Any landscape designer or contractor who’s worked on a property with grade issues knows how vitally important it is to address those slopes from the very beginning — the greater the rise over run, the more issues you can have. From soil degradation to residential water damage, clogged drainage structures, and driveway instability, the laundry list of potential problems is great.
When you’re called upon to address erosion issues you have a number of tools in your tool belt and can find many of the plants and supplies you need via LandscapeHub suppliers.
Here’s a rundown of the most popular and widely used options, from relatively easy fixes to more intricate engineering.
Install a rain garden
Rain gardens have been trendy landscape additions over the past few years, but they do have a purpose and can be an elegant solution for low areas where water accumulates. Rain gardens are shallow depressions (anywhere from a few inches to a couple of feet deep) that soak up rainwater, allowing water to infiltrate the surrounding soil rather than running off. Plants need to be able to tolerate standing water but also periods of drought. The advantage of planting perennials, trees, and shrubs over lawn grass? They can soak up 30% more water than grass.
Great rain garden plant choices for the east coast include:
· Nyssa sylvatica (black gum)
· Celtis occidentalis (hackberry)
· Hydrangea arborescens (smooth hydrangea)
· Physocarpus (ninebark)
Create dry creek beds
Again, if your slope is gentle, this is a great solution on its own or combined with other erosion-control features. Study where the water is flowing and pooling, and design a dry creek bed using various aggregate sizes (from natural stone boulders to gravel) to positively direct water.
Add a drain system underneath the dry creek bed if necessary to ensure rainfall and water flow is dispersed correctly. When designed and installed correctly, dry creek beds not only assist in proper drainage, they are stunning landscape features as well.
Add soil-stabilizing plantings
Rainwater falling on bare soil quickly dislodges soil particles, making it easy for ground to erode, particularly on slopes. Add appropriate plantings to protect the soil naturally — the right plants diffuse the rainwater and assist in binding soil together underground. Look for plants that have large portions of fine roots that spread over a wide area, such as groundcovers and creeping shrubs.
Recommended erosion control shrubs for the east coast:
· Hypericum (St. John’s wort)
· Ilex glabra (inkberry)
· Juniperus (juniper)
· Syringa (lilac)
· Rhus aromatica (fragrant sumac)
Create retaining walls or terraces
If the rise over run is 2:1, you’ll likely need to consider creating retaining walls or broad terraces. If you’re new to these structures, you’ll need to be sure your work is in line with your city’s building permits. However, if the wall is less than 3’ high from the ground to the top of the wall, you are less likely to need a permit. Higher walls or multiple walls will likely require some hoop-jumping. It’s worth it to keep the whole site from collapsing, though.
A retaining wall doesn’t have to be made of cement blocks. Natural stone drywall products are perfect for building beautiful retaining walls. If the budget is tight, check out natural stone veneer for a more polished finish.
If you’ve addressed the grade issues properly and the plants are in place, erosion can still occur until the new plantings mature enough to do their job. Hydroseeding native plant seeds can solve that problem and can work particularly well for large commercial projects as well. Another benefit? It increases the plant diversity of the area, elevating the health and vigor of the overall landscape.
Considering using geotextiles
After slopes are graded, and before and after planting, the soil is vulnerable to erosion. Geotextiles can come in handy here — these manufactured materials (coir mat, jute mesh, burlap, etc.) are pinned to the slope and are biodegradable, allowing contractors to plant through it. As it begins to degrade, the plantings will take over, with both elements/treatments overlapping to ensure adequate erosion control.