During the hot dry months of late summer, one of the last things that enters our minds is wet soil. However, heavy watering sometimes reveals low areas of our lawns and gardens where water gets trapped and stands for long periods.
A knock-out rose in my garden is dying of root rot because it’s in a place that floods. This wasn’t the case when I planted it years ago, but a newer bed just slightly uphill from the rose has routed more water next to the raised edge of the patio where the rose is slowly drowning.
I discovered the damage and its cause when I was pruning last February and a large section broke off at the base. Arborist Wes Hopper says, “I’ve never met a tree that wanted to die.” I think the same can be said for this big shrub of mine, but without intervention it will probably last only another year or two.
Gardeners take several approaches to managing low areas. Sometimes it works to build the area up by adding more soil. In a low section of lawn, you can gradually add small amounts of topsoil and wait until the grass comes up through it before adding another layer, or you can add a large amount all at once and replant the area. When you add soil, remember the excess water still has to go somewhere, so be careful not to route it to an even more undesirable place.
Adding soil won’t work for my rose because it would bury the roots even deeper. So another option is to route the water away by digging a trench for run-off. When a trench is in an area where it could cause a turned ankle, a dry creek bed is a safer alternative. Create this by filling a wide trench with small river rock. The rocks make the trench more visible and raise it nearer ground level where water can still filter down and away.
There’s a third alternative for the lazy gardener who would rather do research in a cool house than move dirt around on a hot day. The Southern Gardener’s Book of Lists, one of my favorite resources, includes a section on shrubs that thrive in wet soil. It lists 15 possibilities including spicebush, sweetspire, red-twig dogwood, anise, and an osmanthus called devilwood.
With this list, I can learn the specifics for each shrub using books or going online. Some will get too large without heavy, frequent pruning. Some are evergreen, and some shed their leaves. Some will fare better than others in the shade on the north side of our house. Some have showy flowers or small fragrant ones.
In the year or two before the rose finally gives up, I can narrow the choices. If they’re worth planting here, I will be able to see examples at the Botanic Garden, Dixon, or Lichterman. Instead of changing the site to suit the plant, this time I can change the plant to suit the site.