Did rains damage area plants?

Published 12:00 am Saturday, August 21, 2010

We started receiving calls Wednesday afternoon about the impact of the excessive rainfall. We had some areas of Adams County receive well over 12 inches from Wednesday through Thursday afternoon. The good thing about Adams County is we have excellent geography for handling excessive rainfall compared to other parts of the state. After seeing more than 10 inches of rain in the Kingston area Wednesday, by Thursday morning creeks and ditches were down to almost normal levels.

However callers called and asked if this much rain caused damage to plants and gardens? Here are some answers for you.

Q. Will all this rain affect my vegetable garden?

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Right now, a lot of people are transitioning from summer to fall gardens so the timing was somewhat good for those in the transition stage. I haven’t had any reports of trouble but the main problem to look for after excessive rainfall is water wilt. This is common in tomatoes but may also affect peppers, beans and other garden plants.

The first sign of water wilt is a slight wilting of foliage in the top of plants following several inches of rainfall within a short period. The wilt continues and the entire plant may collapse within six to 12 hours. Plants growing in well-drained soils generally recover within a day; however, vegetables planted in heavy, poorly drained soils may not be so fortunate. As a result of poor drainage, roots may be exposed to waterlogged soil conditions for several days, and this often leads to death of tomatoes or other affected garden plants. Under soggy soil conditions, roots use up available supplies of gaseous soil oxygen, which is replaced by toxic levels of carbon dioxide. Roots can’t survive without oxygen, and extended periods without this essential element lead to plant death. If you have poorly draining soil and have this problem, now is a good time to consider making raised-row gardening part of your future vegetable production program.

Q. How are the recent rains affecting my trees?

I would not worry too much about trees in our areas after this week’s rain, in fact is was probably a positive thing from an environmental standpoint. Certain trees like the American beech, crabapple, flowering dogwood, hawthorn, southern magnolia, pecan, peach and redbud are more susceptible to problems with excessive rainfall, but usually that is when conditions exist over a long period of time.

When roots are exposed to standing water for extended periods, roots often die from “anoxia,” a term which means oxygen starvation. Damage occurs to trees and shrubs in obviously wet areas in the home landscape. Since damaged plants lack the ability to pick up water because of damaged root systems, one of the first symptoms of damage from soggy soils is wilting. Affected trees and shrubs may also show symptoms of nitrogen deficiency (leaf yellowing) after the soil drains.

Plants exposed to prior flooding become more susceptible to phytophthora root rot or collar rot. However, don’t stress about older mature trees, most full-grown, well-established trees and shrubs should cope well even after the worst rains. Despite some erosion problems in some areas and short-term flooding I think the Miss-Lou came out of the flash floods in good shape.

David Carter is the director of the Adams County Extension Service. He can be reached at 601-445-8201.