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Question:

We have a problem with erosion on a moist, sloping area near our septic field. Our landscaper wants to put in pipes and direct run-off into the woods. Do you have any suggestions for native plants that could help? The area gets afternoon sun on the edge of a wooded area. We are in New Jersey.

Answer:

Directing run-off into your woods is a poor idea and would likely result in yet another problem. Within a septic field, you should not plant woody plants (trees and shrubs), but you can certainly plant shorter woodies on the slope above the septic field, to slow the water flow and prevent erosion. Just don’t plant anything that will grow very tall on a significant slope. A suckering shrub, like Rubus odoratus (Purple-Flowered Raspberry), would do well in the conditions you describe and would support pollinators and birds.

For the septic field itself, perennials and sub-shrubs that “run,” form mats, or re-seed prolifically, can be used. This is a situation where “frisky” natives really shine. With these types of plants, I suggest planting each species separately, preferably in multiple areas, and let them fill in. Some plants will be more competitive than others, so this strategy will help to prevent weaker species from being overtaken.

Plant a diversity of species, with a sequence of bloom from spring through fall. Here are some suggestions of ground-covering plants for moist conditions in a mostly shade area:

Anemone canadensis (Canada Anemone)
Short rhizomatous perennial that will form colonies.  White flowers in spring that attract a number of beneficial insects (nature’s pest control).

Carex pensylvanica (Pennsylvania Sedge)
Short, grass-like plant that often colonizes to form mats. It “blooms” in the spring, providing an early seed source for wildlife. Also a host plant for some skipper species.

Chasmanthium latifolium (Northern Sea Oats)
Cool-season native grass with beautiful seed heads that provide seeds for birds and other wildlife.  Can re-seed prolifically. 2 to 4 feet tall.

Conoclinium coelestinum (Mist Flower)
Medium-sized perennial that spreads by rhizomes. Clumps of small lavender flowers appear in summer. Attracts butterflies and some native bee species.

Eurybia macrophylla (Big Leaf Aster)
Medium-sized native aster that often forms colonies. Named for its oversized leaves, it also sports clusters of violet flowers in late summer through fall. Attractive to butterflies and native bees. Host plant for Pearl Crescent and Silvery Checkerspot butterflies.

Matteuccia struthiopteris (Ostrich Fern)
Tall fern that often forms large colonies. Its fiddleheads are edible and a gourmet treat.

Packera aurea (Golden Ragwort)
Short perennial that spreads by rhizomes and by seed. Heart-shaped basal leaves with yellow flowers on stalks. Flowers attract small bees and pollinating flies.

Phlox stolonifera (Creeping Phlox)
Short mat-forming perennial that blooms in spring with lavender flowers. Best in part shade/part sun. Attracts pollinators, butterflies.

Rudbeckia laciniata (Cutleaf Coneflower)
Tall flowering perennial that spreads by underground stems. Yellow flowers are very attractive to pollinators. Give it room!

Tiarella cordifolia var. cordifolia (Running Foamflower)
Make sure to get the running form, not the clumper.  Spikes of white flowers in spring for pollinators. Beautiful foliage throughout the growing season.

Viola canadensis (Canada Violet)
Short spreading violet with white flowers. Attracts bees and some butterflies and skippers. Host plant for Fritillary butterflies and Giant Leopard Moth.

Xanthorhiza simplicissima (Yellowroot)
Mat-forming sub-shrub that has sprays of small dark purple-brownish flowers and parsley-like leaves. Under-utilized in landscapes.

Run-off and erosion problems are often caused by humans when we remove ground-protecting vegetation. Why not solve the problem with native plants that support the environment, rather than creating even more disturbance with pipes?

Hope that helps!

From Kim Eierman and EcoBeneficial!

Photo: Packera aurea (Golden Ragwort)
Photo credit: Kim Eierman