Septic Safe Evergreen Plants

Trees

• Don't plant trees directly on your septic drain field. The Virginia Cooperative Extension suggests planting your tree at the same distance as the tree's mature height. Septic-safe varieties include hemlocks (Tsuga spp.). These evergreens grow slowly and tolerate a range of soils and thrive in partial shade to full sun. The southern Japanese hemlock (T. sieboldii) grows to 30 feet tall and has horizontal branches covered with light-green needles. It is hardy in the U.S. Department of Agriculture's zones 6 to 8. Other septic-safe choices include small pines, such as the Tannenbaum mugo pine (Pinus mugo "Tannenbaum"). This evergreen grows to 10 feet tall with a 6-foot spread and has a pyramidal shape. It is hardy in zones 2 to 8 and prefers sun to partial shade and well-drained soils. Mugo pines do not produce taproots, which makes them good choices for septic plantings.

Shrubs

• Like trees, shrubs should not be planted directly on top of the septic system, but they can be planted on side slopes or near the foot of the mound. Safe evergreen species include pine shrubs (Pinus spp.). The little mugo pine (P. mugo var. pumilio) grows from 4 to 6 feet tall with an 8-foot spread. It is hardy in USDA zones 2 to 9 and has clusters of bright green needles. The Radiata white pine (Pinus strobus "Radiata") grows to 5 feet tall with an equal spread. It has ascending, light blue-green needles and is hardy in zones 3 to 7. The weeping Japanese red pine (Pinus densiflora "Pendula") grows to 2 feet tall with a 5-foot spread. It is hardy in zones 4 to 7 and has 4-inch-long, dark green needles and red-brown bark. All prefer full sun and well-drained soil.

Ornamental Grasses

• Ornamental grasses have fibrous roots that help hold soil in place over the septic system. Evergreen varieties include kara brocade sedge (Carex dolichostachya "Kaga Nishiki"), a 2-foot-tall grass with upright, arching foliage. This drought-tolerant sedge is hardy in USDA zones 5 to 8 and prefers sun to partial shade. Taiwanese miscanthus (Miscanthus transmorrisonensis) grows to 3 feet tall and has narrow, evergreen foliage. It produces tall inflorescences in midsummer and is hardy in zones 6 to 9. This grass prefers full sun and well-drained soil, but tolerates a range of site conditions.

Ground Covers

• Evergreen ground covers provide year-round color, texture and help prevent erosion, run-off and weed growth and are safe to plant directly on the drain field. Septic-safe varieties include cranberry cotoneaster (Cotoneaster apiculatus), which grows to 3 feet tall and spreads up to 6 feet. This stiff plant has dark foliage and produces pink flowers in summer, followed by a profusion of red berries in fall. It is hardy in USDA zones 4 to 7 and prefers sun to partial shade and well-drained soil. The bearberry (Arcrostaphy los uva-uisi) grows from 1 to 4 inches tall but spreads into a mat of leathery, dark foliage that turns coppery in winter. This evergreen is hardy in zones 3 to 7 and prefers sun to light shade and well-drained, acidic soil. It blooms with white and pink flowers in spring and produces green to red fall fruits. Bearberries tolerate salt and drought.