By Marianne Binetti
We have clay soils in the Pacific Northwest that drain poorly, so plants drown or rot. We also have patches of gravel, silt, and “glacial till” full of rocks, boulders, stones, and gravel. This type of soil drains so quickly that plants die because the roots just dry out. Also very acid soil under giant native cedar trees can be a challenging site for growing plants.
The traditional solution to any soil problem is improve it with vast amounts of organic matter, or by bringing in topsoil to build berms or mounded raised beds on top of the native soil. This works, but mounds of compost or topsoil are expensive.
In my garden I often use another dirt-cheap solution to the problem. I accept my soil for what it is, and just grow what survives.
Plants that thrive in wet clay soil: I was surprised to see how happy hosta and bleeding heart are in sections of my garden rich with clay. I have since discovered that Vinca minor, spirea, birch, and willow adapt to wet, poorly draining soils as well. I add organic mulch over these plants in early summer. Over time I am building up some great topsoil.
Plants that thrive in gravel and rocky soil: Japanese holly, barberry, 'Blue Star' juniper, and ponderosa and Scotch pine are some of my favorite survivors in gravelly soil that drains quickly.
There is a secret to finding flowering plants that also thrive in the rocky mounds or gravel ribbons that run through a landscape: Look for plants that are called “Rock Garden Plants.” Creeping phlox, artemisia, saxifrage, Iberis, and a host of sedums and succulents delight in fast-draining soils full of rocks and boulders.
Plants that thrive in the acid soil under cedar trees: Native plants, such as our majestic sword ferns, are my favorite choices to plant in the dry shade of cedars. Cyclamen, lamium, vinca, and euphorbias also grow in very acid soil and dry shade.
You don’t need to have fertile, sandy loam to have a great garden. You don’t even need to haul in mounds of topsoil. You just need to plant clay-mates, rock stars, and sword ferns.