Planting in an Erosion Control Blanket

[Sara Donohoe]

We have a steep slope (2:1) that we’re using an erosion control blanket on for initial stabilzation and then planting several shrubs and groundcovers. Has anyone ever seen a detail of installing plants (groundcovers, shrubs) in an rolled erosion control blanket? The only details I can find spec seeding, not actual container plants.

BTW – project is located on the east coast.

Thanks!

[Wyatt Thompson, PLA]

I have never done this, but I found two products that claim to support plantings within the mesh.

http://www.greenfix.co.uk/page.php?id=12 and http://www.nagreen.com/erosion-control-products/bionet-ecbs.php

The second link is a US-based company. They don’t have details on their site, but I’m sure you can contact the rep in your area and they can help you out. Of course the success of any system will depend on your need for temporary vs permanent erosion blanket and what kind of sheer stresses and flow velocities you will encounter. Another option might be live staking. Willow is commonly used in the midwest for steambank restoration/stabilization, and can be used in conjunction with other erosion control BMPs.

[Sara Donohoe]

Thanks, the detail from the GreenFix PDF is great. I wonder how large the cross-cut incisions can be made?

[david maynes]

Where on the east coast? Northern or Southern? Southern exposure?

I’ve used low-bush blueberry sod (V. angustifolium) for instant and extremely effective erosion/bank planting. Its likely a bit expensive, but available! Typically harvested in square foot sizes by blueberry farmers in Maine to supplement their income in the slow times of the production year. The gentleman I use will deliver a long distance for a substantial order size. It was around $2.75 – 3/sq.ft delivered a couple years ago. Not sure if it still is. The name of the farm is Sunkhaze, and they’re out of Greenbush, Maine. They worked alot with UMaine developing sustainable harvest methods, etc.

I highly recommend the blueberry sod route. It eliminates the need for an erosion mat, provides instant stability, can be integrated into local farming, has immense wildlife value, is drought tolerant (once rooted in…typically one growing season if planted in spring), helps a northern farmer get through the slow periods, and is stunning in fall color.

Good luck!

[Jason T. Radice]

I’ve never used these. Either I just sod or hydroseed with a stabilizer. And on those kind of slopes with all kinds of plants on the slopes. But it is just like carpet, you cut a hole in them, I imagine you can make the hole as big as you need and then pin it back down. It just seems like a hassle. Remember that if you are putting anything in of size, the plant remains vertical, so you will have a hole on the up slope and mound on the downslope, so you will be removing a lot of the mat, 3′-4′ +. It would look like swiss cheese on my projects, thats why I don’t use them on planted slopes. They are more for large open areas like highways until native veg or a non-stabilized seed can root or a temporary installation to protect the topsoil until you can actually do a real planting on it.

[Sara Donohoe]

I agree with you. The erosion blanket will be there permanently and will most likely have that “swiss-cheese” look. But, what the client wants, the client gets.. right?

Thanks for the advice! It was very helpful.

[Jason T. Radice]

It depends on the size of the project. Depending on the mat, it will actually prevent rooting of the seed underneath, making grow in time much, much longer. I don’t know all the details of your project, but if it were me, I’d try to talk my client out of using it. Even using blown straw would do the same thing. Also, how on earth did you get away with a 2:1 slope? I’ve had one project that had some 2:1, even though the max the town would allow was 3:1. I had redesigned part of the site for greater efficiency (it was a retail project with parking, and whoever did it the first time realy didn’t know how to do it, they even had the slope end at the curb with no flat spot at the top of the slope for planting and a barrier) to reduce the amount of 2:1 and threw it back to the engineer to fix the rest of it of the grading a restamp it. Also keep in mind, if it is a mowed slope, some sucker has to actually maintain and mow it, which is really, really dangerous.

[Wyatt Thompson, PLA]

I must have missed the 2:1 part. Have you considered a short wall to take up some of that grade and flatten your slope? 2:1 is pretty severe. Are you planning to mulch under shrubs or all groundcover? Do you plan to irrigate? What about the poor maintenance person who has to get out there to trim/deadhead; or even the crew that gets to install? If you could flatten to a 3 or 4:1 perhaps you could get away without a mat at all depending on the length of the slope, or at least a biodegradable one that wouldn’t look all holey for the next 20 years.

[Jason T. Radice]

Sorry, take those numbers, reverse them.

 

[Gabriel S. Metz]

In arid regions of the country 2:1 manufactured slopes are common place.  In areas with higher precipitation rate 3:1 is generally the recommended max.  However in overpass construction, slope and shoreline restoration 2:1 can be common to meet and connect to existing stable slopes.

As a general rule, if you are specifying any company’s product like this you should not detail it out in your plans, but instead write “install per manufacture’s specifications and recommendations.” Provide manufacture’s contact info, preferably the rep you are dealing with. You don’t want that liability.

Are you talking about an erosion control blanket (temporary and biodegradable lasts a season allowing plant establishment) or a geotextile fabric (permanent non-biodegradable)?

How long is you slope going to be?  You may need temporary wattles to slow water down and other BMPs.   

I prefer to use the coconut fiber erosion blanket in lieu of straw because I seem to have much better results.  Tensar has a great product I started using for slopes that is 100% organic and biodegradable.  Otherwise Coir, Curlex and Futerra products are pretty standard. One other thing you may need to consider, not all erosion control blankets are created equal.  Some are rated for short term (less than 12 months), and some are rated long term 18 and 24 months.  

If you have a turf or native grass application that requires permanent erosion control, Tensar has Permanent Turf Reinforcement Mats that work great.  Installation is critical for this application.  

If you are looking for permanent geotextile erosion control, take a look at Geotextile Systems by Propex.  They would be one of the industry standard products.   

Tensar and Geotextile Systems by Propex are both good place to start. Both sites have lots of valuable information.

Planting shrubs and trees through erosion control blanket or geotextile fabric is really no different than planting in landscape fabric.   Unless the contractor is doing something stupid, I won’t tell them how to cut a hole or what to install first.  Make sure the contractor is using enough staples and installing blanket or geotextile fabric per manufacture’s recommendations.  Live staking is also common depending on plant species you are planning to use. 

If budget allows you could use a Geocell, Geogrid or Geoweb product!  This all really depends on the length of slope, transitions, benches, how much water is going fall on and flow over the slope area and what drainage steps have been taken.   

[Sara Donohoe]

There is a short retaining wall at one point, but the way the site layed out a retaining wall was not possible (or cost efficient). The whole slope will be covered with groundcovers and the crest will have small shrubs. The mat is biodegradable – we just need it to stabilize the slope until the groundcovers establish. 

[Jason T. Radice]

I went to a presentation this evening at a local college, and the local rep who handles this stuff was there presenting. I’m sold on it, and if I have a project that requires stabilization, will give it a try. They had some pretty impressive local projects.

 

The system is a stabilized compost/mulch that is blown onto the hillside at a depth of 2″. I can be less depending on the application. Seed is added to the mix as it is blown onto the ground. The mulch grabs the slope, knits itself together, and actually filters any water that goes through it. It also actaully accelerates the growth of the groundcover. They also have a berm that takes the place of erosion control fabric/ silt fence that just winds up in a landfill.

 

http://www.rexius.com/erosion_control.html

 

There are a number of installers nationwide.

[Rob Halpern]

Sara,

I would be very careful in selecting what groundcovers to use if the future stabilization is to be left to them. Many groundcovers lack deep roots and with enough rain they will take the slope down with them. Others root deeply and can withstand more stress

[mark foster]

Sara,

We have done this many times.  With a standard soil cloth, the incisions are dictated by the size of hole you need to dig to plant.  

I would second many of the other comments.  Soil cloth will not stop the soil from eroding underneath, so the plants you choose will need to do this job.  And any ground cover which spreads from the root should not be used with soil cloth.

[Author]

Posts