|A peegee hydrangea produces many slender stems from the base of the plant. I prune it each spring to two buds per stem on new growth but no stems gain size or strength over others. I've tried thinning the stems by cutting half of them off at the ground but this does not impact the growth pattern. The plant suckers freely and sprouts readily when a branch touches the ground. The plant sets buds well but due to the multiple stems produces very small flower clusters which the thin stems cannot support. My pruning technique is not serving this plant well . Do you have any advice?|
|This plant tends to be scraggly and loose the way you are describing it. It will be "leggier" the shadier the location and/or if it is receiving excess nitrogen fertilizer and growing overly lush as a result. |
Hard pruning would stimulate additional stems or suckers to grow from the ground, so at this point you might want to leave it alone for several years to develop some thicker branches.
The older wood will be less likely to sprout from lower buds although the natural shape is to branch out low. As the plant ages, you may eventually be able to trim away some of the lower branches to give it a bit of a "trunk" effect to shape it like a multistemmed round topped tree. It will still bend down under the weight of the blooms -- they are just too heavy for it to stay upright.
Finally, there are different varieties of this plant and some will naturally have much larger blooms than others. It is possible the variety you have produces the smaller blooms and that even the best of care will not be able to increase their size.
I'm sorry you are having such a hard time with your shrub.