When Should I Trim My Hydrangeas?
To ensure the best performance in your hydrangeas, it is important that (if needed) they are trimmed at the appropriate time. Trimming is different between types of hydrangeas, so it will be important to identify which type you have before trimming.
Peegee - Flowers are set on new growth, so they can be trimmed either in fall or spring. In summer, wait until it is done flowering to trim. Trim off one third of the plant each year to keep it nice and full.
Bigleaf - Flowers are set on last year’s growth (‘Endless Summer’ is an exception). It is best to not trim a bigleaf unless absolutely necessary. For example, in June if there are old woody stems that did not leaf out, cut those stems back to the ground.
Arborescens – A very forgiving hydrangea in regards to trimming. They can be cut back in spring or fall and will flower on new growth. It is best to cut back to around twelve inches to keep the plant from becoming floppy.
Oakleaf - Will flower on last year’s growth. It is best to avoid trimming unless absolutely necessary. Cut out branches that have not leafed out in June. If size becomes an issue, trim just after flowering in summer.