A few years back, I was asked to create a design for a site with soggy soil in winter and sunlight that shifted from full sun to shade. The challenge was to turn these obstacles - wet soggy soil and changing sunlight - into advantages. To make matters worse, the area was overgrown with weeds and had piles of yard waste from the previous homeowner. The area was so overgrown I could barely walk through it.
During my site evaluation, I found that there was quite a bit of natural compost from the surrounding trees, and from the yard waste as well. The yard waste was in small piles that were subsequently spread evenly around the entire space.
If your site has little or no compost, I recommend that you bring in at least 6 to 8 inches of compost and mix it into the top 12 inches of the existing soil. This is especially important if you have clay soil.
The biggest challenge was to clear the area. If this step seems insurmountable to you, divide the area into smaller spaces and completely clear out each area and move on. I prefer to do clearing work in early spring. It sure beats sweating on a hot day in July while you are also swatting flies and mosquitoes.
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The next step is a lot more fun - choosing the plants. But before I begin any design, I look at the existing structure. For this project, there were four majestic Western red cedar trees that dominated the landscape. The trees created areas of shifting light; there was full sun near the front of the trees and shade behind them.
In my mind's eye, it was essential that the new plants contribute to the woodland feel of the site. It also was an opportunity to build habitat for wildlife. And my client wanted access to the area and so identifying the location for a path also was important.
To maintain the woodland feel of the landscape, I designed perennials and grasses in large natural drifts of five to seven plants. In the shade of this garden, foliage and texture play the starring role, while flowers are secondary.
The shade portion of the garden is dominated by plants with bold leaves such as hosta and ferns. The large leaves of hosta are offset by contrasting feathery ferns and fine-leafed sedges. The flowers of Siberian iris, goatsbeard and primroses provide a splash of color in spring and early summer. The native shrubs - elderberry, ninebark, and osoberry - thrive in soggy soils and full sun. Their berries will attract birds and other wildlife.
Many delightful plants thrive in soggy winter soils. Do not think you are limited. Check out the list of my top twenty favorite plants for soggy soils. Plants marked with an asterisk (*) are Pacific Northwest natives.
Shrubs: Carolina allspice (Calycanthus), Twinberry (Lonicera)*, Osoberry (Oemleria)*, Pacific Ninebark (Physocarpus)*, Elderberry (Sambucus)*
Ferns: Lady Fern (Athyrium)*, Sword Fern (Polystichum)*, Christmas Fern (Polystichum), Ostrich Fern (Matteuccia), Wood Fern (Dryopteris)
Sedges and ornamental grasses: Sweet Flag (Acorus), Sedges* (Carex a few native species), Tufted Hair Grass (Deschampia most varieties), Feather Reed Grass (Calamagrostis), Bulrush* (Scirpus a few native species)
Perennials: Goatsbeard (Aruncus)*, Astilbe, Primroses (Primula most varieties), Siberian Iris , Hosta, Globe Flower (Trollis), Foxglove (Digitalis)
Author Mary Jo Buza is a landscape designer and owner of Gardens by Design. She has 25 years experience designing and teaching gardening in South Sound. For more information on a custom landscape design or consultation, call her at 360-923-1733 or go to www.gardendesignsbymaryjobuza.com.