Many landscapes are taking a beating with the summer’s hot, dry and humid trend. In a neighborhood close to the garden center, a maple tree has already changed to the red fall color not usually seen until early October; there are other non-native trees in parts of Appleton also changing early. Native plants, however, seem to handle bad years like this one in stride. Many people who grow native plants believe this is due to the fact that native plants are used to our growing season: bitterly cold winters with snow and ice, and hot and humid summers.
A beautiful ornamental tree that is also native to parts of Wisconsin is Pagoda Dogwood, or Cornus alternifolia. The tree reaches about 15-20 feet in height and 10-15 feet in width. White flowers bloom in early June, and berries can be seen in late summer if the birds don’t eat them before they have a chance to get ripe. The green leaves turn a dark maroon-purple in fall. Perhaps the most distinguishing characteristic is the way the branches form horizontal tiers. It does best planted under existing trees, or in a partially shaded area where it gets a half day of sun and shade.
Another shorter tree that is a Wisconsin native is a mountain ash, or Sorbus. It grows to about 25-30 feet tall and usually only about 15-20 feet wide. In spring, white flower clusters bloom, which form bright orange or red berries in summer. If the birds don’t eat the berries before winter, they will certainly eat them in late winter or early spring when they come back north. Robins especially flock to these trees in March and April. The compound leaf means it will give dappled shade. The bark is a brown-copper color with white streaks throughout. This ash is not a true ash, which means the emerald ash borer does not attack it. Although EAB has not been found in the Appleton area yet, you can rest assured this tree will not be affected by its appearance.
Wisconsin’s state tree is well known, especially in fall. Sugar maple trees prefer sandy soils, but new varieties have been bred to better withstand urban environments, including clay soil. Full grown, these trees can be quite large, growing to 50 feet tall and 40-50 feet wide. The green leaves provide a dense shade in the summer, but is often many peoples’ favorite tree in fall when the orange and yellow tones burst in the landscape.
Swamp White Oak gets its name because it is native to moist or swampy areas in Wisconsin. However, it makes a wonderful urban tree because it tolerates all soil types and withstands drought well. It is a slower growing tree, but deserves a second look because it has some unusual characteristics. The bark and branches become flaky and mottled as it ages, which makes this tree a good substitute for another Wisconsin native, the river birch. The green leaves are heavily lobed and don’t have much fall color, but the leaves stay on the tree all winter and into early spring. Acorns start forming on the tree once it gets older as well. Once mature, expect it to reach about 50-70 feet in height and about the same width.
An evergreen native to our soils here is White Spruce. However, they don’t do as well in urban conditions: pollution, clay soil, or compact root systems. A good substitute, while not a native tree but one that grows wild in the northern forests in Wisconsin, is Norway spruce. Norway spruce is a bold green color and has a nice pyramidal shape as a young tree. Once it’s mature, however, the branches tend to become pendulous and hang like moss. It is tolerant to all soil types and can grow up as a young tree in some shade, since that is its native habit. It often gets to be about 40-60 feet in height, with a spread of about20-30 feet. Hostas, ferns and many spring wildflowers do quite well when planted underneath the canopy of this evergreen tree.
Stop in to the garden center to find many native trees like the ones listed above. Garden center hours are Monday through Saturday, 8-6, and Sunday from 10-4.