The flowering redbud tree, Cercis canadensis, can fall prey to disease and insect pests. Here is how to control them if they occur.
Diseases: Verticillium Wilt
Verticillium wilt attacks the eastern redbud tree through the soil. Watch for leaves that turn yellow and then brown. Prune dead growth, and water deeply at the roots 3 times a week. Use a nitrogen-based slow-release fertilizer monthly.
Rain carries this destructive fungus to the healthier tree parts. There is no cure, but spray a copper-based fungicide on the entire tree during and after heavy rains. Prune all lifeless branches. Disinfect shears with rubbing alcohol or Lysol after each cut.
Insect Pests: Spider Mites
Spider mites drink sap from the leaves, which become covered with yellow specks. During warm, dry weather, they can defoliate a tree. Use specialized miticide all over the leaves and at leaf crotches.
This tiny insect lives on the leaves and bark. Leaves turn yellow as they drain sap from the leaves and branches. Kill new eggs in spring with horticultural oil. Control the nymph larvae in summer with cabaryl.
A healthy redbud tree in clean soil does not tempt insect pests and disease. Water, fertilize and prune off dead branches to protect your redbud tree.