It’s the summer of the hydrangea

By: 
Rob Zimmer
Columnist

My favorite flowering shrubs of the summer season are the beautiful, lush hydrangeas that fill our landscapes and gardens with their billowy blooms and elegant form. A must-have for every garden and providing a long bloom season from July all the way through Halloween, hydrangeas come in many forms, colors and sizes. Chances are there’s a hydrangea for every spot in your yard and garden.

While garden centers are filled with colorful hydrangeas during the spring gardening season, it is important to do your research and select varieties that will grow here in our area. Many of those sold at garden centers are not reliably hardy here in northern Wisconsin. Visit a reputable, local nursery or garden center to select your hydrangea varieties. The ones covered in this column are perfect for our area.

Hydrangeas come in five basic types, or farms. There are the smooth hydrangeas, such as the ever popular Annabelle. These are normally lush, mophead varieties.

There are panicle hydrangeas, or those that resemble cones or pyramids in bloom. Many popular hydrangeas for our area are panicles.

Big leaf hydrangeas are the ones that are often tricky to overwinter here in our area. This includes the popular Endless Summer series and many others. Special care needs to be taken with these plants over the winter season.

Climbing hydrangeas are lush, woody vines that can grow quite large and feature massive, white, lace cap blooms.

Oakleaf hydrangeas are also touchy here in our area but provide fascinating foliage that is especially colorful during fall. Many people grow oakleaf hydrangeas for the foliage alone, not caring if the plant blooms or not.

Hydrangeas in the Annabelle series or smooth hydrangeas are quite simple to grow in our area. Many of these require a bit of shade, so be sure to site accordingly. Research online or follow the directions on the plant tag. Smooth hydrangeas come in more than white. There are many varieties that are pink, even reddish in color. Some of my favorite smooth hydrangeas are Mini Mauvette, that blooms in reddish pink, Incrediball, Incrediball Blush, Invincibelle Spirit, Garnetta and Limetta.

The panicle hydrangeas are becoming the most popular variety of hydrangeas in our area. This group of hydrangeas includes the highly popular Limelight, as well as Pinky Winky, Quick Fire, Vanilla Strawberry, Bobo, Little Lime, Firelight, Diamond Rouge and many more.

Panicle hydrangeas, along with smooth hydrangeas are the easiest to grow here in our area and require very little care. They bloom on newly formed wood each year, so can be cut back in fall or late winter to about 1 foot in height. I recommend allowing the beautiful flower heads to remain standing all winter, because they look amazing when tufted with fresh snow.

Most panicle hydrangeas transform through several color phases throughout the season. Panicle hydrangea start out creamy white or lime green, then gradually turn pink, even red throughout summer and fall. By September and October, many of these hydrangeas are a deep, rich red in color.

Big leaf hydrangeas are the tricky ones to grow here in our area. This is because they bloom on old wood each year, the branches that were formed in the previous season. If you cut them back, or if they freeze off during the winter, then you will get lots of leaves the following year but very few blooms. For this reason, it is important to protect the entire plant, stems and all, over the winter season. Many gardeners have found the best success by simply digging the plant up overwinter and storing it in an unheated basement or garage where temperatures won’t fall severely during winter.

Big leaf hydrangeas include the Endless Summer series, as well as Cherry Explosion and others. Again, take care with these plants. Even though the root systems are hardy here, the flowering branches and buds must be protected

A few varieties of big leaf hydrangea will bloom on both new and old wood, making them a better choice for our area since they will still bloom even if the flower buds on old wood have frozen off.

Climbing hydrangeas are popular for large spaces since they grow quite extensively. Often, we see them creeping up the sides of silos and barns.

Often, gardeners assume that hydrangea color can be changed by altering the pH of the soil. While this is nice in theory, in reality it rarely works. While chemicals are sold that can be added to the soil, it generally is never enough to fully transform the color. Additionally, this process only works on certain big leaf hydrangeas. It will not work on smooth hydrangeas or panicle hydrangeas as the colors they bloom in are their permanent color. Don’t be taken by this gimmick.

Enjoy the summer of the hydrangea.


Find Rob Zimmer on Facebook at www.facebook.com/RobZimmerOutdoors.

Category: