Question
Hi Sean.  Not sure if you're the right person to ask.  I have a little house perched about 12 feet away from a high slope; the street, heavily travelled, is right below.  Last year PennDOT came in and scraped away the bank and all the vegetation, leaving an enormous erosion problem.  They put burlap netting from the top of the slope to the base, then hay, but did not relace any stones or soil, leaving enormous gaps under the burlap.  This year, due to high rainfall, the slope is eroding even more; rocks are falling onto the highway, the burlap netting broke and the plants that were at the top are showing their roots and beginning to topple down the slope.  Water is percolating out through the slope.  Of course, I will contact PennDOT, but what plants and bioenginerring can I use to begin to stabilize this slope and my house?  My pockets aren't too deep either!  Thanks so much.

Answer
First off I would consider hiring a professional registered Landscape Architect by the hour to visit your site and write a field report documenting the conditions and making an official recommendation. ($75-150/hr) Second, depending on what he/she says, I would consider sending a certified letter to PennDOT with a copy of the report and threaten them with a law suit if they do not correct the situation within say 90 days. If PennDOT scraped the area it may not be your property so check to be sure before working in it. It is probably in the right of way, and not on your lot.

There are many plants that may help your situation. I would look for an aggressive ground cover. The best thing for rapid cover will be some sort of grass mix. Lespedezea grass is always a good for DOT use and is probably the best thing if there is a lot of sun.I believe there are also some juniper that will do well in your area but planting this trough "jute" netting is not easy and its relatively slow growing. Vinca ground cover may work also in your situation. You want something that will do well in sunny, salty, road side conditions that spreads and covers rapidly.

Another option is a mass of perennial flowers and grasses. This can look great while performing a valuable function.

I suggest you contact the DOT department ASAP, as they would have a landscape/maintenance department that has a list of good suitable materials.

Best of Luck

Sean J Murphy, LA,ISA, LEED AP
Please check out my blogs and articles on landscape topics like this on my websites.
http://www.seanjmurphy.com
http://amenityarchitects.com