Landscaping Ideas for a Ditch
Landscaping involving a ditch must necessarily include plants and other materials that are water tolerant or water resistant. When using hard surface materials like stone, brick, concrete or even decay-resistant wood in your ditch landscaping, ensure that those features are well anchored so they will not collapse or accidentally float away during heavy rains. These rains sometimes turn placid ditches into temporary raging torrents. Check with utility companies before digging, as utilities often parallel road rights of way.
Every ditch needs a bridge for getting across in wet weather without getting soaked. This is particularly true of wide ditches that might otherwise have to be waded. The simplest bridge, and a great choice for a rustic landscape with tall grasses and wildflowers, is a narrow plank gangway. Make one out of wide boards nailed across two strong girders long enough to span the ditch and sit well up the banks on either side. Attach the bridge ends to concrete piers sunk into firm ground for support in those high-water times.
Fast moving water is really good at removing loose things in its path -- especially your prized topsoil. Put that problem behind you by planting water-loving plants like cattails (Typha spp); horsetails (Equisetum spp); and other pond-edge plants directly in the ditch. Cover the adjacent banks with irises (Iris spp) and daylilies (Hemerocallis spp). The plantings will not only look beautiful, but they will slow the water draining through your yard and give it a chance to seep down where it will benefit your plants instead of running away with your soil.
Rain Garden Adjunct
Establish a rain garden along the route of your ditch, and use it to create a habitat for birds and other wildlife that are fond of marshes and wet areas. By placing a rain garden near the ditch and planting them together, you gain the benefits of erosion control as outlined above, but you also get the bonus of a larger space farther from the road, where you can plant thirsty trees like willows (Salix spp); maples (Acer spp); and birch (Betula spp), as well as a number of shrubs, including sumac (Rhus spp) and blueberries (Vaccinium spp). The University of Rhode Island maintains an exhaustive database of rain garden information to get you started.
If your ditch runs down sloping ground, it may be necessary to use large, soil-holding rocks -- sometimes called rip-rap -- to slow the water draining through it and prevent erosion, but it need not be unattractive. If the ditch is not on a public right of way and you have complete control over it, consider using the slope to your advantage by creating an artificial stream with a series of waterfall cascades. Family Handyman offers a tutorial for a backyard stream and waterfall that could easily be adapted to the purpose -- just leave out the waterproof liner and recirculating pump so that your ditch continues to do its primary job, draining water from your property.