When is the best time and how do you prune?
Every Hydrangea species is different, and each cultivar of each of the species can be different. You have to do a little research into what kind of hydrangea you have and whether that individual cultivar flowers on old wood (from last year’s growth) or on new wood (this season’s growth). Some plants, especially newer cultivars, will bloom on old AND new wood.
For Hydrangea Macrophylla (big-leafed Hydrangea for shady areas), if the plant blooms on new wood, you would cut the plant back hard (within a couple of inches from the ground) while it’s dormant in winter or early spring. The plant will grow back and bloom as it should.
If the plant blooms on old wood, it is best to prune after it flowers in the spring or summer. On these plants, you would prune to shape, not cut it back near the ground.
Again, there are hundreds of hydrangeas across three main trade species and each one is different, so know your plant and go from there. As far as how to prune, hand pruners would give you the best cut, or shears would work if the plant’s stems are smaller.
When is the best time of year to divide?
As a grower and landscaper, I have never divided hydrangea and wouldn’t try it. All Hydrangea species are woody shrubs and most woody shrubs can NOT be divided. This is because most woody shrubs only have one or maybe a few stems.
It is possible, over time, that a mature Hydrangea (species macrophylla) with many stems could be divided by digging the whole plant up, cleaning off all the soil, and gently pulling apart any stems that have roots connect to them. Then replant each small section and care for it (watering, fertilizer, etc.) until it is established.
Most people take cuttings – that’s how they’re propagated in the trade. If someone is going to try a division, do it in the early spring when the plant is still dormant. This will give the divisions plenty of time to establish before the heat. Late fall is also possible, but losses in the winter are likely to be higher.
Pruning and caring for hydrangeas can get a bit complicated if you want to get it right. If you have a more specific questions about this or anything else in your garden, let us know in the comments below or on our Facebook page. We’d love to help you make your garden one of Kansas City’s best!