Shrubs
Frequently Asked Questions

  1. The leaves on my azaleas have tiny white spots on the upper leaf surface and black or brown spots on the lower leaf surface. What is wrong with my azalea?
  2. A lot of buds are dropping from my hibiscus. What could be causing this problem?

1. The leaves on my azaleas have tiny white spots on the upper leaf surface and black or brown spots on the lower leaf surface. What is wrong with my azalea?

Azalea leaf with signs of lacebug damageThis is typical of damage caused by the azalea lace bug. The little white spots or stipules are places in the leaf where the chlorophyll has been removed by lace bug feeding. They feed from the underside of the leaf and leave shiny black spots of fecal material that eventually turn brown.

Feeding by mites also leaves a stippled effect on the upper leaf surface, there will be no shiny black or brown spots on the bottom side of the leaf. Webbing is also associated with the presence of mites on the underside of leaves.

lace bugs feeding on azalea leafLace bugs can be controlled with sprays of horticultural oil (Ultrafine oil), or chemical sprays such as Sevin, diazinon, Cygon or Orthene. The systemic product imidacloprid (Bayer Advanced Shrub and Tree Insect Killer) also will control these pests. Make 2 applications at a 10 day interval with all products except imidacloprid in which one application should be sufficient.

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2. A lot of buds are dropping from my hibiscus. What could be causing this problem?

Premature bud drop is often a problem with hibiscus. Some varieties, especially some doubles, are characterized by premature bud drop. Some varieties bloom well during one period of the year and consistently drop their buds at other times. Bud drop can also be caused by insects such as thrips and caterpillars. Nematodes, nutritional deficiencies, over-fertilization, and environmental factors such as poor drainage and excessive water, drought, or salt spray can cause flower buds to drop.

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