Hydrangea shrubs and small trees are among the most productive and problem free flowering woody plants. Just a little maintenance done in late fall will help protect your hydrangeas over the winter, and will eliminate one of your springtime garden chores.
Few plants produce such a large, showy and persistent blossom as the hydrangea family. This is most certainly a blessing, but those blossoms can endanger the structure of the tree if they collect too much heavy wet snow or ice during the inevitable winter storms we experience here in southern Minnesota.
The reason this can be a problem is that the branches of the hardy hydrangea family are more brittle than most other flowering shrubs, and can break if weighted down too much by snow and ice. The solution is easy.
Get out your pruner and/or hedge clippers and give your hardy hydrangeas a fall haircut! Cutback enough to remove the spent blossoms and a portion of the new twig growth that occurred since growth began in the spring. I usually cut back about 1/2 to 2/3 of the newest twig growth along with all of the blossoms, leaving 2 or 3 sets of new buds to push new growth the next spring. Be sure to prune when the leaves have fallen off and blossoms have turned from pink to brown.
This process usually take 30 seconds for a smaller shrub to 5 minutes for a really large hydrangea tree of 7 to 10 feet in height. Cleanup of the clippings takes a similar amount of time. Once completed, the hydrangea requires no more maintenance except a modest spring application of Osmocote timed released fertilizer. The stubby twigs remaining after your aggressive fall pruning will not catch very much snow and ice, and probably will avoid breakage.
For Big Leaf Hydrangeas such as Endless Summer and Twist and Shout, do a similar pruning, but add a layer of wood / bark mulch to help protect the crown of the plant from winter cold. Remove the mulch next spring just as growth begins.