State Highways Tree List

The Maryland State Highway Administration is in the process of planting nearly 16,000 trees along the thoroughfares throughout Frederick County. Seventy five different tree and shrub varieties have been identified for planting on nearly 70 acres as part of this program.

The intent of these plantings is to enhance water quality through the uptake of nutrients, sediment and other pollutants before they can reach the water, to hold soil in place to reduce erosion, and to soak up excess water after it rains. These plantings will also reduce traffic noise, provide an aesthetic screen, and impress with springtime blooms and fall coloration. The treed canopy will also help cool the area during the hot, hazy days of summer.

This wide variety of trees chosen provides landscape designers with a diverse palate of plants to accentuate the surrounding landscape. Where large trees are acceptable, and the conditions are somewhat dry, majestic varieties such as tulip poplar, northern red oak and white oak can be planted.

Large growing varieties like pin, swamp white and willow oaks, sycamore, and river birch can be planted in the lower areas that remain a bit damper. There are trees on hand such as sumac, serviceberry, black gum, and redbud that can tolerate poorer soils and dry conditions. Then there are varieties like red maple and black gum that are tolerant of a wide variety of conditions that can be planted all over. Best of all, the maple and gum have brilliant fall coloration.

Many different cultivars of red maple have been developed over the years that display differing sizes at maturity, fall coloration, growth habits and insect and disease resistance. Cultivars of red maple have even been developed that display their fall colors at different times during the autumn so as to stagger color displays.

These highway plantings are incorporating four separate varieties of red maple and three distinct cultivars of sugar maple. The sugar maple grows best on shadier locations that are a bit cooler and are not bathed in sunshine throughout the day. Trees like hackberry, elm, redbud and cedar are good choices in limestone soils like those that are found around Md. 194 between Walkersville and Woodsboro.

The varieties of elm chosen have been cultivated to display resistance to Dutch elm disease. Evergreen varieties such holly, cedar, and white pine can create a year round screen and provide shelter for animals during the winter. Most of these evergreens do better in acid soils, with the cedar tree being a notable exception.

Trees such as flowering dogwood, serviceberry, sweet bay magnolia, cherry, yellowwood, redbud, and fringe tree produce a showy bloom during the spring. These smaller varieties will intermix with the larger trees, and they will also be planted closer to the roadway where they will be more visible to passing motorists. Most of the trees chosen have beautiful fall colors especially the maple, black gum, hornbeam, sweet gum, yellow wood, sassafras, and sumac.

The wide variety of trees and shrubs chosen for these roadside tree plantings will provide a lot of visual diversity along the roadways. Having this diversity will lessen the chances that significant insect or disease infestations will impact these plantings compared to efforts that select a limited variety, thereby creating a monoculture.

Having this diversity will also lengthen the spring flowering and fall color displays as many diverse plants get their chance to show off. The inherent diversity will also make these plantations more wildlife friendly, particularly to birds. Best of all, the trees chosen are native species that you might find growing in your local woodlot!

Nature Notes for 2/22/2015