shrub diseases


Species of fungus-like organisms belonging to the genus Phytophthora are soil-borne or plant-borne and all are plant pathogens. Some species of Phytophthora attack woody ornamentals including Arborvitae, Azalea, Dogwood, Forsythia, Fir, Hemlock, Holly, Juniper, Maple, Rhododendron, and White Pine. Other species attack herbaceous plants including Annual Vinca (Catharanthus), Begonia, Poinsettias, […]

Phytophthora Root Rot on Woody Ornamentals


 Perennial Diseases   Yarrow:  Diseases of Yarrow-Botrytis on yarrow flowers are often seriously inflicted with the disease Botrytis. Botrytis known as gray mold appears as brown dead areas and under proper moisture   may have a gray fuzzy appearance. It attacks buds, flowers, leaves, and stems. It may eventually kill […]

More Perennials and Perennial Diseases!


 Viola Perennial Shrub Diseases:   Aster Yellows: Symptoms – Leaves are yellowed and narrow rather than oval. An abnormally high number of shoots form. Management – Remove infected plants. Control leafhoppers.   Bacterial Infection: Symptoms – An abnormally high number of shoots form Management – Remove infected plants. Black Root Rot: Symptoms – Plants are yellowed, stunted and die. Management – Try […]

Viola Perennial Shrub Diseases – Symptoms & Control



 Rudbeckia (black eyed susan) Perennial Shrub Diseases:   Aster Yellows: Symptoms – Leaf-like structures form where flower parts should be located. Plants may branch abnormally heavily (witches’ broom), leaves may be yellow and plants may be stunted. Management – Remove and destroy infected plants. Control leafhoppers early in the season with insecticides in order […]

Rudbeckia (Black Eyed Susan) Perennial Shrub Diseases – Symptoms & ...


 Blanket Flower Perennial Shrub Diseases:   Aster Yellows: Symptoms – Leaves are yellowed and flowers do not appear normal or of good quality. Management –  Remove and destroy infected plants. Control leafhoppers early in the season with insecticides in order to suppress spread of the pathogen   Bacterial Leaf Spot: Symptoms –  Areas between veins […]

Blanket Flower Perennial Shrub Diseases – Symptoms & Control


 Coreopsis Perennial Shrub Diseases: Aster Yellows: Symptoms – This virus is moved from infected clematis and some weeds by nematodes. Remove infected plants Management – Maintain good leafhopper control and eliminate nearby weeds that harbor aster yellows.   Bacterial Leaf Spot: Symptoms – Irregular brown blotches and spots develop on leaves Management – Water in a manner that […]

Coreopsis Perennial Shrub Diseases – Symptoms & Control



 Coneflower Perennial Shrub Diseases: Alternaria Leaf Spot: Symptoms – Small dark brown to black leaf spots become oblong and develop lighter-colored centers as they enlarge. Spots on young plants are often along the midrib. Management – Water in a manner that keeps moisture off the leaves and stems. Apply PureSpray Green to help protect […]

Coneflower Perennial Shrub Diseases – Symptoms & Control


Clematis Perennial Shrub Diseases Leaf Spot: Symptoms – Large spots form on the leaves, become tan or black in color and may have a zonate pattern within them. Management – Ensure good air circulation around clematis stems. Remove infected leaves as they are detected. Irrigate plants in a manner that keeps water off the […]

Clematis Perennial Shrub Diseases – Symptoms & Control


Nematode Diseases
Nematode Diseases   Nematodes are soil-dwelling non-segmented roundworms, usually less than 0.02 in. long. Those that feed on plants have a hollow spear-like mouth part (stylet) that is pushed into the plant cell. The worm forces enzymes through the hollow stylet into the cell where cell components are digested and […]

Nematode caused Diseases on Woody Ornamentals



Boxwood Diseases Decline   Symptoms Stunted growth and dieback occur. Young foliage turns grayish green or bronze and finally straw colored. Old leaves fall prematurely. Middle or top branches die. Sunken cankers form at the soil line or on branches in the crotches where dead leaves accumulate. Wood under the […]

Boxwood Diseases


          Botryosphaeria Canker   Symptoms Rough, sunken, dark-brown areas form around wounds or natural openings in the bark. The wood of a recently killed branch is lighter brown than the pith. Dead bark falls off the cankered area. Leaves on affected branches wilt as affected branches […]

Azalea & Rhododendron Shrub Diseases