Christmas fern (Polystichum acrostichoides) is not the most dazzling plant. It doesn’t flower or fruit or turn bright colors in autumn. Yet it’s a utility player well worth having in your horticultural lineup. Its glossy, emerald green fronds and fountain-like shape bring a coolness to the garden and act as a foil for flashier plants. This fern is very easy to grow, a reliable, long-lived performer and a good solution for problem spots such as full shade, poor soil, or erosion.
Called Christmas fern because its fronds stay green through December, the lustrous fronds are often cut and used in seasonal holiday decorations and as accents in floral arrangements. Other common names for the plant are dagger fern, Christmas dagger fern, and sword fern.
In many areas of the U.S. it’s one of the few spots of green in an otherwise brown and gray landscape, making it a good choice for winter interest in the garden. Each frond lives for a year and is replaced in the spring, so it’s not exactly “evergreen” as much as “wintergreen.” In spring, the emerging fiddleheads are silver.
Christmas fern is native to Eastern North America, but is found in all 48 contiguous United States. In the wild it’s mostly found in cool woodland areas. Deer and rabbits don’t eat it and it is tolerant of black walnut. The ASPCA states that Christmas fern is not toxic to dogs, cats, or horses. It’s not toxic to humans, either, but it’s not considered edible.
Photo by and (c)2007 Derek Ramsey (Ram-Man), CC BY-SA 2.5 <https://creativecommons.org/licenses/by-sa/2.5>, via Wikimedia Commons
Zones: 3 to 9
Height: 1-2 feet
Spread: 1-2 feet
Light: Part to full shade. The plant can tolerate dappled sunlight but not full sun; its fronds will bleach and growth will be stunted.
Soil: Being a woodland plant, this fern prefers moist soil rich in organic matter with a pH of 6.8 or lower. It does surprisingly well in poor, even rocky soil, but not clay.
Water: Christmas fern tolerates dry soil and drought. Wet soil or too much water can cause the crown of the plant to rot, especially in wintertime.
Care: Mulch plants with 2” of shredded leaves, leaf compost or shredded bark. No need to fertilize. Cut off the old fronds when you see new fiddleheads emerge. Divide in early spring.
Christmas fern is a natural for a shade or woodland garden or any partly shaded place you want ground-level color in winter. It makes a good foundation plant for the north side of a house. Its root system is fibrous, so it’s also a great choice for shady slopes, stream banks, hillsides or any place prone to erosion. Planted en masse, the ferns have a rather primeval look, as if a brontosaurus might appear any minute to munch on the leaves.
Photo by David J. Stang, CC BY-SA 4.0 <https://creativecommons.org/licenses/by-sa/4.0>, via Wikimedia Commons
Although it grows by rhizomes, the plant stays in a clump. An existing clump will grow bigger but it won’t naturalize or spread, so unlike many rhizomatous plants, it’s not exactly a groundcover in that it doesn’t become a solid carpet of green.
This fern makes a nice backdrop to spring blooming bulbs. Pair with ephemerals such as bleeding heart (Dicentra), Virginia bluebells (Mertensia virginica), and viola, and perennials such as forget-me-not (Brunnera), woodland phlox (Phlox divaricata), hosta, and lungwort (Pulmonaria).
Christmas fern reproduces by spores. It doesn’t fruit or go to seed, which means it’s not an essential plant for wildlife. Most insects, birds and animals don’t like the taste of the fronds, though it provides protective cover, especially for ground-nesting birds such as wild turkeys. Songbirds also use parts of the plant in nest building.
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