The camellia is an evergreen flowering plant native to Asia and often cultivated as an ornamental shrub for gardens in milder climates. It is particularly popular in the Southeastern United States. While the camellia is a fairly robust plant, it can be afflicted by several diseases and insect pests. Common camellia diseases include flower and petal blight, canker and dieback, root rot, leaf gall and virus variegation. Some of these diseases can be successfully cured through chemical treatments and selective pruning.
Flower and petal blight is a serious camellia disease that affects the blooms of the plant. This blight is caused by a fungus that develops along the flowers, causing them to turn brown. Once mature, this fungus will release spores that may infect other plants in the area or different parts of the same plant. While opinions vary on the application of fungicides to cure this disease, many horticulture specialists recommend removing infected areas by hand, disposing of dead and diseased foliage and replacing the mulch around the bottom of the plant. The gardener also may wish to notify his neighbors of the disease so they can look for signs of this fungus and proceed accordingly.
Another of the serious camellia diseases is known as canker and dieback. This disease also is caused by a fungus, although this one damages the stems and bark of the plant rather than the blooms, and plants with this disease suffer from leaves turning yellow and wilting. Cankers form along the stems of the plant and may eventually kill the camellia if left untreated. The fungus thrives in heat and humid weather, making this disease a serious problem in the Southeastern U.S. Horticulturalists recommend pruning away infected regions and applying preventive fungicide during the spring.
Areas with poor soil conditions can leave a camellia vulnerable to root rot. This fungus can cause yellow leaves, retarded growth and, in serious cases, the death of the plant. The disease can be controlled by improving soil conditions and applying fungicides to the root areas, although this will not eliminate the fungus. The gardener may wish to consult with a landscaping company when considering treatment options.
Leaf gall is another of the fungal camellia diseases that usually affects new growth on the plant during the spring. The fungus may cause new leaves to become discolored or distended. While this disease can appear alarming to gardeners, leaf gall is generally considered a minor condition and will typically resolve itself after a few weeks. Removing and disposing of infected leaves may help prevent the recurrence of the disease in the future.
Although most serious camellia diseases are caused by species of fungi, the shrub also suffers from virus variegation. These viruses cannot be cured and may cause the discoloration of both leaves and flowers. The virus also can slow growth and weaken the plant’s resilience to drought and other diseases. Gardeners should buy plants from reputable sources and carefully inspect new purchases to help avoid this illness.