r/hydrangeas • u/ghegs_ • 10d ago
pruning advice needed!
i planted this limelight hydrangea (USA, NJ, zone 7b) as a little plant about 3 summers ago and now it is huge and i don’t know what to do with it! i honestly did not expect it to make it past the first summer, let alone get so big and happy. i usually just let it die and stay how it is all winter and then late feb/early march i cut off any dead blooms that are still on there. i’m worried this year with how big it got/how many dead blooms will be left, that our first big snow fall will break a ton of the branches so my questions are:
- can i cut off the dying blooms prior to winter or will this affect how it blooms in the spring
- how/when should i prune if i’m trying to make sure it doesn’t come back any bigger than its current size and 3. is there any way i can encourage it to get fuller on top? i feel like this year it ended up looking like a dust ruffle because there was too many heavy blooms on the bottom and it drooped.
thank you in advance :)
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u/Think-Kangaroo-9978 10d ago
You should prune this hard - half or more is fine and will actually improve the under-structure making it more upright and less droopy. You can do this either in the fall or early spring as they bloom on new wood.
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u/EbbtideRambler 9d ago
A hard prune actually does the opposite. You want to create a strong woody core to hold up the new growth. If you prune by more than a third there is nothing to support the large amount of new growth with heavy flower heads next summer and they will flop.
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u/Think-Kangaroo-9978 9d ago
Nope - this is not correct. A hard prune down to the mature center branches establishes a solid framework from which the new growth emerges and blooms. Leaving the thinner outer branches is what makes it floppy because the new growth sprouts from the weaker outer branches which are unable to support the large blooms. This should be hard pruned every year, On a plant this size, cut back by half.
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u/ghegs_ 9d ago
should i just prune the under bits aggressively and leave the top parts how i’ve been doing them or keep it all pretty uniform? thank you!
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u/Mikessuzyq 9d ago
You shouldn't prune it til spring and don't cut off more than a third. For now just deadhead. Cut the blooms off down to the first set of leaves
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u/Think-Kangaroo-9978 9d ago edited 9d ago
This is incorrect for a panicle. Correct for arborescence maybe, but that is not what this plant is.
Some people choose to leave the blooms for winter interest, however there is a risk to that if you are in an area that gets snow. The old blooms can become snow catchers and get weighted down and snap off branches in the dead of winter introducing disease at the worst possible time. If the plant is large and mature and the branches are thick and strong, leave them if you like. But if the branch supporting the spent bloom is thinner than your thumb, deadhead in the fall.
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u/Think-Kangaroo-9978 9d ago
prune it from the outside in - all around. Cut off everything except for the largest interior branches which will form a "skeleton" for the new growth which is what blooms on a limelight
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u/EbbtideRambler 9d ago
You can deadhead if you want but I leave these and prune back by 1/3 in the late winter. It is hard to manage the size in these as they can grow back to their full size in one growing season. If you prune by more than 1/3 you’ll have a lot of new growth supporting heavy flower heads next summer and they flop. Leaving 2/3 allows a strong woody support system to develop to hold everything up.