GARDENING: Premature leaf drop problems showing up

You will never hear me complaining about rain when we need it! We were quite dry but have gotten at least three inches in the last few showers.

According to the Ohio Agricultural Research and Development Western Branch weather station (South Charleston, Ohio), we were 2.75 inches below normal in precipitation in July. Combined with the average high temperature of 86.6F, it’s no wonder plants were dropping leaves.

Looking around the area you see many leaves on the ground way before it’s time for normal leaf drop. Plants will drop leaves, fruit and flowers during extreme heat and dry weather to survive.

Photosynthesis slows and can’t keep up with the needs of the plant. Thus, it sheds excess “weight” so to speak; leaves fall first followed by flowers and fruits.

As you look around, you can see some trees are more affected than others. Honeylocusts and lindens for instance had leaf litter all around the tree. We had a ginkgo in Snyder Park Gardens and Arboretum shed its fruit in early July, long before the normal fall drop.

Credit: Contributed

Credit: Contributed

The same thing occurs to your flowering annuals if you let them dry out continuously. The flowers will drop first followed by slow flower production unless the plant is watered. Extreme drying out leads to lack of recovery.

No need to worry about this premature drop unless there is also branch dieback on trees and shrubs. This indicates that the plant experienced root damage. You may have to prune off dead branches.

If the tree or shrub was newly planted and is completely defoliated, don’t give up on it. Check the tissue under the bark; if it’s still green, there is hope. If it’s completely brown, it’s likely the plant is done.

Another problem you see is leaf scorch. Trees and shrubs that are susceptible to leaf scorch may be holding onto their leaves, but the leaves are brown.

Leaf scorch symptoms show up around the margin or outside edges of the leaves. Trees that are susceptible to leaf scorch include Japanese maples, buckeyes, and horsechestnuts. If the trees have blotches or dead areas in between the margins and not on the edges, it’s likely a disease and not leaf scorch.

Depending on the weather for the rest of this season, you may want to deep water newly established trees and shrubs. Don’t let them go into the winter months dry or you may lose them completely.

In addition, don’t fertilize plants while they are under stress. Fertilizers are composed of salts and high salt levels in soils will compound problems if the roots aren’t healthy.