Hello, two years ago I planted two quick fire hydrangeas, a quick fire hydrangea in my backyard and a little quick fire in my front yard. Both have slightly grown in height and bloom but neither have sprouted new growth… they haven’t spread. The little quick fire is only about 24” high and very sparse and twiggy looking at its base. I have a lovely Annabelle hydrangea which I planted about 15 years ago which is lovely and has spread incredibly. My question is, is there hope for my two quick fire hydrangeas will spread or could there be a problem with them. …Perhaps I’m too eager. They get lots of watering, are close-ish to walls for protection and my soil is mainly clay (Don Mills, Toronto clay). Cold someone kindly provide their thoughts. Thank you!
Most shrubs, including hydrangeas, often take a few years after initial planting to develop a good roots system after which they start to visibly grow.
Hydrangeas like evenly moist soil; moist but not soggy and the soil should not be allows to dry out completely. The last couple of years, since you planted your hydrangeas, have been difficult; first a summer of drought, then a summer of practically continuous rain so that would not be surprising if it is taking a while for the root sytems to become estblished. As well, a couple of years ago we had a particularly difficult winter and many hydrangeas suffered damage – with the result that they did not bloom at all that year. That winter may have impacted the growth of your quick fire hydrangeas.
As hydrangeas prefer a moist rich, loamy soil I suggest that you make sure that you regularly apply an organic mulch around your shrubs. Over time a regular application of mulch will improve your clay soil, conserve moisture and reduce the likilihood that the soil dries out between waterings.
On an ongoing basis you should fertilize the shrubs in the spring with a slow release fertilizer.
They should be pruned in late winter or early spring to prevent them from becoming leggy. As quick fire hydrangeas are a variety of hydrangea panticulata which blossom on new growth, your shrubs should be pruned before growth begins in the spring. In pruning you should remove any dead branches, cut the shrubs to the desired size and take the opportunity to promote a pleasing shape. Prune back to fat flower buds. Old or thin shoots should be cut down to ground level.
Toronto Master Gardeners get many questions about hydrangeas. Below is a link to one that contains useful information regarding pruning: https://www.torontomastergardeners.ca/askagardener/hydrangea-blooming-growing-pruning/