The Pruning Technique To Try Out On Hydrangeas During July

Hydrangeas (Hydrangea spp.) are among the most beautiful summer-blooming shrubs. Hydrangea care in summer usually involves regular watering and some gentle deadheading as blooms fade. But some hydrangeas also benefit from gentle pruning in July, particularly hydrangeas that bloom on old wood. Pinch pruning is a technique that can help make your hydrangeas look fuller by stimulating them to produce more buds the following year. Pinch pruning doesn't actually involve pinching with your fingers (like when you pinch mums to produce more buds), but using pruning shears to remove the faded blooms. Also, pinch pruning is not the same as deadheading, which usually means removing spent flowers. For this task, while you may be removing some spent blooms, you're also focused on pruning deliberately to stimulate bud growth, which can mean cutting some active blooms, which can then be placed in a vase to enjoy.

Why prune hydrangeas in July? Horticulturist Lorraine Ballato recommends pinch pruning hydrangeas that bloom on old wood at this time. For hydrangeas that start forming buds in late summer and fall, lightly pinch pruning the spent flowers helps to stimulate the growth of new buds, and this can mean more flowers the following season. One of the most common mistakes when pruning hydrangeas is getting the timing wrong. It's also possible to inadvertently remove young buds, which can result in fewer or even no blooms that year. Make sure you're choosing the right timing and technique for the type of hydrangeas you have. So first you have to determine if your hydrangea produces flowers on old or new wood.

How do you know if you have "old wood" hydrangeas (the kind to pinch prune in July)? One simple way to tell is the color and shape of the blooms. The popular blue, pink, or purple mophead, broadleaf, or "big leaf" hydrangeas (Hydrangea macrophylla) bloom on old wood. This means the stems turn woody over time, and buds start forming in autumn for the following spring. Other "old wood" varieties include mountain hydrangeas (Hydrangea serrata) which include many lacecap varieties, and oakleaf hydrangeas (Hydrangea quercifolia) which typically have large white flowers.

In contrast, both panicle and smooth hydrangeas form buds on new stems in spring, hence they're considered "new wood" types. Panicle hydrangeas (Hydrangea paniculata) have cone-shaped or elongated flower trusses. Smooth hydrangeas (Hydrangea aborescens) have large ball-shaped flower clumps. Blooms are creamy white, sometimes tinged with green (like 'Limelight'), and have rosy pink tones later in the season. Some lovely new cultivars like 'Invincibelle Mini Mauvette' have pink flowers. These are best pruned in spring, though you can deadhead spent blooms if you wish at any time.

Of course, hydrangeas also break the rules sometimes. The 'Endless Summer' hybrids are broadleaf hydrangeas that bloom on old and new wood! Popular cultivars include 'Bloomstruck' (blue/pink flowers that turn burgundy in fall), 'Summer Crush' (hot pink flowers) and 'DreamCloud' (a color breakthrough for broadleaf hydrangeas with flowers of creamy white). The University of Maryland Extension says that pruning reblooming hydrangeas mid-season (i.e. July) can shorten the flowering time. They recommend removing as little wood as possible, so for these vigorous varieties, do only minimal pinch pruning to allow a longer season of flowering.

If you have old wood hydrangeas, pinch pruning is a great way to keep them looking neat in summer, as well as maximize their bud production for next year. Martha Stewart's website says that broadleaf hydrangeas can be pruned lightly, if needed, to shape them in late summer after flowering is done, and before they begin to go dormant: this advice also considers the importance of timing. Whether pruning for shape, or pinch pruning to stimulate buds, July is the perfect time.

In her article on hydrangea care in July, Lorraine Ballato gives detailed information on pinch pruning old wood hydrangeas. She says pruning before August first can stimulate new branching by forcing the plant to produce growth hormones, which means new bud formation. Pinch pruning should be done with clean, sharp pruners at a spot just above a pair of leaves. If you look closely you can see tiny new leaves forming on the stem, and should cut just above this point. She also recommends that the first stems to cut should be any that have leaves with spots, which can be caused by various fungal diseases.

When in doubt, always go slowly and step back to see how the shrub looks overall. Pruning too quickly may lead you to make pruning mistakes that can cost blooms later on. Remember that you are basically deadheading the spent flowers and don't want to cut too far down the stem. Also if you do your pinch pruning before August first as these experts suggest, you won't risk cutting flower buds that have started to form.