"The soil is made of butterfly wings, dinosaur teeth, pumpkin seeds, lizard skins, and fallen leaves.
Put your hands in the soil and touch yesterday, and all that will be left of tomorrow shall return
so that new life can celebrate this day." -Betty Peck
Soil is a wonderful thing. It grows our food, anchors our trees and provides a foundation under our feet. But it sure can be hard to work with if it’s not the soft, crumbly loam that many plants prefer. It’s amazing that anything grows in some of the soils here in the Santa Cruz mountains. Some folks garden in an ancient sea bed of sand and there are others who have such heavy clay in their gardens that you wonder how anything survives. Recently I helped plant in the dense clay of Garrahan Park in Boulder Creek and I dedicate this column to those of you with similar inhospitable soils.
The soil in Boulder Creek required a pick ax to break up enough to plant. Sound familiar? Although rich in nutrients it needed compost in many areas to provide the environment necessary so beneficial microbes, worms and other critters could do their work and aerate the soil. A thick layer of mulch will be spread over the soil by The Boy Scouts to preserve the structure and prevent it from packing down again.
There are many plants that are tolerant of clay soils and plant selection is half the equation. The park chose mostly California natives that won’t need fertilization or pruning, can be eventually weaned from irrigation and will provide food for the birds and visiting children. Juncus, a type of grass, red-flowering currant, redtwig dogwood, California rose and western redbud will be the stars of the park in the wet, clay soil. The drier side of the park was planted with deer grass, toyon, California rose, huckleberry, coffeeberry , ceanothus, native honeysuckle, vine maple, native iris and California fescue grass.
I’m sure the park will be the crown jewel of the area and hopefully you will come to visit and see the progress of the plants. Kinda like a local demonstration garden in the San Lorenzo Valley.
There are plants from similar environments in other parts of the world that would also do well if you garden in heavy soil. One of my favorite trees for these conditions is the strawberry tree. Also hackberry, ash, gingko and paperbark trees work well also. Shrubs to try include flowering quince, bottlebrush, Australian fuchsia, smoke tree, escallonia, pineapple guava, mahonia, osmanthus, Italian buckthorn, elderberry and vitex. Easy perennials for clay soils are yarrow, bergenia, carex grasses, fortnight lily, coreopsis, echinacea, nepeta, salvia, teucrium and verbena to name just a few.
If you’re not familiar with some of these plants it’s easy to see what they look like by Googling images. It’s what I do to see a plant full grown and not just a line drawing or a close-up of the flower.
So you see, there are plants that will be successful even in heavy, clay soil, you just have to pick the right ones.