· Gardenality.com's Answer
· Hi Bob,
Burning Bush can suffer from severe drought or too much rain fall. You mentioned the leaves curling up and turning brown. This sounds more like drought. When you water them once a week how thoroughly are you watering? Are you making sure to water enough to reach the entire root zone? This would involve using the trickle method. Turn the hose on and set it to a trickle of water flow. Place the hose at the base of the plant and allow it to soak in for 20-30 minutes or longer.
Has your area experienced unusually high amounts of rain fall? If so, and if you are also giving supplemental water, it could be too much water. This could cause root rot and leaves to turn brown. Usually if root rot occurs the leaves will turn brown at the tips first. Leaf spot is another symptom of root rot.
Spider mites are fairly common with burning bush. If spider mites are present discoloration, browning leaves, dead wood, and leaf drop will all occur. To check for spider mites hold a white sheet of paper under the foliage where it's brown and green.Tap the branches. If you see little specks moving around that are about the size of a pencil tip, either orange to red in color or greenish with two black spots, then your plant has spider mites. Control spider mites with Neem Oil. Neem oil is organic and very safe to use. And just in case the problem is a disease Neem Oil controls disease as well. Check both of your plants. Spider mites do travel from one plant to others.
Hope this helps you out.