By Deepa Sanyal

Master Gardener℠ volunteer in Chatham County

An ideal garden topography is slightly raised in the center and tapers gently toward the outside of the garden preventing water from collecting and creating soggy soil.

Consider the topography of your site as you plan your garden. The natural lay of your garden may contain low lying areas-the bottom of a hill or just a depression in the ground that collects water. Other topographical features that make for wet conditions are a natural underground spring or soil types with different drainage characteristics. (Sandy soils drain the fastest, silty soils drain moderately well, and clay soils retain the most water). It is also possible that the ground may be wet seasonally-dry during the summer but soggy from fall to late spring. To borrow from Michael Pollan's well-known quote, plants, trees, shrubs, and groundcover all need water, but not too much.

There are several ways of mitigating wet areas and/or low laying areas in your garden. You can fill in the low-lying areas and create raised beds by spreading garden loam (amended with organic matter such as compost or manure) over the gardening area so that the center of the garden is 2 to 3 inches higher than the soil in the surrounding areas. This creates a slight slope away from the center of the bed and discourages water collection in the middle of the garden after heavy rains. Rake the area smooth, maintaining the raised center and sloping sides. Plant, as usual, the flowers or plants you wish to grow. In severe cases of soggy landscape, a drainage system can be installed to intercept and convey water away from the wet area. Dry wells and French drains can also be incorporated.

Or, or you can go with the flow/lay of the land and plant a rain garden or bio-swale to manage water on-site. A rain garden is a shallow ground depression planted with native and regionally appropriate flowering plants and grasses that trap runoff water. They also support wildlife, including pollinators like bees and butterflies. A bio-swale is a landscape element consisting of a shallow drainage course with gently sloped sides, meant to slow the movement of water and filter out pollutants. The swale can be planted with vegetation, often grasses and groundcovers, or with a combination of plants, rocks, and compost.

For more information on rain gardens, visit: Chatham Rain Gardens