Brown Leaves on Rhododendron

Rhododendrons are flowering shrubs that produce bright, showy flowers. They grow best in mild, humid weather. Because rhododendrons are evergreen, browning leaves indicate a problem with the plant.

Winter burn causes rhododendron leaves to turn brown and eventually fall off. Frozen soil keeps roots from absorbing water and cold winds that dry leaves. Winter burn can be prevented by planting your rhododendron in mulch and making sure it has plenty of water before the winter sets in.

Root rot is a disease caused by fungi such as pythlum and botryosphaeria, both of which result in root decay in rhododendrons. One major symptom of root rot is browning leaves that eventually fall off. To prevent root rot, make sure your rhododendron is planted in well-drained soil.

Rhododendron leaf spot is a disease that produces small to large brown spots on rhododendron leaves. The spots grow into each other and make the whole leaf appear brown. Leaf spot can be caused by a number of reasons, including chemical burns, fungi and viral infections. Treatment depends on the ailment.