Leaf Drop in Mid-Summer

After experiencing a five year drought, many homeowners are finding a new set of problems with seasonal rains. Recent heavy rains have
brought a lot of water to unexpecting plants which are reacting very strangely.

One might expect to see gorgeous lush, green foliage and abundant growth. Instead, we are seeing leaf yellowing and reddening, premature
leaf and fruit drop. The most common plants I've received calls on this summer are maple, dogwood, pear, birch, and a wide range of shrubs.

When soils are saturated, especially in North Georgia's heavy clay soils, oxygen is prevented form reaching the root system. Certainly some trees are more tolerant of wet conditions, but the longer the lack of aeration, the greater the chance of root death.

Lack of oxygen will result in root die-back, with above ground symptoms appearing as leaf yellowing, droopy foliage, leaf drop, and eventually, branch dieback. Water-logged root systems are also more susceptible to
attack by root-rot organisms.

In addition to the obvious damage to plants, there are more long term effects to the soil. Soil microorganisms that require oxygen may be killed and those that survive without oxygen take over, which in the turn affects the availability of nutrients for plant use. The soil structure itself may be physically harmed due to compaction of soil particles._

There isn't much one can do other than wait for drier weather to prevail and allow water to drain. As more favorable conditions return, watch for signs of dieback, but don't be too hasty to cut limbs.

Branches that have lost leaves aren't necessarily dead; even though leaves may drop, there may be buds that will be able to re-leaf next summer. Live stems and buds will have some green tissue visible.

You may want to thin down your mulch layer, in particular if it is placed too close to the trunk of the tree. This may allow the soil to dry out a little faster. Also, a light fertilization may be helpful to replace
nutrients that were lost and to encourage re-growth. I would suggest 6-12-12 or 5-10-15.

Billy Skaggs
Agricultural Agent
Hall County Extension Coordinator
734 East Crescent Drive
Gainesville, GA 30501
Phone:(770)531-6988
Fax: (770)531-3994
Email: [email protected]