Hydrangeas are a garden staple. These versatile plants provide visual impact as both specimens and mass plantings. Easy to grow, Hydrangeas offer a tough constitution and prolific blooms that last all summer. There’s a hydrangea for nearly every garden, and for good reason. In the late spring through summer, Hydrangea bloom in shades of white, pink, purple, or blue; some have fabulous fall color, as well. These colorful landscape shrubs typically like part to full shade, although there a few varietals that can tolerate full sun.
Fertilizing
Hydrangea should be fertilized twice a year, once in early spring and again in early summer. Apply a slow release 10-10-10 formulation when your Hydrangea is just beginning to leaf out. It is also good practice to add two shovels-full of compost to the base of each plant. This is an easy way to give an early boost to your shrubs. When applying again in the summer, fertilize no later than July. This can result in the Hydrangea pushing new fleshy growth too late in the season. This tender growth may not harden off in time for impending colder weather and cause some serious damage to your hard work.
Watering
Hydrangeas are thirsty shrubs. You’ll notice that most Hydrangeas will weep on a hot afternoon here in Sandhills. Keep the soil around your shrubs moist and well-drained. Unfortunately, this can mean watering your plants more than once a day. An easy way to alleviate this issue is wrapping a soaker hose around the base of your plants. When you get home from work, you can simply turn on the spigot and let it run for 20 minutes before shutting it off. This method works two-fold: (1) It’s a quick fix for thirsty Hydrangea and (2) it significantly reduces the chance of your Hydrangea contracting fungal issues due to overwatering.
Adjusting the Color of Your Hydrangea
Did you know that some species of Hydrangea have the ability to change color?!
Hydrangea macrophylla (Bigleaf or French Hydrangea) and
Hydrangea serrata (Mountain Hydrangea) can both change color. How do these Hydrangeas change color, you ask? The pH of the soil determines the color of Hydrangea blooms. Hydrangea in strongly acidic soils (less than 6 pH) turns the blooms blue. Hydrangea in alkaline soil (more than 7 pH) will turn the blooms pink or even red! A slightly acidic or neutral soil (a pH of 6 to 7) will yield purple blooms.
Pruning
Pruning your Hydrangea depends on what species you have. To determine when you need to prune, you must first find out when the plant sets its flower buds. Most older Hydrangea set the following year’s flower buds in later summer or early fall. Some set flower buds in Spring.
Follow this chart we made, and we’ll make it easy for you: Bigleaf or French Hydrangea (Hydrangea macrophylla) Prune during the summer, just after the flowers fade.
Smooth Hydrangea (Hydrangea arborescens) Prune in late winter or early spring.
Oakleaf Hydrangea (Hydrangea quercifolia) Prune during the summer, just after the flowers fade.
Mountain Hydrangea (Hydrangea serrata) Prune during the summer, just after the flowers fade.
Panicle Hydrangea (Hydrangea paniculata) Prune in late winter or early spring.
Climbing Hydrangea
(Hydrangea anomala petiolaris) Prune as needed to control growth