Rumohra

( roo - MOW - ruh )

At-A-Glance Information

Commonly called Leather Fern, Leatherleaf Fern, or Seven Week Fern, this genus of ferns includes species which need full sun to partial shade and moderate to regular water to perform well in the landscape. These ferns produce deep green, glossy, finely-cut foliage that is handsome in cut flower arrangements and bouquets. These plants are native to tropical and subtropical areas of the world, and reach 3 feet tall and wide at maturity, spreading by rhizomes over time to form colonies. These versatile ferns can be used as groundcovers, accents in mixed beds or borders, and in containers on patios or hanging baskets. They are also commonly included in cut flower and woodland gardens. The genus Rumohra is a member of the plant family Dryopteridaceae and includes 9 species, one of which (Rumohra adiantiformis) is widely cultivated. These ferns are hardy down to 24 degrees Fahrenheit. Leather Fern does well in USDA hardiness zones 8-11 or Sunset growing zones 14-17, 19-24, H1 and H2. To find your zone, click here: Zone Map.

Caring for Rumohra

Rumohra, or Leather Fern, is best planted in spring or fall; avoid planting during warm weather for best results. These ferns do well in partial to full shade. They ideally like to get bright, indirect light and fronds will scorch in direct midday sun. Space plants between 24 and 36 inches 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 6.5 (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 Rumohra ferns, see the Propagation section below. Under ideal conditions, these ferns can survive for 5 to over 20 years in the landscape before needing to be replaced. They will form clumps over time that can be divided, providing ferns for the landscape indefinitely.

Caring for Rumohra in Containers
Rumohra ferns do well in the ground, but they can also be grown in containers, which can help to curb their spreading tendencies. They can be grown in pots, window boxes or hanging baskets outdoors. Choose a container that is at least a few inches wider and as deep as the original pot, and ensure that it has adequate drainage holes on the bottom to allow excess water to drain away from the root zone. At maturity, these ferns grow well in a 2 to 3 foot tall and wide container. Fill with a well-draining potting mix. Water regularly as the plant establishes itself in its new home. Once established, these ferns prefer to receive regular water. Rumohra plants grown in containers will need more frequent irrigation than those grown in the ground. As a general rule of thumb, water whenever the top few inches of soil feels dry to the touch. Prune to remove dead, damaged, or diseased foliage at any time during the growing season. Every few years, check the bottom of the pot to ensure that the plant is not outgrowing its root space. If roots are growing through the drainage holes in the bottom of the container, it is a good indication that it needs to be potted up; choose a slightly larger container and repot. For instructions on how to successfully divide and repot Rumohra ferns, see the Propagation section below.

Growing Rumohra Indoors
Choose a container for your fern that is about 6 to 8 inches wide and just as deep. 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 bright to medium, indirect light. A spot inside of an east or north-facing window is ideal. Avoid placing in direct sun, even indoors, as this can sunburn foliage. 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 Rumohra, see the Propagation section below.

Harvesting Rumohra
Rumohra ferns are very popular additions to cut flower arrangements and bouquets as greenery or filler. They produce large, glossy dark green leaves with a symmetrical triangular shape. Do not use floral food with these ferns, as it can cause the fronds to turn yellow. The best time to harvest these ferns is in the morning, after dew has dried but before the heat of the day sets in. Choose fronds that are fully expanded, mature, and dark green with a firm texture. Using sharp, clean shears, cut the frond close to the rhizome or ground level. Immediately drop harvested fronds into a bucket of clean, cool water to prevent rapid moisture loss and frond curling. The fronds can last for between 7 and 21 days under proper conditions.

Propagation

Rumohra, or Leather Ferns, are best propagated through division of existing plants or root cuttings. 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 Leather fern, follow the instructions below:

Propagating Rumohra 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.

Propagating Rumohra by Root Cutting
To complete this method, you will need a clean trowel, clean pruning saw, extra pots, and well-draining soil to fill the pots. To propagate your fern by root cutting, follow the instructions below:

Identify the fern you're going to take your root cutting from. Ensure that the plant has had a good watering the night before, as this will increase the odds that your root cutting will take. Start by loosening the soil around the plant with your shovel, working your way inward to avoid causing damage to the roots. Once you've gotten your clump out of the ground, lay it out on its side.
Identify a root (or a few roots, if the plant is a large size) that you'd like to use. Ensure that each root segment has a frond attached, and trim the root section to fit into its new pot.
Fill your pot(s) with sand-amended soil about 3-4 of the way up, and then place your cutting on top. Cover with about a half inch of soil. Water generously and ensure that adequate drainage is occurring. Place the pot in an area that receives bright, indirect light and stays at a temperature of around 70 degrees Fahrenheit. Your root should begin to grow a new plant in about 3-5 weeks.