Updated: Apr 17, 2022
Canadian gardeners for the most part are a very resilient bunch. Couped up all winter staring at the drifts of snow and the rabbit tracks going from one shrub to the other with little brown organic presents (Easter Bunny dropping off free fertilizer) we can hardly wait to get outside and feel the sun on our backs and the soil beneath our fingernails. As soon as the lawn dry's up firm we get our 1st calluses from raking and cleaning up all the refuse that's been lying under the snow. Then we turn our attention to what to pruning? The time to prune any woody plant is after it flowers so if it flowers in spring you prune in summer (i.e. Forsythia, Serviceberry), if it flowers from mid-summer to fall you prune in spring (ie Hydrangea, Spirea, Potentilla) Evergreens and broadleafs flower in late spring so their pruning takes place mid-June. I will be creating a blog on that topic.
Hydrangea sp. in Ontario comes in an abundance of varieties and colours. There 4 main groups (species categories) that classify them separately in habit and hardiness.
Hydrangea arborescens: these are the snowball flowering types with Annabelle being the Queen of the crop with new variations arriving all the time. This category produces flowers on new growth so prune them down to within a few inches of the ground much like most perennials. One little trick you might try to create more flowers albeit a little smaller is to pinch the tips out after the foliage has flushed approx. 1' in height, this will delay the flowering but provide a much more floriferous show of some-what smaller blooms that stand up better to the rain as the larger they are the harder they fall.
Hydrangea macrophylla species flower on old wood so you only remove old blooms and weak and deadwood. Many of the new varieties now boast repeat-flowering with1st blooms on old wood and then a second flurry of flowers on the new growth, giving the appearance of endless summer flowering. These tend to be less hardy in harsher exposure and many never repeat-flowering at all....so buyer beware!
Then come my favourites the Hydrangea paniculata species, larger more upright with large pinate or conical flowers on new growth. Nurseries now boast 15 varieties of breeding dwarf habits, white, pink, and red, and some dinner plate flowers. The King of the Hydrangeas is Limelight, a sturdy upright with lime green blooms starting mid-season, turning to white for an extended time the as nighttime temperatures cool they tint to pink and after frost hold tan-coloured cones that sequester snow and provide the most bang-for-buck of any flowering shrub I know
Since our property has an abundance(44 at last count) of Hydrangea I will demonstrate with some established plants. Here is a sample of our Limelights.
Here is a row of 15 Limelight Hydrangea 7 years established in this raised bed as the foundation garden for our humble abode. The 1st time I pruned these my wife was on the verge of divorce, as she "exclaimed you're killing my Hydrangea's!!
Surprisingly since we have been married since 1976 and I have been pruning and teaching pruning classes for almost 40 years, but this time she took notice. I told her to calm down and be patient and the Hydrangeas returned to their glory and we are still married. Now Every April 1st she doesn't ask (she demands) if its time to prune the Hydrangeas and she can hardly wait until I am back out there with pruners in hand and wheelbarrows of brush go to the fire pit. As you can see we leave the blooms on all winter long and they only start to disintegrate with spring thaw.
1st I remove all dead, broken, weak branches, then all branches that point inwards.
Now comes the part that is crucial, look at last year's growth and where it branches off of the previous years growth and count 3-5 buds (swollen little bumps) and cut on a slight angle just above the bud(node) with the last or end bud facing away from the shrub. Think of Antlers and you will come to grips with it.
Each plant's branches will look like Deer antlers, be sure that you leave the last bud on each branch facing away from the plant or facing the ground, not inside or facing up as that would encourage growth inwards. New growth comes from every bud and they will fill in accordingly. Next will be cutting back all the grasses.
Upon the 1st week of May, the first buds break out from the dormant buds
1st week of June the foliage is filling in nicely.
1st week of August and everyone is slowing down as they drive by, its a show-stopper every year.
Seeing is believing
As evening temperatures begin to cool in September a light pink tinge enhances the entranceway and foundation
As you can see on the top right of this picture the Limelight Hydrangea enmass. I will add pictures throughout the season so you can see how amazing this variety performs and developes. FYI three generations of Cavan gals collecting windfall apples for homemade apple sauce.