With up to 100 fronds making up one single leaf, Western sword fern (Polystichum munitum) adds a forestlike appearance to your yard. This perennial evergreen commonly lives at the shady base of tall trees. Taking their natural environment into consideration, plant your fern in a spot that mimics this heavy shade.
Preferring the mild climates of U.S. Department of Agriculture plant hardiness zones 3 through 8, it is best to plant a Western sword fern under evergreen trees or tall shrubs for constant shade throughout the year. Cool breezes and humid conditions also contribute to its success. The intricate, tiny leaves decorating one long fern leaf use their surface area for maximum photosynthesis. Because the fern grows in shade, its leaves must work harder for energy production, compared to full sun plants, to grow healthy and bushy.
Western sword fern does best a slightly acidic soil with a pH between 6.1 and 6.5. This preference mimics the soils surrounding evergreens in forests. The soil should be rich in organic matter, as well as moist and well-draining -- this fern grows vigorously when its roots and rhizomes, or underground stems, have ample soil moisture and air pockets. The fern will not to well in dry or compacted soils, which inhibit root spread and stunt growth.
Aside from choosing a shady spot, Western sword fern is a versatile plant and you can grow it in container or plant it among your favorite trees. Growing to a maximum of 5 feet, when planting in groups, space the plants 2 feet apart. This spacing reduces competition for soil nutrients and moisture while still maintaining dense stand of ferns. Incorporate rocks or shade-loving ground covers around the ferns to create a cool hideaway.
Erosion and Weeds
If you have a small hill that is susceptible to erosion, Western sword fern can help inhibit wind and water erosion. The fern's roots form an intricate, fibrous system. Because of its maze of roots, the soil remains in place even during the heavy rains. You can also plant the fern to help deter weed growth. Healthy, dense fern foliage blocks out the sun, preventing weeds.