The bold texture and shiny dark-green leaves of holly fern (Cyrtomium falcatum) make an easy-care addition to shaded gardens. The thick, leathery leaves tolerate windy locations without tearing, and are not bothered by salty air if you want to use them in coastal gardens. Native to Africa and Asia, this plant is also called Japanese Holly Fern. These ferns work well as a border plants, used in mass plantings as a ground cover or in a woodland setting.
Holly ferns are hardy outdoors in U.S. Department of Agriculture plant hardiness zones 6 through 11. They will stay green year-round in zones where it doesn't freeze and the fern is protected from frost. Otherwise, they lose their leaves each winter, then leaves return in spring.
Shaded locations are best, though holly ferns will tolerate partial sun. Plants rarely require division, and you don't need to worry about them becoming invasive. The roots take up a relatively small growing space, so holly ferns can be used in small rock gardens and thrive when planted under trees and tall shrubs.
Holly ferns prefer loose, fertile soil with high levels of organic matter. An acidic pH between 4.0 and 7.0 is preferable. In locations with sandy or clay soil, spread a 2-inch-thick layer of composted pine bark or other organic matter over the soil surface where you'll be planting the ferns. Work this into the soil to a depth of 10 inches.
Though ferns need moist soil, soils that stay boggy will rot the roots. Ensure the soil is well-drained enough that the ferns are not standing in water. Holly fern is drought-resistant, but appreciates supplemental water when there's no rain. Supply up to 1 inch of water per week to keep them actively growing.
Though the roots will fit in cramped locations, the top part of a holly fern can grow 2 to 3 feet tall and wide. Space plants at least 2 feet apart to give the fronds enough room to spread out.
Plant ferns in the spring after the last frost date in your area, so they have plenty of time to establish a root system before winter. Dig a hole slightly larger than the pot size and the same depth. Water each fern before removing it from the container. If the plants are pot bound, gently tease the roots apart with your fingers before planting.
Set ferns in the soil at the same level that they were growing in the containers. For the first year, water the newly planted holly fern with 1 inch of water per week, or as needed to keep the soil moist. This will help establish a deep root system.
Holly ferns grow well in containers, and even work as houseplants. When growing ferns in containers, choose a moisture-retentive potting mix that contains peat moss. You can make your own fern potting mix by combining equal parts weed-free garden soil, clean sand and peat moss.
Water indoor ferns often enough to keep the potting soil moist, but not water logged. Holly ferns require less humidity than other potted ferns, though they will appreciate a light misting with room temperature water in dry rooms.
Holly ferns like moderate or cool indoor temperatures and indirect sunlight. Avoid placing indoor ferns near a south- or west-facing window unless there is a lace curtain or other plants to shade them from direct sunlight.
- University of Florida IFAS Extension: Holly Fern
- University of Florida IFAS Extension: Holly Fern Dresses up a Shady Corner
- NC Cooperative Extension: Crytomium Falcatum
- Clemson Coopertive Extension: Hardy Ferns
- University of Illinois Extension: Gardening With Perennials -- Planting and Transplanting
- University of Vermont Extension: Growing Ferns Successfully Indoors
- Purdue University Cooperative Extension Service: Ferns for Indoors
- Photo Credit Timothy_Wang/iStock/Getty Images
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