What to plant in shade to prevent soil erosion

Asked March 15, 2020, 4:46 PM EDT

Hello, I need to find some plants to plant on a hillside in our backyard under some huge pine trees to prevent erosion. I would like them to look good (being edible is a plus). It is a mostly shaded area due to the pines.

Montgomery County Maryland

1 Response

If the pines' lowest branches are fairly high up, then they are probably casting what we would call "bright shade," which will leave you with more options (especially for edibles) than heavier shade. The majority of edible plants need full sun (6-8+ hours a day) to thrive and crop well. Assuming you have no deer browsing issues and plant height isn't an issue, there are multiple options for you to consider in either category. Groundcovers are frequently used for erosion control, but even non-spreading perennials and shrubs will work to minimize erosion, especially if planted with spacing such that their mature growth meets above-ground and help block rains from pounding the soil surface.

Edible options:

  • Pawpaw (Asimina triloba) - perhaps the most unexpected choice as these are small trees, but they are understory plants here in the wild (they're native) and can fruit respectably well in shade. Fruits ripen in fall (two trees are needed for cross-pollination); if you don't like the taste, wildlife will be happy to take them off your hands; fruits have a short shelf life but can be frozen whole to preserve them for a bit. Pruning can keep these to as short as 8' tall, but that takes a bit of annual maintenance.
  • Blueberry (Vaccinium corymbosum and V. angustifolium, primarily) and Huckleberry (Vaccinium and Gaylussacia...the latter is our local type) are tolerant of shade and can be found growing in partly-shaded sites in the wild here. They fruit best in full sun, but should survive just fine in less.
  • Elderberry (Sambucus canadensis, or, depending on who you ask, Sambucus nigra canadensis) is similarly best in sun but tolerant of some shade. Fruits are cooked instead of eaten raw.
  • Currants and Gooseberries (Ribes) prefer cooler summers than we have, but can be grown here in partially-shaded sites (instead of the ideal full sun) as a means of keeping them cooler in the heat of the day.
  • Rhubarb similarly prefers cooler conditions and giving it some shade, along with good drainage, can help gardeners grow this successfully. (Otherwise, it's challenging.)
  • Hazelnut (Corylus americanus) is a native nut-bearing shrub, though the squirrels may fight you for the crop.

Ornamental options:
  • Sweetbox (Sarcococca hookeriana humilis) - a slower-spreading evergreen with fragrant late winter / early spring flowers
  • Barrenwort (Epimedium) - low-growing spring-flowering perennial that can have some leaf color changes throughout the year
  • Hardy Plumbago (Ceratostigma plumbaginoides) - spreading deciduous perennial; can have good fall foliage color if getting some sun; relatively long bloom time
  • Leucothoe (Leucothoe axillaris and L. fontanesiana) - evergreen, arching shrub; not quite "running" but will grow wider than tall
  • shady grasses such as Sedges (Carex) and Japanese Forest Grass (Hakonechloa macra) - the former includes some natives and can be evergreen; the latter grows a bit taller but fountains-over; both come in brightly-colored varieties with yellow or white in the leaves
  • Foamflower (Tiarella) - clumping to spreading perennial with masses of white spring flowers and patterned leaves
  • woodland Phloxes (Phlox divaricata and P. stolonifera) - both are native woodland wildflowers; one is fragrant; both are spring-blooming
Neither is, of course, an exhaustive list. A mix of plants would be best for seasonal interest as well as heading-off the likelihood of future pest or disease outbreaks (or stressful environmental conditions that cause damage). Spacing between plants will depend on their individual growth habits and how quickly they will spread.