How to Successfully Grow Smooth, Panicle, and Bigleaf Hydrangeas at Home
Adored for their fluffy pom-pom flowers, these plants are nature's cheerleaders, typically thriving throughout Zones 4 to 9. Above, 'Little Lime' panicle hydrangeas soak up rays in an upstate New York garden designed by Dean Riddle. This kind thrives in full sun, says Ryan McEnaney, communications manager at Bailey's Nursery, in St. Paul, Minnesota, and a spokesperson for 'Endless Summer' hydrangeas, while smooth types do best in partial sun, and bigleafs enjoy morning sun and dappled afternoon shade. But the various varieties require unique care for lasting impact. To ensure that yours explode with beauty every summer, heed the advice of McEnaney on snipping, soaking, and feeding them.
Know your variety.
Most hydrangeas fall into one of three categories: panicle (cone-shaped, like those shown), smooth (large and snowball-like), or bigleaf (bigger leaves—you guessed it—in tighter globes or more open, lacy petals). The first two bloom on new growth; the last erupts on both new and old (meaning the prior year's branches).
As a result, you should avoid trimming bigleafs in the fall to safeguard next year's blooms. To encourage new growth, come late winter, trim panicle shrubs by about a third, and cut smooth ones down to 12 to 18 inches tall. Then, in late spring, snip bigleafs just above the first green buds that appear. (You can also do both types in the spring if you prefer.)
Water only as needed.
To determine when that is, stick a finger in the soil up to your second knuckle. If it's dry, give it a deep drink; if moist, let it be. Overwatering can flood key nutrients and oxygen from soil.