By Bonnie L. Grant
Camellias are glorious early spring-blooming shrubs that thrive in shade to part shade areas. The plants are quite hardy and can withstand a variety of soils and sites. Camellia plant problems may range from fungal and bacterial, to insect and animal damage. Foliar damage is the most common problem with camellias and generally shows up as fungal spots or a sooty coating on the leaves.
Getting knowledge on how to fix sooty mold on camellia must begin with learning the causes of the black leaf coating.
Camellias can get up to 20 feet tall but are more commonly around 12 feet. The bushes prefer slightly acidic soil with moderate moisture in lower light situations. The glossy pointed leaves are an attractive foil for the old-fashioned, huge and many petaled flowers. The colors of the blooms may be white, pink or salmon, with some approaching red. Camellia plant problems may be cultural or caused by external issues such as pests or weather.
Camellia Plant Problems
Camellia plants are tolerant of a wide range of conditions, but they do need supplemental water and some protection from strong winds. Poor drainage can adversely affect the health of the plant, as can bright reflected sunlight, which will sunburn tender buds and new leaves.
The most common pests of camellias are aphids and scale. These sucking insects produce a secretion, called honeydew, which causes camellia sooty mold. It is common to see a camellia with black leaves in summer and into fall. The coated leaves will eventually drop and the loss of photosynthetic surface will reduce the amount of plant sugars the bush can make to feed itself. This in turn causes reduced growth and vigor.
How to Fix Sooty Mold on Camellias
The black fungal growth on the leaves of camellias and other plants is a form of fungus that feeds off the honeydew. The honeydew is a byproduct of the sucking insects’ feeding and is nourishment for the fungal spores. A camellia with black leaves is coated with a suffocating substance that prevents respiration and minimizes the ability to collect solar energy.
Camellia sooty mold control starts with controlling the insects. Horticultural oils and neem oil are effective on aphids, and especially scale. You can also rinse off the aphids with short blasts of water.
You should also prevent ant populations from accessing the bushes. Ants will actually herd aphids and protect and care for these pests in order to have a constant supply of honeydew on which to dine.
Fungus on Camellias
In addition to camellia sooty mold, fungal spores of other types may take up residence on the leaves and stems of the plant and cause damage. Fungus on camellias may show up as water spots, dark or halo-like areas, or even just dry edges.
Fungal spores are airborne and can affect many types of ornamental plants. They are worse in moist, warm periods and their effects can be minimized with fungicides and by avoiding direct overhead watering.