CORVALLIS, Ore. - Northwest gardeners are blessed with many evergreen plants that keep the landscape looking alive all year. Even so, a vibrant splash of color in the garden can ease the loss of summer.
Perennials, especially asters and chrysanthemums, may be the most familiar plants for fall garden color. There are also trees and shrubs that can brighten up your surroundings when summer's over, some of them familiar and some unusual.
You can plan ahead and look in books or catalogs to learn which kinds of plants you want and where you want it to be in the color spectrum. Even so, it is always a good idea to see the actual variety of tree or shrub in the area you live turn fall color before you buy it, advised Linda McMahan, horticulturist with the Oregon State University Extension Service. Autumn is the time to do that.
Fall foliage color varies even within a species, from place to place. Trees that may be brilliant in California in September, may be much less so in Oregon, McMahan said. If your heart is set on crimson, you don't want to find out later that the tree you bought turns yellow-beige where you live.
Maples are known for fall color from New England to the West Coast. There are many cultivars of red maple (Acer rubrum) that provide showy fall color. These are fairly fast-growing and large trees, with heights up to 60 feet. To see photos of several species of maple in Oregon landscapes, visit OSU's Landscape Plants website.
Vine maple (Acer circinatum) is native along the Pacific Coast from British Columbia to northern California. It's a relatively small tree, somewhat shrubby in form. In shady areas, it tends to a vine-like but graceful sprawl. In a sunny open spot it can become heavily leaved and symmetrical. Its fall colors lean toward yellow in the shade and crimson in the sun. However, it's essentially a shade-loving tree and may need extra water if it's planted in the sun. To see a photo of vine maple in a western Oregon home landscape, see http://oregonstate.edu/dept/ldplants/acci7.htm.
A popular and successful tree for fall color in the Willamette Valley is the sweetgum (Liquidambar). Because their leaves are similar, sweetgums are often mistaken for maples, but the spiny balls that hang on them in the winter – and often clutter the ground around them – make identification quick and easy. Their brilliant fall color varies from red to gold to purple. A specific variety can vary in color from one area to another and even in one tree from year to year. The surest bet is to buy your tree in the fall when it's actually in color. For a photo of sweetgum in the fall, see: http://oregonstate.edu/dept/ldplants/list13.htm.
"A good alternative to sweetgum, which tends to be messy, is the katsura tree (Cercidiphyllum japonicum) and its shrub 'look-alike, redbud hazel' Disanthus cerdifolius," said McMahan. "It can have yellow, red and deep purple leaves all at the same time."
There's a good photograph of a katsura tree at http://www.ubcbotanicalgarden.org/potd/disanthus_cercidifolius.jpg. Katsuras are native to China and Japan. They do best in a sheltered spot and with regular water.
Sitka mountain ash (Sorbus sitchensis) is native along the Pacific Coast from northern California to Alaska. A small deciduous tree with finely toothed leaflets, it fits easily into many garden settings. In the late summer and fall it bears a profuse crop of bright orange to scarlet berries which attract birds by the score. Its foliage also turns orange to orange-red.
Western mountain ash (Sorbus scopulina) is similar and native further inland.
For something entirely out of the ordinary, McMahan suggests, consider witch hazel (Hamamelis), which grows to the size of a large shrub or small tree. Japan, China and North America all have native species of witch hazel. All have an irregular branching form and bright fall foliage. Most have distinctive spidery yellow flowers in the fall to winter, some of them mildly fragrant.
Or, check out the witch hazel's relatives, Fothergilla major and F. minor, with their brilliantly red fall leaves and fragrant white spring flowers. These are a little harder to find but definitely worth the trouble, she said. You can see a color photograph of their fall foliage on the web.
In addition to foliage and flowers, there's also colorful bark. Red twig dogwood, also called red-osier dogwood, (Cornus sericia) is a fast-growing deciduous shrub that forms clusters of up-reaching stems. It has bright red fall foliage. Once its leaves have fallen, the reddish stems provide subtle color throughout the winter. Redtwig dogwood is native along the Pacific Coast from northern California to Alaska. Yellowtwig dogwood (Cornus stolonifera coloradensis flaviramea), is a similar shrub with yellow bark. It is non-native, but has similar growing conditions. Photos of this genus, are at: http://oregonstate.edu/dept/ldplants/1plants.htm#cornus.