Hydrangeas: To Prune or not to Prune

When it comes to hydrangeas, the one questions most frequently asked is: why do my hydrangea not flower? Your hydrangeas may look healthy and full but still do not bloom. Many homeowners think it’s a soil nutrient or pH problem. More times than not, it’s either due to winter damage or the issue can be traced back to incorrect pruning. Here are my suggestions for pruning your hydrangeas here in the greater Rochester Area.

Regardless of the variety, do not prune your hydrangeas in the fall.  You never know how much die-back Mother Nature is going to cause, or what type of a “winter tax” she’s going to extract. Wait until winter has passed and only cut off the deadwood. Sometimes this means you’ll be cutting them way back to the ground because they’ve died back that far. Some years will require minimum pruning. Leave as much green living wood as possible because it is the foundation of the current year’s new growth and potential flower.

Generally speaking, most varieties of hydrangeas do not require pruning green wood. However, understanding what type of wood your hydrangea blooms on, I.E. new wood (current years’ growth) or old wood (last year’s growth) tells you when to prune if the need arises.

Those that flower on old wood require minimal work. In the spring, prune only old, weak, dead or diseased branches and canes; never prune off green or living wood because you may be removing flower buds that developed the preceding year. In the summer you may remove spent flowers immediately after they’re done. In special instances pruning may be required on overgrown specimens to re-shape those that need it. This is done late summer after their flower cycle is completed. These varieties tend to flower earlier because they developed their flower buds the previous year. “Big Leaf” or Hydrangea macrophylla varieties fall within this category.  Examples include Cityline® Mars, Cityline® Paris, Cityline® Rio and Cityline® Venice.

Hydrangeas that flower on new wood (this year’s growth) will flower later because they have to grow out their new branches or canes. They may be pruned late winter or early spring leaving as much living green wood on the plant as possible because it contains much of the stored energy they need for growth and potential flowering. The Hydrangea arborescens or “smooth hydrangea” are in this group; Annabelle, Incrediball®, Invincibelle® are examples. Hydrangea paniculata “hardy hydrangea” have a number of different varieties available such as Bobo®, Limelight, Littlelime™, Pinky Winky® and Quick Fire®.

There are popular newer varieties that flower both on current year wood and old wood during the same year that we carry at Van Putte Gardens. The Endless Summer®, Forever & Ever®, and Let’s Dance® series are all re-bloomers. Pruning is virtually unnecessary with these varieties and they’ll give you two flowering cycles, late spring and late summer, each year.

If you’re not sure what variety you have, take some pictures, snip off a leafed out branch or cane, and bring it to Van Putte Gardens where one of our green thumb staff will assist you determine what kind of hydrangea you have.

Success with your Gardening, Naturally!

Written by Rick Stecher, Garden Center Manager