Asplenium

( ass - PLEEN - ee - um )

At-A-Glance Information

This genus of ferns, commonly referred to as Spleenwort, Bird's Nest Fern, or Nest Fern, includes species which need partial to full shade and regular to ample water to perform well in the landscape. These ferns make great additions to shady beds and mixed borders, and are very commonly grown ornamentals across the globe. They will spread via underground rhizome roots over time. Grow Bird's Nest Ferns in the ground or in containers in woodland, tropical, or informal landscapes. They also make great greenhouse or indoor plants.

Asplenium Species and Varietals

The genus Asplenium includes around 700 species of ferns, and is the type genus member of the plant family Aspleniaceae. The best growing zones for Asplenium vary depending on the species; they are also commonly grown indoors or in greenhouses. For more information, see the descriptions below. To find your zone, click here: Zone Map.

Asplenium adiantum-nigrum (Black Spleenwort, Black Spleenwort Fern)
These plants are mainly found in Africa, Europe, and Asia. Leaf blades are thick and triangular, extending up to 14 inches when mature. Fronds are light green to green and new growth often flushed with golden tones. Individual plants reach up to about 2 feet tall. Best in USDA zones 5-9. Considered to be an invasive species in the southwestern United States.

Asplenium antiquum (Bird's Nest Fern, Spleenwort, Japanese Bird's Nest Fern)
These plants are native to China, Japan, Korea, and Taiwan, where they grow on cliffs, logs and rocks. This is an endangered species in South Korea and Taiwan. Despite its endangered status, however, these are still cultivated as ornamental plants in the nursery trade, and can be grown outdoors year-round in mild climate areas. They are grown as houseplants or greenhouse specimens in cooler climates. Cultivars include 'Crissie', 'Hurricaine' (pictured), 'Leslie', 'Osaka', and 'Victoria'. USDA zones 10-11; hardy to 40 degrees Fahrenheit.

Asplenium australasicum (Bird's Nest Fern, Crow's Nest Fern, Australian Bird's Nest Fern)
This shrubby plant forms a rosette of green to yellow-green fronds that reach between 2 and 3 feet long. They prefer to grow on rocks or as an epiphyte in trees. Many were taken from logged areas, and became popular in the horticultural trade as a result. They are native to Queensland and New South Wales.

Asplenium bradleyi (Bradley's Spleenwort, Cliff Spleenwort)
This rare species of fern is native to east-central North America, and is named for professor Frank Howe Bradley. They produce dark green foliage and have fronds that reach between 2 and 8 inches long when plants are mature. Best in USDA zones 10-12.

Asplenium bulbiferum (Mother Fern, Mother Spleenwort, Hen and Chicken Fern, Pikopiko, Mouku, Mauku)
This species of Asplenium grows best in USDA zones 9-11 or Sunset growing zones 15-17 and 20-24, but can be grown indoors. Native to Australia and New Zealand, this fern has graceful, light green fronds that top out around 4 feet tall. The plant grows to 4 feet wide. Produces fernlets that can be dug up and replanted elsewhere. Hardy to 26 degrees Fahrenheit. Watch out for snails and slugs, as they like to take up residence in these ferns. Hardy to 25-30 degrees Fahrenheit.

Asplenium ceterach (Rustyback Fern, Scale Fern, Stone Fern, Scaly Spleenwort, Finger Fern)
These plants are perennial evergreens characterized by their small size. Fronds measure up to 8 inches long and are green. They are native to western and central Europe, Asia, and Africa, prefer to grow in full sun and require little humidity. This species does well in USDA zones 6a-10. This species is considered invasive in northern Europe and North America.

Asplenium x ebenoides (Scott's Spleenwort, Dragon's Tail Fern, Walking Spleenwort)
This hybrid species is native to eastern North America, and are the sterile offspring between Asplenium rhizophyllum and Asplenium platyneuron. These small evergreen ferns grow in discrete clumps, and are typically grown as ornamentals in greenhouses and gardens. Leaves are unevenly divided. These ferns prefer medium light and high humidity. Frond tips will root where they touch moist soil. Best in USDA zones 4-9.

Asplenium flabellifolium (Necklace Fern, Butterfly Fern, Walking Fern)
These small ferns are native to Australia and New Zealand, and the species was first described by Spanish botanist Antonio Jose Cavanilles. They typically grow from the ground, but can be epiphytic or grow in rock crevices. Fronds reach between 4 and 8 inches long with fan-shaped leaflets. Best in USDA zones 9-11.

Asplenium nidus (Bird's Nest Fern, Nest Fern)
This species is native to tropical southeastern Asia, eastern Australia, Hawaii, Polynesia, India, and eastern Africa. Leathery fronds reach between 4 and 8 inches long and are apple green. Midribs are dark brown to black in color. Central fronds are upright, and outer ones tend to rest on the soil surface. These ferns grow well in USDA zones 10-12.

Asplenium ruta-muraria (Wall-Ruem Wall-Rue Spleenwort)
These plants grow exclusively on limestone and other calcareous rocks, and produce bluish-green fronds that are heavily divided, resembling the foliage of Rue plants. They are native to Europe, East Asia, and eastern North America. Wall-Rue is best in USDA growing zones 5-9 and is hardy down to -20 degrees Fahrenheit.

Asplenium scolopendrium (Phyllitis scolopendrium) (Hart's Tongue Fern)
This variety of Asplenium grows best in USDA growing zones 4-9 or Sunset growing zones 2b-9 and 14-24. Native to Europe and the Eastern United States, this is an odd-looking specimen fern with undivided, strap-like leaves. It grows to form a clump around 2 feet wide, and there are many varieties to collect, with varying shapes, colors, and leaf divisions. These plants need humus-rich soil, amended with limestone chips if the soil is overly acidic. They are hard to grow where water quality is poor. These are great for woodland or rock gardens as well as containers, where they can remain in the same pot for years.

Asplenium trichomanes (Maidenhair Spleenwort, English Maidenhair, Common Spleenwort)
This species has delicate foliage and is native to most of the Northern Hemisphere. They grow best in Sunset zones 2-9, 14-24, H1 and H2 (USDA zones 3-9), and get to 6 inches tall and 8 inches wide. Fronds are bright green and round. These hardy ferns prefer alkaline conditions, so amend soil with limestone chips if necessary. Great for crevices in walls or for shaded rock gardens.

Caring for Asplenium

Asplenium, or Bird's Nest Fern, is best planted in spring or fall; avoid planting during warm weather. These ferns do well in partial to full shade; the amount of sun they can handle depends on the species grown. Check specific growing requirements before choosing a planting site. Space plants between 2 and 5 feet apart for best coverage and airflow. Ensure that soil is well-draining, rich in nutrients and humus, and has a pH of between 5.0 and 7.0 (acidic to neutral). If local soils are particularly poor in nutrients or do not drain well, make sure to amend the planting area with plenty of organic compost before installing. Apply a layer of mulch around the planting area to suppress weed growth, maintain consistent soil temperatures, and to increase soil moisture retention. Water new plantings regularly as they establish a strong root system in their new home. At maturity, these plants perform well in consistently moist soils.

Fertilize yearly in early springtime with an application of 2 inches of compost around the base of plants. Pull mulch back before applying, work the compost gently into the soil a bit, water it in, and then replace mulch. These plants are not heavy feeders, and this should be sufficient to provide the necessary nutrients for the active growing season. Pruning is simple; remove any damaged, diseased, or dead foliage at any time during the growing season. Every few years, these ferns will need to be divided (especially if they are being grown in a cramped border or container). For instructions on how to successfully divide Asplenium ferns, see the Propagation section below. Under ideal conditions, these ferns can survive for 15-25 in the landscape before needing to be replaced.

Growing Asplenium Indoors
Choose a container for your Asplenium fern that is about 2 inches wider than its original nursery pot. Ensure that the container has adequate drainage holes before planting. These ferns do well in a well-draining, organically rich soil. After planting, set the container in a space that is sheltered from dry, cool drafts. They prefer a humidity of between 50% and 80%, which can be imitated by misting twice daily. Provide these ferns with between 14-16 hours of artificial light each day from a growing light or situate them in a space that gets indirect light. Avoid placing in direct sun, even indoors, as this can sunburn foliage. Fertilize with a half-strength balanced liquid fertilizer every month or two during spring and summer. Water whenever the top inch of soil feels dry to the touch. Withhold feedings and lessen waterings in fall and winter when these ferns are dormant. Every few years, these ferns will need to be divided. For instructions on how to successfully divide Asplenium ferns, see the Propagation section below.

Propagation

Asplenium, or Bird's Nest Ferns, are best propagated through division of existing plants. Spores can be used to propagate as well, though doing so requires more specialized knowledge, previous experience, and a suitable medium. To learn more about propagating ferns via spores, see the Propagation module. To propagate your Bird's Nest fern, follow the directions below:

Propagating Asplenium by Division
This type of propagation is relatively simple; you will need a clean shovel, mulch, fresh soil, compost and pots (only necessary if you will be saving divided plants for transporting elsewhere). Division is best done in early spring. To propagate by division, follow these steps:

Using a shovel, dig up your existing plant. Start from the outside and work your way in to avoid damaging the root(s). Once you have worked it up out of the ground, lay it out.
Start to tease apart the roots with your fingers. Once the roots are untangled, separate your plant into segments, ensuring that each one has at least one thick root section attached.
Prepare your pot(s) or new planting site(s) with amended, well-draining soil. You can either bring in new soil or simply amend your existing soil with compost to complete this task. Then, plant your divisions and water thoroughly.
Apply a thick layer of mulch over the new planting to protect it from cold weather as it acclimates to its new home. Then, enjoy watching it sprout in the next growing season.

Problems and Pests

Take care when planting certain species (namely Asplenium adiantum-nigrum and Asplenium ceterach) in the landscape, as they are considered invasive in some areas. Check with local authorities before planting. Asplenium, or Bird's Nest Fern, plants can be susceptible to developing issues with the following pests and diseases: