Native Plants of Washington
From the time of the early explorers, plants native to Washington have been collected and introduced into cultivation, many of them being highly ornamental. Because the mild winters of the western part of the state are similar to those of the British Isles, one of the major gardening centers of the world, many native plants adapted easily to garden conditions. The drier summers of western Washington, however, mean that most plants are drought tolerant once established.
The best known tree is the Douglas fir, most often seen as scraggly individuals left from logging. When planted alone, with plenty of room, it makes a nice specimen tree, full and attractive. Other ornamental evergreens include red cedar and hemlock, both well-adapted to shade. The vine maple is a small tree with good fall color, and the magnificent form of the Pacific dogwood (Cornus nuttallii) can be found in disease-resistant hybrids such as 'Starlight." Madrona, an exceptionally beautiful evergreen tree with orange bark is difficult to transplant, but if you can find small plants grown in containers it is well worth the effort. Remember that it likes sandy or gravelly soil and little or no summer water.
Red flowering currant (Ribes sanguineum) is perhaps the most beautiful of the native shrubs with pink flowers in spring, though the native mock orange (Philadelphus lewisii) is a fragrant, drought-tolerant contender. For wet areas, consider the small bog rosemary (Andromeda polifolia) with gray-green, needle-like foliage and pink flowers similar to heather. Evergreen huckleberry (Vaccinium ovatum) should be used more widely for its shiny ornamental foliage, though the berries are a delicious bonus. The larger Pacific wax myrtle is also a fine foliage plant, useful for screens and hedges. Other native shrubs include Oregon grape, ninebark, red osier dogwood, and salad.
Ferns And Groundcovers
Both maidenhair fern and deer fern (Blechnum spicant) make excellent additions to a shady garden for delicate texture contrast. The larger sword fern is tough and will take more sun. For groundcovers, the native bleeding heart (Dicentra formosa,) twinflower (Linnaea borealis,) and wild ginger (Asarum caudatum) are choice ornamentals that would grace the most elegant garden. Others include Oxalis oregana, false Solomon's seal (Smilacena racemosa) and false lily of the valley (Maianthemum dilatatum.)
The large western white trillium (T. ovatum) is a prized wildflower and not difficult to grow. The camas (Camassia quamash) is also easy and usually available from bulb suppliers. You'll find Oregon iris (I. tenax) in the form of the Pacific Coast hybrids, excellent small plants for dry shade. Other perennials include blue and yellow eyed grass (Sisyrinchium idahoensis and californica,) Tiarella and goatsbeard (Aruncus dioica.)