The Christmas fern (Polystichum acrostichoides) isn't just an ideal evergreen for adding color during the festive season. The clusters of lush, dark green fronds will shine year-round with little maintenance if it gets the right cool, moist, shady conditions.
New tightly coiled silvery-green fronds unfurl in early spring, growing in rhizome-spreading clumps that work well in borders or as accent plants. They pair well with perennial wildflowers and other shade-loving ferns and aren't fussy about soil types, making them ideal for woodland or cottage gardens. They also suit being planted en-masse on slopes to help with soil erosion.
Although they stay green in winter, the fronds lose their upright, arching shape and lie flat on the ground. But, providing they aren't covered in snow, they provide good shelter for the birds visiting your garden, and they're fans of the fronds for nest construction.
If you don't want to attract Bambi to your backyard, Christmas ferns are a relatively deer-resistant plant option. Although, it's worth noting that herds have been observed grazing on them when there's no preferred food source around.
|Common Name||Christmas fern|
|Botanical Name||Polystichum acrostichoides|
|Mature Size||Up to 2 ft. tall|
|Sun Exposure||Partial, Shade|
|Soil Type||Moist, Well-drained|
|Soil pH||Acidic, Neutral|
|Hardiness Zones||3-9 (USDA)|
|Native Area||North America|
Christmas Fern Care
Christmas ferns are low-maintenance, long-lived plants that are ideal for novice gardeners—as long as you can offer them the shady conditions they thrive in. Compared with other native ferns, they're adaptable, not bothered by serious pests or diseases, and have a surprising amount of drought tolerance.
Introduce new plants in the spring, after the danger of any frost has passed. Planting them around 18 inches apart offers up the space this clumping species needs. Adding a leaf mulch around the base helps to retain moisture.
As with many fern species, these plants thrive in conditions resembling the shady, moist floor of their natural forest habitat. They can tolerate full shade but prefer a dappled, part shade position. Although they can handle more brightness than some fern species (providing they have adequate moisture), watch out for exposing them to too much sun. This can stress your Christmas fern out and result in the fronds losing their lush green shade and looking washed out, stunting growth.
Christmas ferns are pretty forgiving regarding soil conditions, providing it's well-drained. The only soil type they aren't keen on is dense clay, as they're prone to crown rot if left in standing water, particularly in the winter. They'll perform best if the soil is rich in organic matter and moist, but they can tolerate dry, infertile conditions. Mulching around the plant boosts nutrients and helps to hold in moisture.
Getting the moisture levels right can be the key to flourishing ferns. A once-a-week watering schedule during the growing season is usually more than enough to maintain even moisture. You don't want to let the soil get waterlogged, and while they're mildly drought-tolerant, allowing them to dry out too much won't encourage the healthiest-looking plants.
Temperature and Humidity
Don't attempt to grow Christmas ferns in hot and dry regions. These frost-tolerant plants like cool, shady spots. Temperatures of around 50 to 70 degrees Fahrenheit are best, and you want humidity levels of at least 50% to see your ferns flourish.
You shouldn't need to fertilize your plants more than once every spring with a fertilizer geared towards acid-loving plants, especially if they're in their preferred organically rich soil.
These undemanding plants don't need a lot of pruning. In fact, trimming back foliage when new fiddleheads appear can impact their photosynthesis abilities. Instead, simply remove dead or damaged fronds as they appear.
Propagating Christmas Ferns
When you already have healthy mature plants, it's super easy to add more Christmas ferns to your collection by propagating them through root division in the early spring. If you want more of a challenge, try sowing ripe spores. Follow these steps to increase your chances of success:
- Spores darken and naturally fall off the underside of the fronds when they're ripe. This usually occurs around October. Don't try picking them off before they are ready, as they'll likely be unviable.
- Gather spores from the fronds with narrower tips (these are more likely to be fertile).
- You can cut off a frond and place it between two sheets of white paper. The spores will drop off over the next 24 hours if fully ripe.
- Make sure you separate any accompanying chaff before sowing the spores. Gently tipping and tapping the paper usually causes the chaff to fall away while the spores remain.
- Dust the spores onto the top of a sterile, moist potting mix suitable for ferns, ensuring they make good contact with the mix.
- Mist the potting mix and, when fully moist, cover the container with plastic and place it in a tray with a couple of inches of water.
- Position the tray in a spot with plenty of warmth and access to indirect sunlight.
- Replace the water regularly. Don't let the soil waterlog or dry out.
- It could take two or three months, but be patient and look for the appearance of a carpet of prothalli (heart-shaped shoots)
- Gently transplant clumps into individual pots filled with moist potting mix when the prothalli are around 1/4 inch tall and leave them uncovered.
- Once the prothalli are around 1 inch tall and fronds begin to appear on them, you can gradually harden them off in preparation to transplant them to their spot in your garden.
- Wait until they are at least 4 to 6 inches tall and the danger of any frost has passed before transferring outdoors.
Common Problems With Christmas Ferns
This might be a trouble-free plant when the conditions are right, but keep an eye out for the issues below—they're usually a sign that you need to switch something up.
If the fronds on your fern look a bit pale and lose their lush green color, it might be getting dry and sun-scorched. Don't forget these plants do well in shadier spots.
They might be more drought tolerant than some fern species, but Christmas ferns like even moisture to thrive. Check the soil if you spot leaves dropping on the fronds, and consider upping your watering schedule (without waterlogging).
Crown rot is one of the most common issues for Christmas ferns. It's usually a result of waterlogging caused by poor soil drainage or overwatering. If you start to see the tips of the fronds turning brown, this can be an early indicator that rot is setting in.
How long can a Christmas fern live?
Choose your spot wisely. With the right care and conditions, you could enjoy these long-lived plants in your garden for as much as 15 years or more.
Where does the common name Christmas fern come from?
There aren't many native ferns that stay green right through the winter holiday season, so it's no surprise this plant was awarded Christmas fern as its common name. Another possible reason is that the individual leaflets on the fronds resemble Christmas stockings.
Can I grow Christmas ferns indoor?
Why not try a Christmas fern if you're looking for a plant for your steamy bathroom? When growing these ferns indoors, the key element for success is providing them with enough humidity and keeping them out of direct sunlight.
You might need to introduce a humidifier or stand the plant on a water-filled tray of pebbles.