Explore Plants

Share

Ask Mr. Smarty Plants

Ask Mr. Smarty Plants is a free service provided by the staff and volunteers at the Lady Bird Johnson Wildflower Center.

Search Smarty Plants
    
 

Can't find the answer in our existing FAQs, submit a question to Mr. Smarty Plants.
Need help with plant identification, visit the plant identification page.

rate this answer
Not Yet Rated

Thursday - December 22, 2011

From: Cary, NC
Region: Southeast
Topic: Plant Lists, Erosion Control, Grasses or Grass-like
Title: Plants for a bare clay slope in North Carolina
Answered by: Nan Hampton

QUESTION:

Hi - I live near Raleigh North Carolina (border of the coastal plain and Piedmont). I have about 1/2 acre that was excavated for a geothermal heating/cooling system and now I need to stabilize it and establish some kind of growth ASAP. The excavated and the surrounding area (another 1/2 acre, or so) is old pasture. I bush-hog it infrequently to keep the bushes and trees from taking over. I'd like to establish native grasses and wildflowers and keep it open as it is my only non-wooded area and it allows a nice view to a pond. After grading it is mostly clay on the surface. It is also on a slope and to keep the silt from draining into the pond I spread straw and annual rye grass seed. That seems to be helping for now, but I am also concerned about that taking over. How can I establish native grasses and flowers and what can I do till Spring to keep it from turning into even more of a mess? What recommendations do you have for species and seed suppliers? Thanks, Jeff

ANSWER:

First of all, you will want to either mow or plow under the annual rye grass before it sets seed.   Otherwise, it will drop its seeds to germinate and come up again next season.  Hopefully, the straw you put down doesn't have seeds of unwanted species in it.  For plant recommendations, let's start with grasses since the extensive fibrous roots of grasses are very effective in holding soil in place.  Native warm weather grasses will come up from seed after the weather warms in the spring.  The seeds can be planted now beneath erosion control cloth (see comments below) or you can wait until early Spring. Here are some species native to your area of North Carolina that will grow in clay:

Andropogon gerardii (Big bluestem)

Elymus canadensis (Canada wild rye)

Elymus virginicus (Virginia wildrye)

Eragrostis intermedia (Plains lovegrass)

Muhlenbergia emersleyi (Bullgrass)

Muhlenbergia schreberi (Nimblewill)

Panicum virgatum (Switchgrass)

Poa arachnifera (Texas bluegrass)

Schizachyrium scoparium (Little bluestem)

Sorghastrum nutans (Indiangrass)

Tridens flavus (Purpletop tridens)

Tripsacum dactyloides (Eastern gamagrass)

Depending on how steep your slope is, you might benefit from using some sort of erosion control blanket. The erosion-control fabric works by slowing the runoff water and allowing sediments to fall out rather than be washed down into your lake. Seeds sown under the erosion-control material grow up through the matting when they germinate. You can also insert plants into the soil by cutting through the matting. The roots of the plants that are growing through the erosion-control material anchor the soil to stop the erosion. If you use erosion-control blankets made of biodegradable material, they will eventually disappear leaving the plants to control the problem.  Most nurseries carry these erosion control blankets. 

You can choose wildflowers to go with the grasses from the North Carolina Recommended list of commercially available native plant species suitable for planned landscapes.

Our National Suppliers Directory can be searched for nurseries and seed companies specializing in native plants for your area.

From a quick preliminary search, I found Lumber River Native Plants in Gibson, NC with several of these grasses for sale.   Mellow Marsh Farm, Inc. in Siler City, NC has several mixes of grass and wildflower seeds that would be suitable.  There are more nurseries and seed companies that I didn't investigate.

There are several How to Articles under Large Scale Wildflower Planting (for instance, Meadow Gardening) that should have useful information for your project.

Below are photos of some of the grasses from our Image Gallery:

 

From the Image Gallery


Canada wild rye
Elymus canadensis

Plains lovegrass
Eragrostis intermedia

Switchgrass
Panicum virgatum

Texas bluegrass
Poa arachnifera

Purpletop tridens
Tridens flavus

Eastern gamagrass
Tripsacum dactyloides

Virginia wildrye
Elymus virginicus

More Erosion Control Questions

Plants to hold a slope in Northern New York
December 10, 2009 - I'm looking for native (South shore, Lake Ontario) plants to slow erosion on a steep, 20 foot bank. They don't have to be decorative (although flowering plants are always nice), but they should SPRE...
view the full question and answer

Ground cover for a bank in PA
April 28, 2012 - I live in Landisburg, PA, (zone 6). I need to find some ground cover for a primarily full sun bank that is roughly 10-12' down over the embankment and up to 100' long. This area wraps around our po...
view the full question and answer

Erosion Control for a NC Clay Slope
June 06, 2013 - Hi, We have a large slope on the road edge of our property that has been gradually eroding with spring rains (NC red clay). We would really like to plant something for erosion control but the bank is...
view the full question and answer

Need a pretty ground cover to control erosion in Rigdeway, SC.
June 09, 2012 - What is a fast, pretty ground cover blanket to control erosion on steep hill. gets full sun.
view the full question and answer

Plants for pond, for incline and area with poor soil
April 23, 2012 - I have three plant recommendation questions for Austin, TX. 1. I have a large pond that I would like to put native aquatic plants in. What are some hardy aquatic natives I could put in? The pond ...
view the full question and answer

Smarty Plants's Facebook profile Support the Wildflower Center by Donating Online or Becoming a Member today.

Mr. Smarty Plants wants you to be his Facebook friend. Click the Facebook icon to add yourself to Mr. Smarty Plants list of friends.