Alabama Tree & Shrub Care: Identifying Pests and Diseases

Ornamental trees and shrubs are not only beautiful additions to your lawn and landscape, but they also boost curb appeal. However, they are vulnerable to various pests and diseases. With Alabama being generally warm and humid, many common pests and diseases can pose a threat to your trees and shrubs. Homeowners handling summer tree care should know how to spot pests and diseases and what to do next.

Common Signs of Trouble for Alabama Trees and Shrubs 

A crucial part of tree and shrub care is monitoring the health and conditions of your plants year-round. Knowing what signs are cause for concern for common Alabama plants can be the difference in preventing your landscape plants from dying.

Dogwood Trees

Dogwood trees are known for their stunning spring blooms and vibrant foliage, making them a popular choice in Alabama landscapes. However, they are vulnerable to pests and diseases that can affect their health and beauty.

Dogwood Blotch Miner is a common insect that can cause damage to a dogwood tree. They are small, translucent maggots that tunnel in the leaves of dogwood trees, creating “mines” as they feed. Yellowing leaves and brown blotches of discoloration are common signs of infestation. Pruning and disposing of infested leaves, along with proper watering and fertilization, is best for pest control.

Azalea Bushes

Azalea bushes are another popular choice for Alabama gardens due to their bright colors in the summertime. Depending on the species, azaleas commonly bloom anytime through early to late spring, with some blooming in late winter around February. With beautiful florals that add to any landscape, it’s important to know how to protect azalea bushes from common insects such as lace bugs.

Azalea Lace Bugs are small, winged insects that feed on the undersides of leaves, causing stippling, yellowing, and leaf drop. Regular monitoring, shrub care, and targeted insecticide application can control lace bug infestations.

Magnolia Trees

Magnolia trees are a very common favorite and the University of Alabama is actually home to one of the largest magnolia trees in the state. The Alabama Forestry Commission recognized the Southern Magnolia as the current largest of its species in Alabama, naming it an Alabama Champion Tree. Magnolias are cherished for their beauty and fragrant flowers. However, they can face various threats through the growing season.

Magnolia Scale is an insect that secretes honeydew, leading to new growth of black sooty mold and weakening the tree. Homeowners should prune infected branches and apply horticultural oils to help control scale insects.

Crepe Myrtles

Crepe myrtles are a great addition to any landscape in the southeast due to their vibrant blossoms, attractive bark, and heat tolerance. Summertime is the best time to plant Crepe Myrtles as the young trees will benefit from warm soil. While these trees are both heat and drought-tolerant, they can be vulnerable to various insects and diseases.

Aphids are small insects that feed on crepe myrtle leaves, causing curling, distortion, and the growth of black sooty mold. At the end of each growing season, females lay eggs that survive winter months and hatch in early spring. Ladybugs are natural predators in controlling aphids, and homeowners can assist by washing them away through watering as well.

Boxwoods

Boxwoods are widely cherished for their dense foliage and versatility in landscaping. Boxwoods have shallow root systems and improper fertilization can cause damage to the plant. Boxwoods are susceptible to common insects like mites, and diseases like Boxwood Blight. With the right care and knowledge, Boxwoods can be a beautiful, healthy addition to your Alabama landscaping.

Boxwood Blight is a disease that causes leaf spots, defoliation, and lesions on stems. Removing and destroying infected parts of the plant is crucial in preventing its spread. Fungicides cannot cure blight-damaged plants but can be used to protect new or existing foliage.

Nandina

Nandina, commonly known as heavenly bamboo, is cherished for its vibrant foliage. It’s important to research which cultivars are safest for landscaping, as Nandina produces berries that can be toxic to some wildlife. It’s recommended to use cultivars that produce little to no fruit. While generally hardy, it can face various disease challenges.

Powdery Mildew: This disease looks like a white powdery coating on the leaves, leading to decline and leaf drop. Adequate spacing, proper airflow, and avoiding overhead watering can mitigate powdery mildew.