Can you divide a hydrangea? If so, how and if not, why?
Hello, Jeff. I have not tried this but many people have reported success diving them; think of this as if you were transplanting the shrub, except you are transplanting only a portion of it. It works with either plants that were just recently purchased, with old potted hydrangeas or in-the-ground hydrangeas. However, it is easier to divide a potted hydrangea because the soil has not compacted.
Also, consider your timing. It is starting to be late in the season. I would do that in Spring so the plant has ample time to recover from transplant shock or during winter while the plant is dormant.
Obviously, an old hydrangea will have an extensive root system that will be hard to cut. There will also be smaller and fibrous roots in the edges. Try to salvage as much of the root system as you can since this will ensure a good supply of moisture; that includes the smaller fibruous roots.
Mulch well and be prepared to water the rootball area only, until the plant develops new roots in its new location. There may be water issues during its first year; be on the lookout for problems, especially during its first summer.
For a look at what others have done, do a search on the forum; look up the word "divide".
Let me give you my impression of this proposed activity :-))
Generally, woody-based plants (trees and shrubs) do not divide successfully. Most generate from a single stem or trunk and dividing that puts the entire plant at risk. There are exceptions - many species of hydrangeas tend to be caning shrubs or shrubs that produce multiple stems/trunks from the root crown. They may not do so initially as potted nursery plants but will often develop these multiple stems or canes as they mature. If that is the case, they can be divided with great care. Other shrubs - lilacs, forsythia, shrub dogwoods, etc. - also have this type of growth habit and can sometimes be divided. Personally, I find there is far less risk to the mother plant and far greater success if you propagate from cuttings or by layering rather than attempting division.
Thanks to both of you for your comments...
Jeff, I have divided hydrangeas before, though I tend to agree that it's easier to take cuttings. I dug up the entire plant in the cool of fall, washed the soil off the roots as much as possible and than pulled the rooted stems apart very gently. I potted them in good potting soil and kept them watered through the winter. When they started pushing growth in the spring, I set them in the ground. They were not fancy new ones. They were un-named mopheads I had been given as pass alongs in New Orleans. Needless to say, they are extremely heat tolerant, which is why I was willing to go to the trouble. I lost no divisions.
Just yesterday I took out the axe and with a couple of swings I divided three Hydrangeas that I've been using in pots and they were getting too big for the pots. I had three, now I have six.
There was a very woody section right at the base of the plant and I used my snips to open up the soil from the sides and bottom until I got to that hard core of wood and then a couple of whacks with the axe.
I've done it plenty of times.
I lose a couple of the stems in the process, and if I'd had the time I would probably have taken cuttings from these stems. I have taken cuttings from Hydrangeas this time of year and put them away with my other overwintered plants. They didn't put on any root growth over the winter, but by mid summer of the next year I had some well rooted plants.
That way you can have your cake and eat it,too, I guess.