Drought-stricken plants are coming into our plant clinics in large numbers. Usually the owner says something like, “But the tree (or shrub or plant) has been there for years, and I have never given it much water.” Last summer’s heat and low rainfall coupled with our dry spell this spring has stressed many plants.
We have even seen large native trees affected. Some big-leaf maples and vine maples look scorched or are dying. Western red cedars are doing what we call flagging, when certain branches turn rusty red and die. Hemlocks and Douglas firs are losing older needles; sometimes whole branches or the top several feet will suddenly die.
Because these plants evolved in our area, where summers are commonly dry, I suspect that the groundwater level has dropped in some areas, compounding the added stress of more heat than usual.
Plants may wilt, roll up their leaves, die along the leaf tips and edges, yellow or suddenly turn brown. If you have a plant looking a little sad, get out and water it.
Don’t sprinkle; give it a thorough soak. Soaker hoses work well, or turn a hose on very low and leave it running for at least a half hour at the base of the plant. An hour after you water, take a shovel out and see if the water went all the way through the root zone.
I frequently see gardens that have been recently watered where the top inch or two of soil is damp, but the underlying soil (where the roots are) is dusty dry. This just encourages plants to grow roots at the surface, making them even more susceptible to drought.
Summer color
Is your garden a one-season wonder? Lots of us have yards that are lovely in the spring, but pretty boring by summer. I wrote about annuals in June and they are one solution. Another is to use plants with interesting colors and textures in the leaves and fruit. If you want flowers, but don’t want to replant every year, plant perennials that bloom in the summer.
White and pink Japanese anemones are favorites of mine. This plant is very invasive, so put it where you can control it.
Asters are a fall classic. True asters, such as Michaelmas daisies, come in every shade of pink and purple as well as white. Stokes asters have larger flowers that make great cut flowers.
Since I am crazy about blue flowers, I have lots of campanulas or bellflowers. Some, like the harebells and peach-leafed bellflower, are in full bloom now and will continue blooming sporadically all summer. Shearing back the Dalmatian bellflower, when it finishes blooming about midsummer, usually produces a fall re-bloom.
Dwarf plumbago, a low ground cover, has one of the most intense blue flowers you can imagine. They contrast nicely with the foliage, which turns reddish in the fall.
Globe thistles are big, bold plants with steely blue balls of flowers that go from midsummer through first frost. They tolerate drought well when established, a definite plus.
Shasta daisies, particularly some of the named cultivars like Esther Read, have long-lasting summer flowers. Chrysanthemums vary amazingly in color, size and flower form, but all bloom in summer or fall.
If you like warm colors, plant gaillardia (blanket flowers) and rudbeckia, also called gloriosa daisies. Both come in yellows, oranges and russet reds, often banded with multiple colors. These are good choices for a drought-tolerant planting.
Phlox add a big splash of color in summer. Be sure to look for cultivars resistant to powdery mildew.
The pink or rose, summer flowers of Sedum spectabile slowly turn a mahogany brown in autumn. With its blue-green, fleshy leaves, this is a winner for long-lasting interest.
Holly Kennell is the Snohomish County extension agent for Washington State University Cooperative Extension. Master gardeners are available to answer questions on weekdays at WSU Cooperative Extension Snohomish County, 600 128th St. SE, Everett, WA 98208. Call 425-338-2400.
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