QUESTION: I have five plants that I’ve been told are ‘Mini Penny’ hydrangeas. Last year they had lots of white blooms. This year they are growing very well with lots of green leaves etc, but only very few (3) blooms. I have fertilized with an acid balanced Miracle Grow fertilizer as well as a root stimulator. Can you suggest any reason for the lack of blooms this year? – George Carr
First, let’s consider the hydrangea variety that goes by the name ‘Mini Penny.’ A Web search shows that it’s one of the French hydrangeas, a compact, slow-growing mophead variety that blooms pink if the soil is alkaline, or powder blue in acid soil. You say yours had white blooms, so perhaps it’s something else.
Still, we can talk in general about why hydrangeas don’t bloom. The hydrangea expert Judith King, who runs the Web site hydrangeashydrangeas.com (I referred to this site a couple of weeks ago, writing about ‘Annabelle’ hydrangeas), says there are three common reasons why mopheads fail to bloom. 1) If a late spring freeze kills the developing buds, which grow on last year’s stems; 2) If you pruned the shrub too late last year, cutting off the stems that held this year’s buds; 3) If you have a variety that is not suited for this area.
This year, a late spring freeze is probably not the problem. It was cool in late spring, but we didn’t get a freeze, and I’ve seen some gorgeous hydrangeas blooming in gardens around town.
Did you prune? Buds for the following year start forming on French hydrangeas in the summer, so if you pruned the shrub in late summer or fall, you may have cut off all but a few (3) buds.
The third reason – the plant is not suited for the area – can’t be considered until you know what variety you have.
One more note about fertilizer: King advises using a balanced product such as10-10-10, applying it once or twice during the summer. Use caution and follow the package directions, because too much fertilizer can damage the shrubs. It’s also best to fertilize before August, she says, so that any new growth has a chance to harden before winter. Remember, too, that too much nitrogen can cause a plant to grow lots of greenery, but does little to aid in flowering.