Pruning Hydrangeas in Autumn
In most areas hydrangeas (Hydrangea macrophylla) can be pruned in March or April. Don’t cut back into old, grey wood. If hydrangeas are pruned too fiercely year after year flowering will be reduced to 10% or less, so just cut back the green, current season’s growth to two plump eyes or leaf buds. Leave stems that have not flowered as these will flower the following season. If you want to pick the flowers for indoor arrangements by all means do so, that is really good for the plants. Some of the modern varieties are naturally compact and need less pruning. If you live in a very cold area, you may prefer to prune your hydrangeas in spring, when the danger of late frosts has passed.