Microsorum

( my - kro - SOH - rum )

At-A-Glance Information

This genus of tropical ferns includes species commonly called Kangaroo Ferns or Crocodile Ferns. They grow from creeping rhizomes; some species are lithophytic (they grow from rocks), others are aquatic. These highly adaptable ferns are native to tropical and subtropical regions around the globe and are typically used as groundcovers, in shaded mixed beds and borders, or as accent plants. They also do well in containers, and some species can be included in aquariums.

Microsorum Species and Varietals

The genus Microsorum includes 43 species and is a member of the plant family Polypodiaceae. They grow well in USDA hardiness zones 9 through 11, and can be grown indoors or in greenhouses in cooler zones. To find your zone, click here: Zone Map.

Microsorum grossum (Serpent Fern, Wart Fern, Maile-Scented Fern, Musk Fern, Lua'e Fern)
This species of fern is native to tropical areas in Oceania and Australia. These ferns are commonly found in disturbed areas, mangroves, and other upland habitats. Individual ferns can reach up to 1 to 3 feet tall and wide, and commonly form clumps. Green leaves usually have more than five lobes and have a sweet smell to them when fresh that is similar to Vanilla or Almond. Foliage is used in lei making. This species is considered invasive in south Florida and the Hawaiian Islands.

Microsorum punctatum (Fishtail Fern, Climbing Bird's Nest Fern, Dwarf Elkhorn Fern, Wart Fern, Fishtail-Strap Fern)
Used in traditional medicine, this species of fern grows epiphytically as well as terrestrially and is native to Singapore. Underground rhizome is small, and spores are small and reddish. These ferns reach up to 1 to 3 feet tall and wide at maturity. Cultivars include 'Grandiceps' (with repeatedly forked fronds), 'Crested Fantasy' (with heavily twisted fronds), 'Dragon Wing' (with heavily crested fronds) and 'Green Flame' (dwarf, Elkhorn-like form with wavy, irregular cresting). This species is considered invasive in Australia.

Microsorum scolopendria (Monarch Fern, Musk Fern, Maile-Scented Fern, Breadfruit Fern, Wart Fern, Laua'e)
This tropical fern is native to the Western Pacific Rim and South Pacific. Introduced to Hawai'i in the late 1910's, it has naturalized itself on the islands. When leaves are crushed, they emit a scent reminiscent of a native Hawaiian flowering vine, Maile. These ferns can reach up to 1-2 feet tall and twice as wide. This species is considered invasive in south Florida and Hawai'i.

Caring for Microsorum

Microsorum is best planted in spring or fall; avoid planting during warm weather. These ferns do well in partial to full shade. 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 5.5 and 7.0 (slightly 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 these ferns, see the Propagation section below. Under ideal conditions, these ferns can survive for 5 to 10 years in the landscape before needing to be replaced.

Growing Microsorum Indoors
Choose a container for the 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

Microsorum, or Crocodile 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 Crocodile Fern, follow the directions below:

Propagating Microsorum 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

Certain Microsorum species are considered invasive in some regions; see the species descriptions above for more information. Check with local authorities before planting. Microsorum plants are susceptible to the following issues and pests: