What Is the Hardiest Hydrangea?

Hydrangea Paniculata “Limelight”

• This is one of the hardiest hydrangeas available, according to Missouri Botanical Garden. Its blooms start out white before changing to lime and then developing tinges of pink. The Hydrangea paniculata “Limelight” blooms from July to September and is suitable for USDA plant hardiness zones 3 to 8. It can handle heat, humidity and urban conditions, as well as full sun or partial shade. Because it blooms on the current season’s growth, a tough winter won’t ruin your chances for flowers when summer arrives. When mature, it stretches 6 to 8 feet tall and wide.

Hydrangea Paniculata “Interhydia”

• The Interhydia cultivar, which carries the trade name Pink Diamond, also earns high marks for hardiness from the Missouri Botanical Garden. It grows 8 to 15 feet tall and wide, producing white flowers that mature to pink hues. This shrub blooms from July to September and can be planted in USDA hardiness zones 3 to 8. It likes full sun or partial shade, organically rich soil and consistent moisture.

Hydrangea Paniculata “Pee Gee”

• Consumer horticulturist Erv Evans from NC State University calls the Pee Gee cultivar a “tough, dependable plant.” It produces 6- to 8-inch clusters of white flowers in the summer on new growth. These blooms later transform to a pinkish shade. You can grow this shrub in USDA zones 3 to 8, in sun or partial shade. It will reach a height of 10 to 20 feet and a width of 6 to 8 feet. The plant grows rapidly and prefers moist, well-drained soil, but fares well in clay.

Hydrangea Paniculata “Grandiflora”

• “Fine Gardening” magazine labels the Grandiflora as “one of the most cold-hardy species of hydrangea. You can grow it in USDA zones 3 to 8, in full sun or partial shade. Its white flowers are 6 to 18 inches long and take on pink hues as they age. This hydrangea grows 15 to 30 feet high and 10 to 15 feet wide. Missouri Botanical Garden advises to keep this fast-growing cultivar pruned to a height of 6 to 10 feet, for best shape. The flowers on the Grandiflora are suitable for cutting and drying.