shrub disease


Astilbe Perennial Shrub Diseases:   Flower Failure: Symptoms – Plants do not flower but otherwise appear healthy. Management – Divide and replant to alleviate overcrowding. Foliar Nematode: Symptoms – Brown areas on the leaf are restricted in shape by leaf veins. These angular spots are usually seen on the lower leaves. Management – Remove the leaves […]

Astilbe Perennial Shrub Diseases – Symptoms & Control


Lilac Shrub Diseases   Ascochyta Blight   Symptoms In the Spring, the current year’s shoots and flower stalks are girdled, wilted, and brown. The base of the dead area is tan to gray and shriveled. In wet weather, dark gray pimple-like fungal fruiting structures dot the dead tissue. In Summer […]

Lilac Shrub Diseases


Hydrangea Shrub Diseases   Botrytis Blight   Symptoms Petals turn brown and fall. Leaf spots form, especially where faded petals have fallen. Flower buds are killed before opening.   Management Space plants to insure good air circulation. Maintain low humidity. Avoid watering late in the day. Remove crop debris. Apply […]

Hydrangea Shrub Diseases




Cedar Apple Rust and closely related diseases, cedar-quince, cedar-hawthorn, and Japanese apple rusts are caused by fungi belonging to the genus Gymnosporangium. These fungi require two different living host plants in order to complete their life cycles. If either host plant is not present, the fungus dies. Juniper, sometimes called […]

Cedar Apple Rust & Related Rusts on Ornamental Trees