Oakleafs are very temperamental when it comes to overwatering. They develop root rot when the soil stays wet for long periods of time. An infected plant can die so it is important not to overwater.

The symptoms of overwatering are the same ones as those of not watering enough because in either case, the plant growth above the ground does not get enough water. So, other than smelling the roots to see if they smell rotted, what can one do? Try watering using the finger method, monitor the wilting episodes and maintain about 3-4 inches of mulch up to the drip line.

A newly planted hydrangea shrub will wilt often, especially when it is hot and-or windy. Part of it is because its root system is not as big as it once used to be and part of it is because transplant shock. Large leafed plants sometimes suffer from this. An extreme looking wilting episode requires watering right a way (1 gallon). Otherwise, water (1/2 to 1 gallon) if the episode is not too bad but the soil is almost dry or dry. Generally speaking, a hydrangea in moist soil should recover on its own by nightfall or next morning. In future years, this should not happen as much as it does in years 1 and sometimes 2. But there will be days when the temperatures are too high or it is very windy.

If the soil is moist and the plant has not recovered by the next morning, it may be suffering from root rot.

To water using the finger method, insert a finger into the soil near the base of the shrub to a depth of 4". When the soil feels wet or moist, do not water. If it feels dry or almost dry then water and write a note in your wall calendar saying that you had to water on that day. Check the soil daily, at the same, for about two weeks. Then review the notes and determine how often you had to water. It would be something like every 3, 4, 5, etc days at a time. Then set the sprinkler or drip irrigation to give 1 gallon of water (for a newly planted small hydrangea) on that same frequency.