Avoid using troublesome plants
By Tim Daly
Gwinnett County Extension Agent
Fall and winter are the best times of the year to install new plant material. Though the weather is cold, the roots continue to grow.
The plants become established, and they can withstand the summer temperatures and dry conditions better. Some plants are troublesome in the landscape and should not be used. They may be prone to certain pests, have a weak growth pattern, or are messy. By knowing which plants perform poorly in the landscape, you can avoid planting them.
For many years, the red tip photinia was commonly planted in landscapes throughout the region. The new foliage is an attractive red color, and the plants make excellent screens for privacy. Unfortunately, red tip photinias are susceptible to a fungal leaf spot disease. Typically these leaf spot diseases do not kill the plant; however, the disease that infects red tips has been an exception. If you plant them, you risk the disease attacking and killing the plants. Consider alternative plants that are resistant to this disease and have excellent screening abilities such as various species of hollies, wax myrtles, and wax leaf ligustrums.
Several species of euonymus, mainly gold dust and Manhattan euonymus, are susceptible to scale insects and powdery mildew. Scale insects are white in color and form a hard, protective shell on their outside as they feed on the plant. Over time, their activity causes the leaves to drop, and branches to die. Powdery mildew is a fungus that causes a white substance to form on the leaves and branches. The disease can distort the leaves and cause them to drop. Pesticides can be used for controlling these problems; however, the best course of action is not to install these plants in the first place. Instead of euonymus, use other plants with similar qualities that have minimal pest problems such as Japanese hollies, carissa hollies, inkberries, and Indian hawthorns.
Bradford pears have been planted extensively over the past few decades. They have beautiful white blossoms in the spring and red to purple leaf color in the fall. Despite their attractive features, Bradford pears are structurally weak. They grow rapidly and have soft wood. The branches form a narrow-angle to the trunk causing the crotch to weaken. As the tree grows, the limbs become too heavy and break off, frequently damaging property. Instead of Bradford pears, consider planting other flowering trees that do not have these problems such as fringe trees, crape myrtles, redbuds, and certain varieties of crabapples.
Some trees are attractive in appearance and thrive in the landscape, but have a tendency to be messy in that they drop copious amounts of leaves, branches and sometimes fruit. River birches continually shed their leaves and branches over the growing season. Southern magnolias drop their large, leathery leaves and their seed cones. Sycamores consistently drop their large leaves. Prolonged dry spells make the problem considerably worse. Take into consideration the planting site. Messy trees should be located in out of the way places or in natural areas. Avoid installing them near sidewalks, driveways, patios, and swimming pools. Otherwise, you will be continually removing the debris.
Many beautiful trees and shrubs thrive in our area, and now is the best time to plant them. However, take into consideration any drawbacks that some have. By doing so, you can avoid plants in your landscape that are by their nature troublesome.
Timothy Daly, is an Agricultural and Natural Resource Extension Agent with Gwinnett County. He can be contacted at 678-377-4010 or firstname.lastname@example.org