Hydrangea health
Mary Asked
I have two Little Lime hydrangeas in large pots. They have some disease – brown spots on them- any way to prevent this in late summer? Secondly, when should I prune them and how much should I remove?
Thank you.
The Gardener’s Answer
Hi Mary, Thanks for sending the reference photo of your Little Lime hydrangeas. Overall, they look very healthy. These panicle hydrangeas are relatively disease resistant but can be affected by fungal diseases which is likely what has caused the sporadic brown spots on your shrubs. The most common fungal disease is known as Cercospora leaf spot. Hot humid conditions and rainfall/overhead watering contribute to the spread of this disease. In more severe cases a fungicide could be helpful but, in your case, removing and disposing of the infected leaves should be all you need to do to prevent further spread. Good air circulation is also important. These brown spots are not aesthetically pleasing but will not impact the overall health of your plant.
Prune in late winter or early spring before new growth begins. Remove damaged, thin or crossing branches and cut back stems to reduce the height of your shrubs. If you want to shape or reduce the size of your hydrangeas, cut the stems back by no more than one-third of the overall size. This will encourage new growth. Little Lime hydrangea bloom on new wood that will develop later in the spring. You don’t need to worry about removing potential flowers like you would on hydrangeas that bloom on old wood. I like to leave the dried flowers for winter interest, but they can be removed anytime without damaging the shrub.
Angie Oakley
Kentucky Living-Ask the Gardener
