Drought tolerance

The weather forecast yesterday said “showers” but I only saw a couple of half-hearted spatters, not even worth putting on a hat. Someone told me Tuesday they’d had enough of the dryness.  “Bring on the rain!” he said.  Spoken like a true native!  Sounds like his tolerance to drought has reached its limit.

Drought-tolerant plants are being put through their paces right now. The bit of rain we got last night hardly even counts.  Our summers (and it is still technically summer) are very dry, despite western Washington’s reputation for rain.  Our native plants are adapted to our wet winters and dry summers.  Most of our natives, unless they are strictly wetland plants, are drought-tolerant to a certain extent, but as for those that thrive in the most exposed locations, with very well-drained sandy soils, the selection is much smaller.  Among those are three shrubs:  Mock Orange (Philadelphus lewisii), Ocean Spray (Holodiscus discolor) and Tall Oregon Grape (Mahonia aquifolium).

Mock Orange (Philadelphus lewisii) is a deciduous shrub with fantastic-smelling white mid-summer flowers. Swallowtails and other butterflies appreciate the flowers’ nectar and birds eat the seeds.  It grows quickly, and grows fairly wide, getting up to10 feet tall. Its vigorous root system will help stabilize soil on a slope.

Ocean Spray (Holodiscus discolor) is also deciduous, with interesting scalloped leaves, twiggy branches that provide excellent cover for songbirds, and striking cream-colored flower clusters.  They bloom in late May and June (perfect timing to be used for a bridal bouquet) and the hundreds of tiny flowers that make up each graceful, drooping oblong cluster attract many tiny pollinators and other insects.  The seed clusters remain throughout the winter, another factor good for bird habitat.  Ocean Spray gets up to15 feet tall and nearly as wide.  It does just fine where it is subjected to salt spray (like its name).

Tall Oregon Grape (Mahonia aquifolium) also does well by salt water.  Its attractive, shiny evergreen leaves are prickly like holly.  New growth is bronzey-colored.  Yellow flowers in early spring provide nectar to bees, butterflies and hummingbirds and the pretty blue berry clusters feed a variety of birds, small mammals and large mammals, including Homo sapiens and Sasquatch. Its vertical stems max out at 6 to 8 feet tall.  It is rhizomatous, so will slowly spread to form a patch. This gives it good soil-holding capacity, even on Puget Sound bluffs.  Tall Oregon Grape is Oregon’s state flower!

All three of these will do well in harsh, exposed conditions with hot sun and fast-draining soil, once their roots have a few seasons to grow deep for moisture. They don’t require those conditions, however, and will do fine with some moisture in the soil or in partial shade.  The three combined would make for a beautiful, bird-friendly hedgerow.

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