What’s up with clematis and hydrangeas that won’t bloom?
A Q&A with garden writer Ciscoe Morris on a clematis variety that looks healthy but has never bloomed, and on hydrangeas that bloomed for a year or two but then stopped.
Special to The Seattle Times
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In the Garden
Q: I have been perplexed for many years concerning my clematis. The variety is ‘Gipsy Queen’ and it is healthy but never blooms. Every spring, I prune it back a couple of inches from its base, which I also do to the two other ‘Gipsy Queens’ that bloom beautifully. Any ideas why the one doesn’t bloom?
A: I’m fairly sure the clematis that doesn’t bloom was mislabeled. ‘Gipsy Queen’ features large velvet-purple flowers from June to September. Since the flowers are produced on current season’s growth, the vines can be cut to the ground in late fall or spring without interfering with blooming.
On the other hand, many varieties of clematis bloom on previous season’s growth. A good example is C. ‘Nelly Moser,’ an extremely popular variety with 9-inch pink blossoms with a deep pink stripe on each petal. The blooms on ‘Nelly Moser’ are produced in May on growth that occurred the previous season. Therefore if you prune the vines down to near the ground, it will remove the wood that produces the spring blossoms, and there will be no blooms the following season.
The easiest way to find out if the clematis was mislabeled is to forego pruning of the suspect clematis next spring. If it blooms in May, the mystery will be solved. If you like the flowers enough to keep it, from now on, rather than pruning hard in spring, give the vines a light pruning in late February or early March, removing a few crowded vines, while cutting the remaining ones to varying lengths to create a well-balanced framework of vines.
As long as you preserve plenty of the vines that grew the previous summer, you’ll enjoy abundant flowering every spring.
Q: We planted two hydrangeas eight to 10 years ago on the west side of our house. They bloomed for the first year or two, but not since. Every summer they fill out with healthy leaves. They get full sun from about noon until sunset. Any reason they aren’t blooming?
A: There are two main reasons why hydrangeas don’t bloom. Either you’re pruning too hard, or your hydrangea isn’t hardy enough for your climate. Although there are exceptions, most mop-head and lace-cap hydrangeas bloom only on growth that occurred the previous season. Hence if these branches are removed, or killed by cold, there will be no flowers that season.
If you prune your hydrangeas back by a third or more to control for height, you’re removing the previous season’s wood that produces the bloom. Rather than cutting back hard every spring, thin your hydrangea by symmetrically removing about a third of the canes by cutting them to the ground or where they come off another stem near the ground.
Prune the remaining branches down only one or two buds from the top. Your hydrangea will be taller, but it will have an open, elegant appearance and since this method preserves previous season wood, it should bloom beautifully in mid- to late summer.
If you haven’t been pruning your hydrangeas back hard, then it is likely that your variety isn’t cold hardy enough to produce in your climate. If a hydrangea is too tender for the area it is growing in, winter cold either kills the growth that occurred the previous season outright, or simply kills the buds that would have produced flowering branches. Either way, the plant typically survives and grows back healthy and strong, but fails to produce any flowers.
If you suspect your hydrangea isn’t hardy enough for your climate, give the plant to a friend who lives in a warmer area. Your nursery expert should be able to recommend plenty of varieties that will reliably produce spectacular flowers where you live.
Ciscoe Morris: firstname.lastname@example.org “Gardening With Ciscoe” airs at 10 a.m. Saturdays on KING 5.
About Ciscoe Morris
Ciscoe Morris' column runs Thursdays. His show "Gardening with Ciscoe" airs at 10 a.m. on Saturdays on King 5.