Three years ago, we planted a hydrangea standard in our garden. Presently, it is about 6 ft high with its head being about 1.5 ft in height with a diameter of about 2.5ft. In strong winds, the 1.25 inch diameter trunk bends excessively.
Other than providing vertical support for the trunk, is there a fertilizer to increase the diameter of the trunk, or, should the size of its head be pruned to a smaller size to prevent the excessive amount of bending? THANKS
We appreciate your concern for the excessive bending of your lovely standard hydrangea, however, Hydrangea paniculata, generally used for standards, is the hardiest of the genus, and hardy to zone 4. The heavy flower-heads can be damaged from high winds, so sheltering the tree from the wind is recommended. Suggestions including other plant material or trellis fencing are mentioned in Trees and Shrubs for Flowers by Glyn Church, available in the Toronto Botanical Garden Library.
Regarding vertical support, It is often better not to stake a tree. This will ultimately strengthen the roots and the trunk. See article by expert Lee Reich
Proper pruning is also impotartant to maintain the overall shape and health of your standard Hydrangea. Pruning is a method of controlling growth, shape and enhancing the quality or quantity of flowers and fruit on trees and shrubs. Please refer to our post to similar questions for information on how to prune your Hydrangea standard: Pruning a hydrangea tree, Hydrangea paniculata (tree)
We hope that your tree increases in girth and strength each year.