Now that we’ve had several hard frosts, many of the herbaceous wild plants have withered. There is one native woodland fern that is still bright and green. It’s called Christmas fern (Polystichum acrostichoides) and it’s a native with untapped potential.
In wilderness areas I’ve seen it grow in soils that are commonly flooded. I’ve also found it on steep rocky sites. Usually, Christmas fern is found in places somewhat in between these extremes, but it’s an adaptive pterophyte.
Soil pH is not critical, but plant growth is more vigorous at near neutral pH ranges. That’s probably why it’s common on limestone influenced soils. It grows best in shade, but it tolerates significant sun too.
Christmas fern is common all over the eastern US. It even can be found as far west as Texas. It’s probably more prolific in northern areas, but it is still abundant here. The plant gets its name because its foliage is usually still green at Christmas, even in northern areas.
Plants achieve heights up to two feet, but generally they are somewhat shorter. Individual leaves (fronds) are leathery and glossy. They have many leaflets and can be three feet long. Some of the fronds have a spreading or cascading growth habit, while others are more upright.
These upright fronds are often the fertile ones. Leaf backsides have clusters of spores on the upper third to half of the leaflets. These fertile leaflets near the frond tips are shorter than the sterile ones at the frond bases.
Plants have an extensive underground rhizome system, but they generally don’t take over an area. One would expect them to form dense mats, but they usually form small mounds instead. I’ve never heard of their becoming invasive.
I’ve seldom seen them planted as ornamentals, but I’ve dug them from the wild and they transplant well. The best time to gather them is in spring before weather gets too warm.
Some nurseries are beginning to grow Christmas fern for sale, so I expect it might get more popular in the future. It’s a low maintenance plant, and that’s a selling point too.
Once established these hardy ferns have inconsequential enemies. Few insects bother them, and they’re not prone to disease problems. Best of all, deer don’t like to eat Christmas fern. Dogs and other pets generally leave it alone too. It’s not listed as poisonous to them either.
I don’t recommend this one for human consumption either. It probably won’t hurt you if you cook it, but plants contain an enzyme called thiaminase that robs the body of B vitamins, particularly Vitamin B1. Cooking denatures the enzyme rendering it harmless.
Tea from Christmas fern leaves has been used by native Americans in the past to treat digestive issues and joint problems among other things. It’s used very little today.
While culinary and medical uses are limited, leaves of this fern are useful in floral designs. Shiny leaflets and showy spore clusters add character to an arrangement. They hold up well too and can be dried for year-round use.
Ted Manzer teaches agriculture at Northeastern High School.