Tuesday, September 9, 2008

Thanks, Mother Nature

Ah rain. Until Hanna delivered a few inches last weekend, we were in a drought. What’s a drought ? The National Weather Service says an agricultural drought refers to a situation where the amount of moisture in the soil no longer meets the needs of a particular crop.

The effects of drought on annual garden plants such as vegetable and flower gardens are obvious. Certainly the needs of these plants were not met as August yielded less than an inch of rainfall in most of Bucks County….less than half and inch in my neighborhood. But what concerns me more is the long term effect of drought on perennial plants, especially trees. For the last two weeks I’ve observed severe stress symptoms on many trees and shrubs. They will revive and survive but in many cases this stress will lead to disease and failure in years to come. Penn State’s plant disease clinic receives many plant samples each year and has correlated the incidence of drought and certain diseases of woody plants, especially botryosphaeria canker on rhododendron, dogwood, redbud and crabapple and cytospora canker on spruce. These diseases lead to severe branch cankering and dieback.
During the drought of 1999, which was extreme, I observed stress on many woody plants that lead to plant decline and death in the years that followed. Here at Neshaminy Manor Center, home of the Almshouse Arboretum, we watered trees that were planted in 2007 and 2008 to insure that they will thrive in years to come.

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