Hydrangeas in the Garden

Name: Hydrangeas in the Garden

Open to the public? No

USDA Hardiness Zone: 

Extension Demonstration Garden? No

Approximate year the garden/landscape was established: 2008

What to look for: Hydrangeas can provide masses of color, interesting flowers and striking foliage. This garden features a collection of hydrangeas in shrub borders and under trees, where they get the dappled light they prefer. Hydrangeas are grown with other, evergreen shrubs that provide interest in winter, when hydrangeas do not look their best.

There are many kinds of hydrangeas. There are the big mop heads and lovely lace caps (both are H. macrophylla) and cone-shaped flower types (H. paniculata). There are even climbing hydrangeas (H. hydrangeoides). Some bloom early in the season, usually June in the Piedmont NC area, and others bloom later. Then there are some that continue to bloom throughout the season, if conditions are to their liking. They also make excellent cut flowers. (Hint: Fully mature blooms will last longer in arrangements and immature ones. Soaking the entire stem and bloom in warm water for 10 minutes or so will extend the life of the cut flower.)

Some hydrangeas have blooms that respond to the soil pH. In a more acidic soil, lower than 6.0, the flowers will be blue. In alkaline soils, blooms are pink. Some hydrangeas have bloom colors that are determined by their genetics, so the pH doesn’t make a difference.

Horticulture: The challenge for the gardener is getting to know and understand the needs of the different hydrangeas. Each type has its own requirements. Some bloom on new growth, some bloom on last year's growth, and some do both. Knowing if and when to prune is important. If you have a hydrangea that blooms on old growth and you prune between late fall and early spring, you will reduce or eliminate the blooms for that year. If you are growing H. arborescens ‘Annabelle’ or similar cultivar that blooms on new growth, you may cut the plant back severely in late winter or early spring to encourage strong new growth.