Native Plants

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Tuesday - September 08, 2009

From: Accokeek, MD
Region: Mid-Atlantic
Topic: Shade Tolerant
Title: Need help with stabilizing a partial shaded slope in Prince George's County, MD.
Answered by: Jimmy Mills and Joe Marcus

QUESTION:

I have a partial shade sloped area about 40 ft. x 100ft; that is at the top of a natural drainage. Slope is maybe 10%. There is a thin layer of topsoil on top of a heavier clay layer (it was pasture). In heavy rain, surface water will move the leaf litter, exposing hard soil. Logs and the modest slope prevent gullies. My goal is to get enough water retention so ferns (eg NY, royal) would typically last through our summer droughts. Amending the soil, using logs, digging holes or terracing are acceptable but synthetic liners or a cistern and pump are not. I�m happy to follow up on any references you suggest.

ANSWER:

Mr. Smarty Plants is having trouble visualizing the situation you are describing, and determining the question you are asking. If you are asking for suggested plants that will help stabilize a 10% slope that has partial shade, he can do that. If you are asking how to engineer a slope that will support the growth of Osmunda regalis (royal fern) or Thelypteris noveboracensis (New York fern) whose habitats are wet soils along streams and lakeshores, in bogs, and in wet meadows, we're not sure he can be of much help. Given enough shade and soil moisture, these species might work, though.

Your ideas of using strategically placed logs, digging holes (and refilling with rich soil) to capture and hold some water and judiciously terracing all sound reasonable. Any of these actions will create some micro-habitats that will be conducive to growing some native ferns. Fern species that might work for your semi-shady slope are Adiantum pedatum (northern maidenhair), Cheilanthes lanosa, Hairy lip fern, Pellaea atropupurea, Purple cliffbrake fern (if your substrate is limestone), Pteris multifida, Spider brake fern and Asplenium platyneuron (ebony spleenwort) or any of a number of native spleenworts.

I would suggest contacting the Prince George's County Office of the University of Maryland Cooperative Extension which should be able to help you with your drainage issue.

For stabilizing the slope, your best bet is to plant native grasses. They have fibrous root systems that hold on to the soil particles. Here are some suggestions for native grasses plus one sedge that should help control erosion.

Andropogon virginicus (broomsedge bluestem)

Bouteloua curtipendula (sideoats grama)

Bouteloua hirsuta (hairy grama)

Chasmanthium latifolium (Inland sea oats)

Elymus canadensis (Canada wildrye)

Schizachyrium scoparium (little bluestem)

Sorghastrum nutans (Indiangrass)

Tridens flavus (purpletop tridens)

Sedge:

Carex pensylvanica (Pennsylvania sedge)