Wednesday, September 3, 2008

Landscape - Long Term Effects of Drought

Drought can have long term effects on landscape plants. The following is some information on the subject.

Long-Term Effects of Drought

When an area has repeated dry periods, even if lack of rain occurs during different seasons, the long-term effects are substantial:

• Plants show increased susceptibility to diseases and insects. Typical examples of pest problems on vulnerable plants include Botryosphaeria cankers and Phomopsis cankers on redbud and Rhododendron; white pine decline; Armillaria root rot on many plants; Verticillium wilt on maples; pine wilt nematode; and borers on birches, oaks, dogwoods, chestnuts, and hornbeams.

• Plants show increased susceptibility to winter injury. Cold injury takes several forms:
— Black heart in stems of trees and shrubs
— Sun scald and frost splitting of tree trunks
— Winter burn of conifer foliage
— Dieback of overwintering broad-leaved plants.

Plants can be injured or totally killed by low temperatures at any time of year, but especially in spring and autumn, in the coldest part of winter, and when low temperatures follow warm winter periods.

• Plants can go into decline and die. Because plant food reserves needed to leaf out or regrow the following spring are reduced each time there is a drought, repeated drought can start the process of plant decline, potentially leading to death. Injuries and pests can speed up this process.

Information in part from "How Dry Seasons Affect Landscape Plants" from Mary L. Witt, Robert Geneve, John R. Hartman, Kenneth Wells, and Robert E. McNiel, University of Kentucky, Cooperative Extension.

No comments: