As a landscape designer, I am often questioned as to when and how to prune the various types of hydrangea. The next welcome addition to your landscape could be one of the many show-stopping varieties of this plant and proper pruning is the key to successful blooms!
Generally, hydrangea either bloom on the “old wood” of the previous season, “new wood” of the current season or a combination of both. There are many types of hydrangea including the mopheads, lacecap, panicle, mountain, smooth, oakleaf and climbing. The Mopheads (Hydrangea macrophylla) have been the most widely planted hydrangea in home landscapes over the years and are usually blue or pink in color with large leaves. Hydrangea ‘Nikko Blue’ is very well known in the landscape for its large blue ball-shaped flowers that bloom towards the later part of the summer and deepen in color as they mature. ‘Nikko Blue’ Hydrangea does bloom on old wood, which means that if you are looking to prune your plant it needs to be done immediately after flowering before the fall. Hydrangea ‘Nikko Blue’ grows best in moist, well-drained soil in partial shade. It reaches 3-5 feet in height and is hardy to USDA Zone 5.
A newer alternative to the “old fashioned” variety of hydrangea is the Hydrangea ‘Endless Summer’ collection, which blooms on both old and new wood and ‘All Summer Beauty’ that blooms on the new growth of the season. Both of the later mentioned also have a much longer bloom time and repeatedly bloom throughout the summer. Each of these plants grows to approximately 3-5 feet in height, each grows best in partially shaded conditions (afternoon shade) and moist well drained soil and are hardy to USDA Zone 5. Hydrangea macrophylla ‘Blushing Bride’ in the Endless Summer Collection displays white blooms that turn pink with age. For these varieties that bloom on the “new wood” of the season, spent blooms and dead wood from the inner portion of the plant can be pruned out in either fall or early spring.
Hydrangea ‘Pia’ is a miniature French hybrid with broad pink flowers growing only to 2 to 3 feet in height, a good candidate for small spaces in zones 5-9. ‘Pia’ grows best in partial sun with afternoon shade and prefers a rich organic soil. Pia hydrangea bloom on old wood and generally need little to no pruning; however, if needed, prune immediately after flowering by cutting back flowering stems to a point of healthy buds. An alternate that blooms on the new wood of the season is the Cityline Series from Proven Winners, a dwarf hydrangea hybrid that matures to just 2-3′ tall by 3-4′ wide.
Another variety of Hydrangea ‘macrophylla’ is the Lacecap Hydrangea that displays a smaller inner circle of lace-like flowers surrounded by a ring of larger showier flowers. A favorite is Hydrangea ‘Tokyo Delight’ that displays beautiful cobalt blue flowers with an inner ring of delicate white flowers, grows to 4-6 feet and blooms late July through August, prefers afternoon shade, moist well drained soil and is hardy to USDA Zone 6. Prune Hydrangea ‘Tokyo Delight’ immediately after bloom since new buds form on the older wood from the previous season. An alternate lacecap hydrangea that blooms on both old and new wood is Hydrangea ‘Twist-n-Shout’ from the Endless Summer collection with beautiful blooms that turn to a purple-blue in a more acidic soil. Twist-n-Shout’ is hardy is USDA zones 4-9, grows 3-5 feet tall by wide and like all plants in the Endless Summer Collection, produces blooms on both old and new wood.
Hydrangea paniculata ‘Grandiflora’ or the ‘Peegee’ Hydrangea is a personal favorite of mine for extremely large pyramidal white blooms in July throughout fall and abundant fragrance in the garden. Hydrangea ‘Peegee’ can be grown as a shrub or tree form and can serve as either a group planting or as a single specimen in a landscape design. Hydrangea ‘Grandiflora’ also grows 3-5 feet or higher in its tree form. This particular hydrangea can grow well in full to partial sun and blooms on new wood. Sent to the US from Japan in 1861 this beauty is a showpiece in the garden and is hardy in Zones 4-8.
Panicle hydrangea are known for being the most cold hardy and are very tolerant of pruning. They can reach a height of ten to fifteen feet or can be pruned to keep more compact. For a similar look to ‘Peegee’ with creamy-white panicle-shaped blooms and a more open look is Hydrangea ‘Tardivia’. Hydrangea paniculata ‘Limelight’ is a newer introduction with beautiful elongated lime colored panicles that bloom in late summer and last through fall. Hydrangea ‘Tardivia’ and ‘Limelight’ (6-8 feet high by wide) both do best in full to partial sun and bloom on new wood. Hydrangea ‘Little Lime’ is a more compact version of ‘Limelight’ and also blooms on the new wood of the season.
Hydrangea arborescens ‘Annabelle’, a native of the U.S., is a more shade tolerant hydrangea that produces showy ball shaped white blooms in summer, grows 3-5 feet in height and is hardy to USDA Zone 3. ‘Annabelle’ blooms on new wood and can be severely pruned in winter in order to restore shape.
The last two varieties of hydrangea are Hydrangea quercifolia or ‘Oakleaf ‘Hydrangea and Climbing Hydrangea. The Oakleaf hydrangea serves as an excellent plant for massing in a woodland setting. The name ‘Oakleaf’ comes from the oak-shaped leaves that turn a bright mahogany red in fall for a brilliant display. The upright panicles of large white flowers appear in June and the plant has a rounded habit, grows 4-6 feet in height and is hardy to USDA Zone 5. Hydrangea quercifolia does well in partial shade in a well drained most soil. This hydrangea blooms on old wood and should be pruned immediately after flowering. Climbing Hydrangea (H. anomala petiolaris) is an upcoming variety becoming more popular in the landscape. As the name implies this hydrangea once established produces vigorous vines and a profusion of lightly scented blooms. Climbing Hydrangea bloom on “old wood” from the previous season.
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