Fall weather perfect for tree planting
The start of fall is a good time to consider the important contributions trees make to the environment — especially in urban neighborhoods like those found in Portland. Aside from the beautiful fall colors of deciduous trees, trees also provide clean air, clean water, wildlife habitat and, in many cases, higher property values.
The month of October marks a great time to plant new trees. Air temperatures are cooler than the soil, encouraging new root growth. Also, fall rains help trees and shrubs establish strong root systems.
Here are a few good tree choices — including nice shade trees — to consider planting this fall.
Trees for small gardens
Pacific dogwood (Cornus nuttallii)
This lovely native tree is naturally found growing as a shade tree in forested areas. Its deep green leaves are oval in shape and its large white petals – called "bracts" – are lovely and eye-catching.
Dogwood prefers well-drained acidic soils. Plant Pacific dogwood where its trunk will be shaded from sun; regularly rake leaves and remove them to help prevent anthracnose. This native tree is popular for its spring beauty and is used by sapsuckers, woodpeckers, white-crowned sparrows and many other birds for food and habitat.
Crape myrtle (Lagerstroemia)
This beautiful, fast-growing, small- to medium-sized flowering deciduous tree is cultivated in warmer climates the world over. Native to China and Korea, it has a long blooming period from mid-summer to fall.
It's commonly found growing in the southernmost portions of the U.S., including California, Nevada, Texas and Florida, but a wide range of cultivars — including "Muskogee," "Sioux" and "Natchez"— can be successfully grown in most parts of Oregon.
Crape myrtle is well-suited to urban gardens but needs plenty of summer heat to bloom well. Plant them in the hottest, brightest locations, and water deeply but infrequently. Avoid excessive watering, pruning, or fertilizing in the fall, and mulch heavily after leaf drop.
River birch (Betula nigra)
This tree has distinctive bark, grows to a height of about 50 to 60 feet, is heat-tolerant and makes a good shade tree. Leaves are glossy green and somewhat triangular. A popular and fast-growing ornamental tree, it likes full sun. The bark is attractive, exfoliating to reveal tan or pink coloring, which contrasts nicely with white-barked species if planted close by. It's usually resistant to bronze birch borer.
Norwegian sunset maple (Acer truncatum x A.platanoides 'Keithsform')
This maple features particularly nice branch structure and good yellow-orange to red fall color. It reaches an average of 35-feet in height with good resistance to heat and urban pollution. A fairly fast grower with an attractive uniform canopy and dark, glossy foliage, it likes full sunlight.
Lacebark elm (Ulmus parvifolia)
This is a graceful shade tree with a rounded crown and lustrous dark green leaves that turn yellow and reddish purple in the fall. Usually resistant to Dutch elm disease, it's a fairly fast-growing, tough and durable tree growing 40 to 50 feet in height with a 40-foot spread.
Appreciates twice-per-year nitrogen fertilizer (slow-release variety), likes full sun and adapts to many soil conditions. Although not a large tree, it can make an excellent windbreak.
For Large Yards
London planetree (Platanus x acerfolia)
These magnificent trees are excellent shade trees. Whether lining a touristy boulevard in London or Rome, or planted along a major Corvallis thoroughfare, they're popular for their abundant shade and attractive bark. Remember these large trees require adequate space for both roots and crown. Also, the "dust" they produce can trigger allergies. These trees are tolerant to heat, drought and pollution; their unique seed balls attract squirrels, finches, warblers and many other birds.
Bigleaf maple (Acer macrophyllum)
As the name implies, Bigleaf maple has the largest leaves of any maple. An Oregon native, it makes a great shade tree but requires lots of room — most can reach a height of 50 feet or more. Grows in full sun or partial shade and attracts small mammals like chipmunks, and songbirds.
Plant this tree only if you have a very large yard with plenty of room. Protect bark from injury while young; you'll be rewarded with a little fall color and nice summer shade.
Willamette Valley ponderosa pine (Pinus ponderosa var. Willamettensis)
This attractive large evergreen tree — genetically distinct from Ponderosa pine found east of the Cascade Mountains — is easy to grow and can reach 150 feet or more in height. Its deep green needles, in bundles of three, are 6" to 10" long. The Lewis's woodpecker and slender-billed nuthatch rely on it for food.
Plant in a location with lots of room as these trees get large, and remember to weed the young tree regularly its first three years. Willamette Valley pine prefers well-drained soils and is highly drought-resistant. It bears handsome large brown cones and exudes the pleasant scent of vanilla.
For the Birds
With winter approaching here's a few quick tips for helping the birds. Plant a variety of shrubs — like snowberry, twin berry or serviceberry — as this is a good way to provide fruit for birds throughout the seasons. Also, don't deadhead your flowers, but let seeds remain on the plants through the fall and winter for goldfinches and other seed-eaters.
Bird feeders filled with black oil sunflower seeds are the best for attracting songbirds. Keep a birdbath filled with fresh, unfrozen water.
Find time to help the birds, plant a new tree in your yard or look for fun tree-planting volunteer opportunities, and enjoy this special time of year.
Cynthia Orlando is a former forester and arborist; she recently retired from the Oregon Department of Forestry.