Erosion control planting guidance - Ask Extension
Hello! we have a steep incline on the side of the house where a retaining wall was removed before we bought it, and I would like to cover it with plan...
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Erosion control planting guidance #470555
Asked July 15, 2018, 11:42 AM EDT
Hello! we have a steep incline on the side of the house where a retaining wall was removed before we bought it, and I would like to cover it with plants for erosion control. Could you please advise if this plan would work?
I want to plant green and gold, moss flox, and ageratum interspersed with each other (I selected them because they are listed on this site as native groundcover good for full sun). I'm also considering doing a row of native wildflowers and grasses interspersed at the bottom of the incline, and some low, creeping shrubs at the top. Does this sound like it could work? How close should they be planted? Should I put fabric around them to limit erosion while their roots are establishing?
Also, the soil is mostly clay. Do I need to mix in any topsoil for the groundcover?
Thank you for your help!
Jessica
Baltimore City County Maryland
Expert Response
Hi Jessica,
In general, your plan and your plant choices sound good. We might steer you away from the green and gold, which, in our experience, does better with some shade.
Planting shrubs at the top sounds like a good idea. You might want to consider Gro-Lo Sumac, which will spread to fill the space. Deutizia gracilis would be another option. Ornamental grasses (switchgrass, little bluestem) will also help to hold soil in place. For this sunny site, you might want to consider some of our native mints such as mountain mint (Pycnanthemum sp.) and bee balms (Monarda sp.). They are spreaders, tolerate full sun and tough soil, and they form a clumpy mass at the base -- again a way to hold soil in place. Black-eyed Susans could also be nice in this situation. Our native Rudbeckia hirta tolerates tough conditions, blooms over a long period, and is a prolific re-seeder.
Your clay soil in this location looks like it could use amending. We recommend adding compost and you can mix it with topsoil. Because your slope is so steep, you will have to hold the soil/compost in place while your plants are getting established. You could lay down Jute mesh soil stabilizer fabric. You could also lay down branches horizontally or add a few large rocks to create ledges for a terracing effect. Think about how your slope will look in the winter when your perennial ground covers die back. Some ornamental grasses can maintain a nice look through the winter months and their long root systems will help to prevent erosion. These are a few options and things to consider. I hope this helps.
ckc
In general, your plan and your plant choices sound good. We might steer you away from the green and gold, which, in our experience, does better with some shade.
Planting shrubs at the top sounds like a good idea. You might want to consider Gro-Lo Sumac, which will spread to fill the space. Deutizia gracilis would be another option. Ornamental grasses (switchgrass, little bluestem) will also help to hold soil in place. For this sunny site, you might want to consider some of our native mints such as mountain mint (Pycnanthemum sp.) and bee balms (Monarda sp.). They are spreaders, tolerate full sun and tough soil, and they form a clumpy mass at the base -- again a way to hold soil in place. Black-eyed Susans could also be nice in this situation. Our native Rudbeckia hirta tolerates tough conditions, blooms over a long period, and is a prolific re-seeder.
Your clay soil in this location looks like it could use amending. We recommend adding compost and you can mix it with topsoil. Because your slope is so steep, you will have to hold the soil/compost in place while your plants are getting established. You could lay down Jute mesh soil stabilizer fabric. You could also lay down branches horizontally or add a few large rocks to create ledges for a terracing effect. Think about how your slope will look in the winter when your perennial ground covers die back. Some ornamental grasses can maintain a nice look through the winter months and their long root systems will help to prevent erosion. These are a few options and things to consider. I hope this helps.
ckc
Thank you so much! This is unbelievably helpful :) I’m still pretty new to MD and I’m excited to get to know the native plants better.
You're very welcome. Two very good resources for learning more about and selecting Maryland native plants are:
Chesapeake Bay Native Plant Center (searchable database)
http://www.nativeplantcenter.net/
Native Plants for Wildlife Habitat and Conservation Landscaping (free PDF)
https://www.fws.gov/Chesapeakebay/pdf/NativePlantsforWildlifeHabitatandConservationLandscaping.pdf
The Maryland Native Plant Society maintains a list of sources for native plants.
https://mdflora.org/nurseries.html
ckc
Chesapeake Bay Native Plant Center (searchable database)
http://www.nativeplantcenter.net/
Native Plants for Wildlife Habitat and Conservation Landscaping (free PDF)
https://www.fws.gov/Chesapeakebay/pdf/NativePlantsforWildlifeHabitatandConservationLandscaping.pdf
The Maryland Native Plant Society maintains a list of sources for native plants.
https://mdflora.org/nurseries.html
ckc
