Laura Heldreth explains her seven steps to creating a shady haven in the dry shade of mature trees. Laura is a Master Gardener in Vancouver, Washington, and this article is shared with her permission.
My oasis garden is located under a grove of mature Douglas fir trees. Whenever friends and students tease me about my ‘jungle’, I grin, because my ‘jungle’ is growing in dry shade and competing with thirsty tree roots. Let me take you through my steps on how to create a shady haven in dry shade.
Map out the light conditions in your garden because certain plants prefer different light conditions. Go outside on a clear day and observe how the light moves through your garden, each season of the year. You can sketch out a shade map or take pictures of your garden throughout the day to note how much direct sunlight your garden receives.
Shade: Full shade is less than two hours of sunlight a day.
Dappled Shade: Dappled shade is a garden site under a canopy of trees and this area receives about two to three hours of sunlight filtered through the branches above.
Open Shade: shade provided by a building, not a tree canopy.
Partial Shade: 2 to 4 hours of sun per day.
Partial Sun: 4 to 6 hours of sun per day.
Full Sun: Six or more hours of direct sunlight per day.
Your light map will change over time, so make sure to note changes when a neighbor removes a tree, there’s windstorm damage, or an arborist prunes your trees.
Make it a priority to protect your large trees’ roots. Large trees like the Douglas fir have most of their root systems in the top 12 to 24 inches of soil and spread out past the canopy’s edges or drip lines. So, plant small plants to prevent digging damage to your tree roots and maintain the current soil level.
Create an irrigation plan that will water the garden at least once a week during the summer drought. Large tree roots are competitive for moisture, especially during heat waves. Install a watering system using drip irrigation, soaker hoses, or sprinklers. Make sure to water deeply and check to make sure that the water is soaking in, not just running off the surface of the soil.
Add a two to three-inch layer of wood-based mulch to prevent weeds, hold in moisture, regulate soil temperature, and prevent soil run off. Leave a ring of bare soil that is 2 to 6 inches wide around the base of your trees and shrubs to keep them healthy.
Fertilize your shade garden plants with organic nitrogen meal fertilizers like alfalfa meal, feather meal and blood meal. Clark county soils are high in phosphate and potassium, but nitrogen is water-soluble and rinses out of the soil each season. Scratch in your organic nitrogen meal in early spring and water them in.
Research your plant choices before you head to the nursery. Great Plant Picks (www.greatplantpicks.org) has a comprehensive plant list that is compiled by horticultural experts in the Pacific Northwest. Their dry shade plant recommendations are fantastic. Plant Lust (www.plantlust.com) helps gardeners locate the plants they want through local growers in the Pacific Northwest.
If you’re looking for design inspiration, visit Darcy Daniel’s website eGardenGo (www.egardengo.com). Look through her suggested plant combinations and find helpful garden design tips and advice in her blog.
Take time to enjoy your garden. Whether you like to barbecue or meditate in your space, make time to do it. Your garden is for your use and pleasure.
Gardening with big trees takes extra planning and care, but is worth the effort. Your new shady haven can become an extension of your home, an entertaining space, and your private oasis.