Hydrangea paniculata boasts large white flowers that bloom in midsummer and last longer than the foliage. Flowers will turn pink by fall and can be used for cut flower arrangements or to make dried flowers. Pruning these shrubs is not essential, but it makes for a more attractive plant as it is a vigorous grower and can quickly outgrow its space in the landscape. Hydrangea paniculata can grow to 25 feet tall and 20 feet wide. The shrub is hardy in USDA planting zones 4 through 8.
Cut off any weak or small shoots during the first and second winters. Pruning Hydrangea paniculata while it is young establishes a strong framework.
Cut off dead and dried out flowers to give the hydrangea a tidier look. They will not all die at the same time, so this is an ongoing procedure throughout the summer and fall.
Cut dead and damaged branches as soon as you notice them. This will keep the hydrangea looking attractive and help to keep it healthy.
Trim back out-of-place shoots right after flowers start to die off. Trimming these shoots will help you to shape the plant the way you want it to look. Flower buds will come out on new shoots each spring and summer, so trimming after flowering through early spring will not cut down on next year's flowers.
Cut lower branches to the trunk in late winter to train the shrub into a tree form. The hydrangea must be planted in full sun to develop into a tree. As the plant grows taller each year, cut off branches from the ground to 6 feet high to give room to walk under the canopy.
Prune back older hydrangeas by half the size if you want to grow long stems for flower arrangements or dried flowers.