Thank you for sharing your question about pruning Hydrangea.
Here is what you asked:
"1-2 years ago someone hacked back the plant and it grew back with a vengeance. Can we cut it anymore this season, or would you just leave it alone"?
Let me just begin by saying that pruning Hydrangea is not a must, and yes you can just leave it alone, the Hydrangea shrub can definitely survive without our passion for pruning. On the other hand, (the hand that holds the shears...) you can use your pruning skill (and you are certainly skilled) to encourage new growth and bloom.
O.k then, let's prune!
So, you're going to prune that magnificent hydrangea with the aim of encouraging new growth and preventing a potential brake - as the branches get heavier there is a risk of them breaking. As you can see in the picture below, I've only marked the bent branches, those growing outside of the imaginary 'frame' of the plant.
Why? well, it's early spring, the weather is just getting warmer and the hydrangea looks great. The only thing you want to achieve at this point is a rich looking shrub that will hold throughout the season.
Prune like I showed you in the picture, just a very gentle hair cut and you should be fine. There is no reason what-so-ever, considering the conditions I was mentioned, to prune any harder.
In the long version, further down the page, I'll explain what, where and how - so you can plan your next pruning cycle.
When to prune? The three cycles:
1. Late winter or early spring - prune and remove the top of the plant leaving only 20 inches or so growing above the ground. This will encourage rich new bloom and will keep the shrub tight with strong branches.
2. Mid-fall - or even a little earlier. This will allow the shrub to enter the winter dormancy after growing new leaves.
3. Throughout the season - this is maintenance pruning and includes removing the dead and dried flowers just above the highest node. You can also prune and remove branches that are trying to escape the 'frame' you have created.
Where to prune? See the red line... that's more or less the height you should prune your hydrangeas at next season (late winter or very early spring). Now, when you make the cut try to look for the node and prune just above it, not too close to the node. Looking for and finding nodes on Hydrangeas is easy. Hydrangea stems have a unique structure and where the nodes are the stem looks like it's swelling. Just to make sure you understand the meaning of node - these are soon to be leaves.
Tip: If you wish to get larger flowers, you can cut the shrub close to the ground, but only in late winter or very early spring. That means below the red line - i mean real low.
Maintenance pruning - Remove dead branches during winter, a bit like roses, the skeleton is naked and you can see right inside the shrub. Recognizing the dead branches is easy as well, their color will be different and if you're not sure whether it's a dead or a live branch use your shear blade to scrap the stems surface, If it's green inside - It's alive!
I hope that was helpful!
Of course there is a whole bunch more things I can say on the subject, but I think this will get you started...if you have more Q's, please feel free to send them over.
Providing general guidelines on 'how to prune' any kind of plant is important, but there are plants, and there is YOUR plant. So despite there being loads of information on this site, I also provide specific and personalized support. If something wasn't clear, or you're not sure of your plant's name, simply send me a picture with your question. Use the form below and I'll get back to you. In the mean time, see what others are asking.