“Limelight” grows up to 8 feet tall and is topped with pure white flowers that will change to chartreuse green and mature to a dark rose in the summer. (Photo by Ginny Rosenkranz)

Hydrangea paniculata, or the “Panicle Hydrangea,” is one of the most cold hardy of all the hydrangea — and because they bloom on current seasons growth, they are guaranteed to bloom every summer.
These beautiful shrubs grow 10-20 feet tall depending on the variety, but bloom best if they are pruned in the fall or early spring to encourage new growth that will produce their lovely flowers.
A simple way to get the largest flowers every year is to prune the branches out leaving only five to 10 branches coming up from the roots.
Most of the Panicle Hydrangea have very sturdy branches, however, when they bloom the weight of the flowers cause the branches to arch gracefully over.
The leaves are a nice medium green in summer, creating a nice background for the pure white and pink or white and lime green flowers.
The flowers are four-petaled with some as large as an inch across, and they are all gathered together on a 6- to 14-inch bouquet in the shape of an ice cream cone.
The large flowers are sterile and the small flowers are fertile, making them a welcome addition to the garden for butterflies and other pollinators.
Most of the flowers start out white and mature into pink, rose, reddish purple or red depending on the variety.
“Limelight” was one of the first of the new more compact plants that can grow up to 8 feet tall and is topped with pure-white flowers that will change to chartreuse green and mature to a dark rose in the summer.
Another beautiful flowering Hydrangea is “Pinky Winky,” with bouquets of flowers up to 12 inches long, with the larger flowers starting out white and quickly turning pink, giving the plant a two-toned look.
The smaller fertile flowers are almost hidden by the larger sterile flowers, but the pollinators have no problems finding them.
“Sweet Summer” is also a compact shrub growing only 5-6 feet tall and wide that becomes completely covered with white to soft pink flowers in summer.
All of these colorful shrubs can also be found trained to grow upright as a tree form.
These trees grow 8-10 feet tall and need to be sheltered from the wind, and need to be pruned to keep them as a tree instead of a shrub.
(Editor’s Note: Ginny Rosenkranz is a commercial horticulture specialist with the University of Maryland Extension.)