give the plant supplemental water whenever the top of its soil feels dry to the touch, but water at ground level under the canopy with a soaker hose or drip irrigation, and don't allow water to accumulate at its base or crown.

Fertilizing when you see young fronds appearing in spring helps a Christmas fern start the season with strong new growth. Like most ferns, it's easily burned by strong fertilizer, so use a slow-release, granular, balanced formula, such as 14-14-14, at an application rate of about 2 ounces per 10 square feet of area under the fern, but check your product label for additional directions. Water the fertilizer in well after application.

Fronds on a Christmas fern stay healthy and green during winter, although they might lie flat on the ground during cold weather. To keep the plant looking tidy, use sharp shears to cut back old, unattractive fronds each spring when you see the start of new growth, but wipe blades with rubbing alcohol between each cut to discourage spread of plant disease.

The Christmas fern is usually a pest- and disease-free plant when grown under correct conditions.

In moist soil, the plant might attract slugs, which are unsightly and can feed on foliage, although they rarely do significant damage. You can control these pests by hand-picking them, or place a saucer or other shallow dish filled with sweetened water under the canopy to trap them.

The plant can also develop fungal disorders that include crown rot, but planting in well-drained soil and keeping water from pooling in the fern's center helps avoid this problem.