The Kwanzan cherry tree is a medium-sized ornamental that can reach heights up to 25 feet. This showy tree develops pink flowers in the spring and produces rich, green foliage that turns to shades of copper and orange in the fall. The Kwanzan cherry tree is intolerant of drought and sensitive to stress and pests. This tree is also susceptible to several diseases that can quickly damage the tree if left untreated.
Verticillium wilt is a persistent soil-borne disease that can thrive for many years in the soil without a host. This fungal disease attacks the Kwanzan cherry tree through its root system and infects the tree's vascular system. As the disease develops, it restricts the xylem tissue and prevents the flow of water and nutrients throughout the tree. The foliage around the lower area of the tree will begin to yellow and drop. As the disease progresses, the yellowing will climb to the upper parts of the tree. The infected Kwanzan will also experience growth stunt and dieback of twigs and branches. The wood of the infected tree will display a brownish-red complexion. Verticillium wilt is a fatal disease that cannot be controlled with chemical treatments. Infected Kwanzan trees must be removed and destroyed.
Cherry Leaf Spot
Cherry leaf spot is a disease that infects the leaves and stems of the Kwanzan cherry tree. This fungal disease travels by fungal spores that are carried by wind and rain during the wet spring season. These fungal spores germinate on the young, developing leaves, and the tree will show symptoms of infection within two weeks of initial contact. The foliage of infected trees develops small, purple-colored spots that turn brown as the infection progresses. These browning spots indicate the necrosis of the leaf. These necrotic areas eventually fall from the infected leaves, leaving the foliage riddled with holes. The Kwanzan tree will also experience premature defoliation, growth stunt and reduced shoot growth. Cherry leaf spot can be controlled with the application of scheduled fungicidal treatments.
Black knot is a fungal disease that develops slowly over the course of several growing seasons. Like many fungal diseases, this disease travels by fungal spores that are most active during the wet, rainy periods of spring. The fungal spores infect the woody areas of the tree and cause the development of dark-colored galls. These galls are initially tiny and increase in size throughout the years. These galls house fungal spores that cause secondary infections when they are released. Black knot is controlled with a combination of pruning and fungicidal treatments. The infected areas must be pruned from the Kwanzan during the winter months while the spores are inactive.