Gardening with Nature
Article by Sigrie Kendrick
Use native plants to help stabilize slopes
It’s just common sense to look to Mother Nature for advice about solving natural concerns on your landscape, like water, steep slopes and sun exposure or shade.
If recent rain sent a torrent of water sluicing down a steep slope on your property, leaving behind a small creek bed full of rocks and gravel and a pile of soil at the bottom, consider planting native and xeric trees, shrubs, grasses and ground covers which will naturally help to stabilize the slope.
Many residential properties throughout the Okanagan have to deal with steep slopes. Our silty soils are notorious for losing stability when exposed to higher-than-normal volumes of water such as intense rainfalls or a sudden rush of water from water line breaks or leaks.
Josh Smith, a director of the Okanagan Xeriscape Association and manager of XEN Xeriscape Endemic Nursery in West Kelowna explains that a cost-effective, low-maintenance and eco-friendly solution is to take advantage of Mother Nature’s suggestions: plant strong-rooted native and xeriscape plants that are adapted to survive and thrive on our slopes—and in our dry environment—to retain the soil and beautify the space.
Plants just after planting to help stabilize a slope on a residential property in Kelowna last year
Developing a naturalized slope-retention system on your property can take several seasons of monitoring but once it is established, it should require zero maintenance, irrigation, or upkeep.
Some key points for getting started include:
- Control the weeds until the trees, shrubs, grasses or ground covers get established. Some invasive species in the Okanagan are virulent enough to take over a slope and hinder the growth of shrubs and trees you have planted or which seed themselves.
- Grass blends or ground-cover are necessary to occlude weeds and provide surface erosion protection. These species help retain the top 10 to 20 cm of the soil.
- Tree and shrub species are what will provide deep, long-lasting, structural support to help stabilize the slope over the long term.
Smith recommends that if you are choosing plant species for slope retention or naturalized areas, go for a walk in your neighbourhood and look carefully at what is growing on natural slopes in your area. This is a surefire way to ensure you select species suited to your soil and moisture conditions.
A year later, the native plants used to stabilize the slope including a yellow-flowered sedum, grey rabbitbrush, nodding onion, a showy fleabane, kinnikinnick and native grass mix are filling in nicely
Resources
There are many wonderful resources available to help you identify native species and learn more about their growth characteristics. Phone apps like iNaturalist and Seek can help you identify plants. There are also several Okanagan-specific plant identification books, including Trees, Shrubs and Flowers to Know in B.C. by C.P. Lyons, and Plants of Southern Interior B.C. by Parish, Coupe and Lloyd, or you can take photos. They can help you look up the plant characteristics in books or on the Internet. You can also take your photos to a native plant nursery for an expert to help you identify the plant.
OXA has an extensive plant database of ornamental and native species.
There are also specialized native plant nurseries like XEN in West Kelowna and Sagebrush Nursery in Oliver, and many other nurseries carry a selection of native and xeric species.
Sigrie Kendrick is a Master Gardener and Executive-Director of the Okanagan Xeriscape Association. She can be reached at 778-363-8360 or by email at exec_dir@okanaganxeriscape.org.
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