Camellia shrubs or bushes have dark green foliage and beautiful blossoms in various colors that appear late in the year and can thrive well into the winter months in some areas. It is an evergreen with a cold hardy zone from six to 10, depending on the species. Originating in both south and east Asia, the Camellia has become a popular bush found in American yards. Easy to grow and care for, however the Camellia does have a few diseases you should watch out for.
Algae Leaf Spot
Symptoms include almost round blotches appearing on leaves. Raised edges of varying colors including silver, green, purple, brown, red and tan form on the leaves. Causes of this disease are bad soil drainage, high temperatures, improper nutrients and full sun. Prevention and control recommendations do not include fungicides, but do suggest pruning Camellia bush to eliminate diseased sections and to enhance air circulation around plant. Modify soil conditions with proper fertilizer cultivated into soil around Camellia shrub.
Brown Blight, Grey Blight
Symptoms include tiny, light yellowish-green, egg-shaped spots become visible on leaves that could have thin, yellow region around it. Infected area enlarges, changes to gray or brown, concentric circles appear with tiny black spots spread around and lead to leaves dropping off Camellia bush. Causes include poor air circulation, long periods of damp leaves and high humidity. Control and prevention recommendations include pruning and proper plant spacing to increase air circulation around Camellia bush.
Twig Dieback, Stem Canker
This serious disease is capable of killing entire Camellia plant. Symptoms of it include new leaf growth suddenly wilts, turns brown and then falls off. Cankers (gradual spreading lesions) often appear on diseased branches. This disease is quickly spread with water and from cut branches left lying around the area. Control and prevention suggestions include pruning six inches underneath the diseased part of plant, removing cuttings from growing area and disinfecting all tools used. Chemical control can be used at beginning of season in areas with earlier problems.
Blossoming flowers on the Camellia bush will begin to have light tan spots on petals that continue to grow until complete flower is brown. Infected petals falling to the ground infect the soil around the plant and reappear in the next growing season. Prevention measures include removing diseased blooms from plant and replanting Camellia in a sterile growth area. Management of infected bushes using chemicals spray in the area below the Camellia at first sign of new blooms, clearing region below plant and pruning bush for better air circulation.
Camellia bushes with this disease caused from many varying types of fungi will have a large amount of dead feeder roots. Left untreated, the fungus spreads destroying more of the feeder roots, causes the Camellia to wilt and eventually die. Prevention control is needed for this type of disease, since by the time you notice it on your Camellia bushes it is hard to alter. Do not over water plant, remove standing water and use well draining soil.