En Español

Q. Who is Mr. Smarty Plants?

A: There are those who suspect Wildflower Center volunteers are the culpable and capable culprits. Yet, others think staff members play some, albeit small, role. You can torture us with your plant questions, but we will never reveal the Green Guru's secret identity.

Help us grow by giving to the Plant Database Fund or by becoming a member

Did you know you can access the Native Plant Information Network with your web-enabled smartphone?

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
    
 
See a list of all Smarty Plants questions

Please forgive us, but Mr. Smarty Plants has been overwhelmed by a flood of mail and must take a break for awhile to catch up. We hope to be accepting new questions again soon. Thank you!

Need help with plant identification, visit the plant identification page.

 
rate this answer
Not Yet Rated

Friday - July 10, 2009

From: Reedsport, OR
Region: Northwest
Topic: Compost and Mulch, Seeds and Seeding, Erosion Control
Title: Clay hill with erosion problems in Reedsport OR
Answered by: Barbara Medford

QUESTION:

We have a very steep 35-40' clay hill subject to erosion in the Oregon rainy season. How or what do we do to get some kind of vegetation/grass, etc to grow without washing away? We have had mudslides in the recent past. Thank you

ANSWER:

We recommend grasses for controlling erosion because of their extensive fibrous root systems that serve to hold the soil in place.  However, I don't think just throwing grass seeds over the side of your bank is going to work very well.  The seeds need moisture to germinate.  If the moisture comes in the form of rain, it is likely to wash the seeds down the bank into the river before that have a chance to germinate and take root.  There are two possible solutions—an erosion control blanket or pneumatic compost/seed application.  The erosion-control fabric works by slowing the runoff water and allowing sediments to fall out rather than be washed away. Seeds are sown under the erosion-control material and 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 biodegrable material, they will eventually disappear leaving the plants to control the problem.  Many nurseries carry this erosion control fabric. 

The compost/seed application may be a bit more complicated and expensive than you had in mind since it does require a pneumatic blower, or some mechanical means, to spread the compost/seed mix. The US Composting Council offers information about suppliers of compost and compost technology, but we don't really know if this could be a do-it-yourself project.  You might check with a landscaping or environmental consulting company in your area who might have the machinery to do this to learn about the feasibility and expense of applying the compost/seed mixture this way. You can find the names of Landscape Professionals and Environmental Consultants in your area that specialize in native plants by searching in our National Suppliers Directory.

You can go to our Native Plant Database, and do a Combination Search for Oregon, with "grasses" for the Habit, and put in the amount of sun you have on your hillside. You will need to read the soil requirements to be sure the grasses you select will thrive in clay. We are going to choose some samples, but since we don't know what amount of sunlight your bank has, we are not going to choose on a Light Requirement. Follow the plant links to the webpage on each plant, and learn heights, soil types, sun, water needs, etc. on each plant. All those we have selected are native to Oregon and tolerate clay soils. Another resource that is closer to home and probably frequently deals with the same problem you are having is the Oregon State University Extension Service for Douglas County-Horticulture.

Grasses for erosion control in clay soil in Oregon

Aristida purpurea (purple threeawn)

Bouteloua curtipendula (sideoats grama)

Elymus canadensis (Canada wildrye)

Juncus torreyi (Torrey's rush)


Aristida purpurea

Bouteloua curtipendula

Juncus torreyi

Juncus torreyi

 

 

 

More Erosion Control Questions

Erosion Control for Shady Ditches
January 24, 2013 - What plants can you recommend for erosion control along shady ditches in Northwest Indiana?
view the full question and answer

Erosion control in Santaquin UT
August 11, 2009 - I have a hill in my backyard; it is about 40 ft tall and about 80 ft wide. It is probably a 1.5 to 1 slope ratio. I am going to be landscaping my back yard and have top soil put on the hill as well. S...
view the full question and answer

Plants to prevent riverbank erosion in VA
March 05, 2011 - Looking for a plant to prevent erosion on a riverbank on the Rappahannock River in Virginia. Prefer something low, bank is a bit steep for regular mowing but could be mowed infrequently. Riverbank h...
view the full question and answer

Ground cover to control hillside erosion in Illinois
May 04, 2014 - I have seen some other questions regarding native plants for erosion control, but I am looking specifically for plants that will do well on a hill in partial to full shade. I am told the soil in our a...
view the full question and answer

Environmentally friendly native erosion control plants for arid hillside in Austin
July 15, 2006 - Hi, I'm moving into Agave, the new east side development in Austin. It's currently an arid hill with almost no trees and a steep (by gardening standards) hill. As a community, we'd love to...
view the full question and answer

Support the Wildflower Center by Donating Online or Becoming a Member today.
E-NEWSLETTER | BECOME A MEMBER | DONATE NOW | MEDIA | JOBS | SITEMAP | STAFF INTRANET
© 2016 Lady Bird Johnson Wildflower Center