It’s finally time to prune your big leaf and mountain hydrangeas. This is in addition to what I wrote in January about hydrangea pruning. At that time I wrote that it was safe to go out and prune your woodland/smooth hydrangeas and your panicle hydrangeas. If you haven’t already done that, get going unless you live in the milder parts of the country where you are long past your deadline for this task. Here is an excellent video from Bloomin’ Easy that might be a good refresher for you when it comes to pruning your panicle hydrangeas: https://vimeo.com/251842660
Now for hydrangea pruning of big leaf (macrophylla) and mountain (serrata) varieties.
The Emergence of “Broccoli” in Hydrangea Pruning
Without seeing “broccoli,” it would be foolish to prune old wood plants. Just this past week, “broccoli” has finally emerged on both these varieties. The same goes for my climbing hydrangeas (anomala petiolaris) and oak leaf (quercifolia) hydrangeas. All flower on old wood, and some (the rebloomers) flower on new wood they will grow this year. They all seem to have made it through the ups and downs of my zone 5B winter. But is it safe for me to prune them?
THE RIGHT TIME FOR HYDRANGEA PRUNING OF BIG LEAF AND MOUNTAIN PLANTS
To decide that, the last piece of info I needed was the long range weather forecast. According to my local meteorologists, there are no expected sub-freezing temps. That timing takes me past my average last frost date which is my green light. Time to get going on pruning big leaf and mountain hydrangeas, as well as other old and new wood plants in this family. The reason I needed to wait is that if I removed – even just deadheaded – rebloomers prematurely, I would have stimulated their “sleeping buds” to initiate growth. Those new growth/buds could have been zapped by a late season freeze. So now I am assured that the buds I see as well as new buds that I will stimulate will not be affected by cold temps. Of course, I still need a forgiving summer to get the later season flowers from my rebloomers. The best I can do for them is fertilize and irrigate properly as the season progresses.
Exactly What To Do
Pruning your big leaf and mountain hydrangeas can be as simple as deadheading all the old flowers. Period. But you might also take the time to remove any diseased, damaged, and dead wood. Consider going further down the plant – carefully – to remove the leftover dead stubs from prior year’s cuts,
as well as any branches you see crossing or rubbing with another. I would also encourage you to remove any stems thinner than a pencil as they will not produce a flower and will rob your plant of the energy it needs for the stronger stems.
Once you have made all your cuts, take the time to fertilize your plants with a granular shrub fertilizer that is labeled for shrubs. Rose fertilize is ideal.
Stay away from 10-10-10 as no plant uses nutrients in the same amounts and all those products do is contribute to pollution and runoff. You could also add compost but don’t think it is a substitute for fertilizer.
Check the Irrigation
Inspect your irrigation if you have it. Soaker hoses should be laid a few inches from the base of the plant and ideally buried under a layer of mulch. Speaking of mulch, check that it is at least 2 inches deep all around and doesn’t touch the base of your plant.
And that’s it! Your plants will thank you for this care and feeding. And you will enjoy the rewards of your efforts.
UPCOMING SPEAKING DATE
With Covid restrictions easing, I am thrilled to be back in front of a live audience. On Sunday, May 16 at 11 a.m. (YIKES!! That’s next Sunday!) I will be speaking about hydrangeas at the Southeastern CT Home and Garden Show. This show is being held at EARTH EXPO & CONVENTION CENTER AT MOHEGAN SUN, 1 Mohegan Sun Blvd, Uncasville, CT 06382 (Click for DIRECTIONS). The daily entry fees are: $10 Adults, $8 seniors, 12 and under FREE. More info on this 2 ½ day event is at:
I’ll also be selling signed copies of my internationally best selling hydrangea book, Success With Hydrangeas. So tell/bring your friends. I would love to meet you – finally!!
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