Hydrangeas can present a bit of a conundrum for gardeners when it comes to care and pruning because there's no single method that's right for all hydrangeas. For example, 'Limelight' hydrangea care may differ from 'Endless Summer' hydrangea care. Many gardeners are hesitant to prune hydrangeas because they think it is counterproductive to get rid of the blooms, but that couldn't be further from the truth. Pruning your hydrangea blooms will only help your shrub's growth for next year.
Hydrangeas can be planted at almost any time of year, except when the ground is frozen in winter. Plant your hydrangeas at the depth they're at in their pot. Be sure to look at the guidelines on the plant tag to be sure that you space the plants properly. Some hydrangea varieties, like oakleaf hydrangea, get quite large, while others are bred to be dwarves. When it comes to hydrangea soil, be sure that you're planting your shrub in a pourous, moist soil.
Interested in growing Vanilla Strawberry hydrangea? See our planting guide.
When pruning a hydrangea, it's best to take off no more than one-third of the plant at any one time. Your objective also determines how you prune it. If you are just doing some shaping of plants that are too tall, you want to take the top growth down a little. If you need to do a severe pruning or rejuvenate the plant, you may want to take the branches all the way down to near the ground.
Pee Gee hydrangea (Hydrangea paniculata, which includes varieties such as 'Limelight') as well as smooth hydrangea (Hydrangea arborescens, also called seven bark and best known for the variety 'Annabelle') bloom on new wood. Timing for the pruning of these types of hydrangea is not as critical—you can prune in winter or early spring and they will grow and flower in the same season.
Big leaf, or mophead, hydrangea (Hydrangea macrophylla) and oakleaf hydrangea (Hydrangea quercifolia) both bloom on the previous season's growth. If you prune these at the wrong time of the year, they either won't flower or will flower sporadically. They should be pruned soon after flowering in summer, and never too severely—less than one-third of the plant at any one time.
Some newer varieties of big leaf hydrangea, including the popular 'Endless Summer', have been bred to bloom on new wood as well as old wood. This makes them better for cold climates because even if the old stems suffer cold damage, new growth will still bloom. This also provides more flexibility in pruning, since you can prune it at any time of the year and it should still bloom. Even so, pruning right after bloom will maximize flowering.
Along with pruning, properly watering your hydrangea is crucial—the prefix of the plant's name, hydra, even indicates so! Even a day or two without water can affect your hydrangeas, so be sure to water them often. If you notice that your hydrangea shrub is wilting, give it a good dose of water and it should perk back up.