AMES, Iowa — An excellent way to brighten the winter landscape is to plant trees and shrubs that possess ornamental characteristics, such as colorful fruit or exfoliating bark. Horticulturists with Iowa State University Extension and Outreach describe shrubs and trees that add color to the winter landscape. To have additional questions answered, contact Hortline at 515-294-3108 or firstname.lastname@example.org.
One of the most beautiful sights in winter is the bright red twigs of the redosier dogwood (Cornus sericea) set against a backdrop of newly fallen snow. Native to Iowa, the redosier dogwood grows 6 to 10 feet tall. Several colorful cultivars are available. ‘Cardinal’ has bright, cherry red stems. ‘Alleman’s Compact’ is a red-stemmed, compact cultivar that grows 4 to 5 feet tall. Arctic Fire™ is a red-stemmed, 3- to 4-foot-tall shrub. ‘Flaviramea’ is a 5- to 6-foot-tall shrub with yellow stems.
There are also several cultivars of willow that possess colorful bark. The ‘Flame’ willow (Salix ‘Flame’) has reddish orange stems. The stems of the coral bark willow (Salix alba ‘Britzensis’) vary from yellow-orange to orange-red.
The redosier dogwood and willows should be pruned on a frequent basis as young shoots possess the brightest colors. ‘Flame’ and coral bark willows should be pruned annually. Cut back plants to near ground level in late winter. The redosier dogwood requires less pruning. In late winter, remove approximately one-third of the oldest stems near ground level.
Selecting trees with attractive bark is an excellent way to add interest to the winter landscape.
A widely planted tree that possesses attractive, exfoliating bark is the river birch (Betula nigra). The exfoliating bark varies from salmon-white to reddish brown. Often planted as a multi-stemmed specimen or clump, the river birch may eventually reach a height of 50 to 60 feet.
Two small ornamental trees with exfoliating bark are the paperbark maple (Acer griseum) and Amur chokecherry (Prunus maackii). The paperbark maple grows 20 to 30 feet tall, possesses cinnamon to reddish brown exfoliating bark, and is hardy in USDA Hardiness Zones 5 to 8. The bark characteristics of the Amur chokecherry are highly variable. Bark color varies from brownish yellow to reddish brown to cinnamon red. Some exhibit little or no bark exfoliation, while others exfoliate heavily. The Amur chokecherry grows 30 to 35 feet tall.
Other trees with showy bark include the lacebark pine (Pinus bungeana) and Chinese or lacebark elm (Ulmus parvifolia). The bark of both trees exfoliates in patches revealing a kaleidoscope of colors. The multi-colored bark of the lacebark pine contains splashes of green, white, brown and purple, while the Chinese elm is spotted with brown, gray, green and orange.
While crabapples (Malus spp.) are usually planted for their flowers, many cultivars also possess colorful, persistent fruit. Crabapple cultivars with red fruit include ‘David,’ ‘Donald Wyman,’ ‘Mary Potter,’ Red Jewel™ and Sugar Tyme®. ‘Indian Magic,’ ‘Professor Sprenger’ and ‘Snowdrift’ have reddish orange fruit, while Harvest Gold® and Golden Raindrops® are yellow-fruited crabapple cultivars.
Hawthorns (Crataegus spp.) are another group of small, flowering trees that possess attractive fruit. Hawthorns produce white flowers in spring. In fall, their small (one-fourth to one-half inch in diameter) fruit turn red and persist into winter. Two hawthorns noted for their excellent fruit displays are the Washington hawthorn (Crataegus phaenopyrum) and ‘Winter King’ hawthorn (Crataegus viridis ‘Winter King’).
Shrubs that possess attractive fruit in late fall and winter include red chokeberry (Aronia arbutifolia), cranberry cotoneaster (Cotoneaster apiculatus), winterberry (Ilex verticillata), Meserve hybrid hollies (Ilex x meserveae) and American cranberrybush viburnum (Viburnum trilobum). All of the aforementioned shrubs have red fruit. Snowberries and coralberries (Symphoricarpos spp.) have white, pink or purplish red fruit.
The brightly colored fruit of most of the aforementioned trees and shrubs do not remain throughout winter. Very cold temperatures in winter eventually cause many fruit to turn reddish brown or black. Hungry birds and squirrels may also devour the fruit. However, the fruit display in late fall and early winter can be spectacular.
The 2014 Iowa State University Extension and Outreach garden calendar celebrates the wonderful gifts that trees provide for other living things. In addition to striking photos, find monthly garden tips, tree-planting instructions, Iowa's state forests, vignettes of historical trees and quotes that trees inspired.
The 2014 garden calendar can be purchased at the Extension Online Store https://store.extension.iastate.edu/.