How to Grow and Care for Autumn Fern

Among the hardy ferns, autumn fern (Dryopteris erythrosora) stands out because of its eye-catching seasonal foliage. In the spring, the newly emerging papery fronds are bright coppery-red to orange-red. This stunning fall-like color, which gives the fern its common name, persists for several weeks. As the season progresses, the color of the glossy fronds changes to an equally bright green. 

The fern has a compact size, which makes it suitable for small spaces. It is not a fast grower; it takes five years for autumn fern to slowly spread to its mature size of about 2 feet. The best time to plant autumn fern is in the fall.

Autumn Fern Care 

The filigree look of autumn fern foliage is deceiving—this is an easy-to-grow fern, Here are the main care requirements for growing autumn fern:

• Plant autumn fern in a shady location with soil that is high in organic matter and acidic.
• Water the newly planted fern until it is established. Established ferns should be watered during dry spells.
• Apply a generous layer of mulch around the base to keep the soil moist in the summer and insulate the roots in the winter. 
• Fertilize once a year in the spring.

Light

Autumn fern needs to be planted in a location where it gets dappled sunlight or partial or full shade.

Soil

The soil should be similar to conditions in the fern’s native woodland habitat in eastern Asia: acidic with a pH below 6.0, containing a high amount of organic matter, consistently moist but with good drainage. 

Water

Until it is established, during the first growing season, a newly planted autumn fern needs regular watering in the absence of rain. In climates with regular rainfall, watering is not necessary. In drier climates, or during dry spells or extended droughts, water the area around the plant slowly and deeply to keep the soil moist, ideally with a soaker hose.

Temperature and Humidity

Autumn fern grows in a fairly wide climate range; it tolerates both freezing winter weather and does well in moderately warm summer temperatures and high humidity. However, it does not do well in hot or dry weather, and it is especially vulnerable to drying winds that parch the soil.

In the lower range of its climate zone spectrum, in USDA zones 5 and 6, the foliage might die back during the winter but will bounce back in the spring. 

Fertilizer

Autumn fern that has been planted in soil high in organic matter only needs a springtime application of a complete all-purpose fertilizer. 

Types of Autumn Fern 

The only known variety of autumn fern is ‘Brilliance’, a cultivar whose new fronds are a brighter coppery-red than the species. New colorful fronds appear during the entire growing season and gradually turn to deep green as they mature.

Pruning

Autumn fern does not require pruning, in fact, when the old fronds wither over the winter, it is important to leave them on the plant. When they die down in early spring to make room for the new fronds, you can remove them for a neater appearance but be careful not to damage any new growth at the crown. 

Propagating Autumn Fern

Autumn fern is best propagated by division. Propagation by spores is possible but lengthy and involved and thus not recommended. You’ll need a mature specimen, one that is showing a bare center which is a sign that the plant needs to be divided to rejuvenate it.

1. In the spring, when you see the first new fronds emerge, dig out the entire fern and all its roots (rhizomes) with a shovel.
2. Separate it into smaller segments using pruners. Make sure that each segment has at least one growing tip with sprouts on it from which the fronds will emerge.
3. Dig a hole slightly deeper than the root system. Add a few handfuls of organic matter and place the segment in the hole. Backfill with soil and gently press down on the soil. Water well and keep the new fern well-watered in the absence of rain until you see new growth and the plant is established.

Potting and Repotting Autumn Fern

Autumn fern is suitable for potting as a houseplant or for a patio or balcony container plant. Select a pot, preferably clay or terracotta, with large drain holes. The pot needs to be tall and wide enough to accommodate the entire root system of the fern.

Because ferns prefer rich soil, rather than using just potting mix, fill it with a combination of all-purpose potting mix and compost. Water it well and keep the soil moist at all times. Especially when you keep your fern outdoors, you need to be diligent about watering and never let the soil dry out. Container plants also need to be fertilized more often, about once a month during the growing season. 

Repot the fern when it becomes root-bound, which is often indicated by smaller fronds.

Overwintering

When planted in garden soil, autumn fern does not need to any protection during the winter. As a potted plant, however, its roots are not sufficiently protected from winter chills. While there is no need to bring the containers indoors, provide additional insulation around the container. You can either place the container in a larger pot or box and fill the space with mulch or sand, or wrap the sides of the container with bubble wrap, or burlap and an additional layer of plastic wrap.

Common Pests & Plant Diseases 

Autumn fern attracts mealybugs, scales, and aphids but these are rarely a danger to the plant’s health. It is not prone to serious pests or diseases. Autumn fern is relatively unbothered by wildlife. Rabbits and deer usually leave autumn fern alone.

Common Problems with Autumn Fern

When the fronds of autumn fern become shriveled, brown, or discolored, the cause is usually sunburn. This happens rather quickly within a few hours, usually when new plants are moved to a location with too much sunlight or when plants that were grown in a greenhouse have not been properly hardened off. It may also happen to an established fern in your yard when you prune or cut down a tree or shrub nearby that used to cast shade on the location but is now more exposed to the sun.