Ornamental & Tree Diseases

Plant Disease Dispatch Sheets
September 25, 1997

M-307 - Diseases of Holly

Hollies are among the most popular ornamental trees and shrubs and may be used in the landscape for purposes such as hedges, screens, specimen, or accent plants, barriers, shade trees, foundation and border planting, foliage and berries for Christmas decorations, and as a source of food and cover for birds and wildlife. Many of these species are native to this country. With the many available species and varieties for the wide range of uses mentioned above, one can easily understand why the hollies continue to gain popularity as a desirable landscape plant.

In general, the hollies are extremely hardy and are usually grown and perform best in a slightly acid soil. Also, like other plants, they perform better in well-drained soil.

Hollies for the most part are subject to attack by only a few disease-causing organisms. Many times poor appearance of plants is often caused by improper planting, dry weather, cold damage, and planting varieties that are not adapted to our area. The amount of damage from diseases on hollies can be minimized by giving plants plenty of growing space, drainage, and pruning out all diseased twigs and branches as they appear.

There are several leaf spots which occur on holly. Of these, tar spot is the most severe. This fungus disease may occur at any time during the growing season; however, it is more prevalent during the moist, cool periods of early spring.

Yellow spots are the first sign of this disease. These spots later turn dark brown and by fall are almost completely black. When possible, diseased leaves should be gathered and destroyed.

This sanitary step should be followed by several applications of a broad spectrum fungicide such as maneb, ferbam or a copper fungicide, such as Bordeaux mixture. As an added plus, these fungicides are also effective for other leaf spots and die-back which occur on hollies.