Pruning an Oakleaf Hydrangea

I have two Oakleaf Hydrangeas - not sure what type since the former owner planted them before we bought the house. I need to trim them back some as they are now about 4' tall & almost as wide so they are growing over the daylilies in the bed. I'm looking for some tips about how to safely do this as I don't want to harm, or even worse, kill them...I think I should tackle this in the early spring while they are still dormant but would appreciate some guidance (i.e. when to start, how much to take off, etc). Thank you for the help & if this has been explained before, sorry I didn't find the thread. Jill

Some Oafleaf hydrangeas tend to get very large so finding out the variety's name and age would be useful. It would give you an idea of how much bigger the shrub will get. Alice, for example, can get to 10x10 while PeeWee can get to 3x3 in 10 years.

Oakleafs bloom on old wood. Their Spring 2010 flower buds begin to develop in July/August so it is recommended that pruning happen after they bloom but before July/August. The assumption there is that you do not want to prune and loose any blooms when you do that.

If that case with you, wait until the shrubs have bloomed next year and then prune. If you do not care about next year's blooms then either prune now (there is a chance you might still get a few stray blooms) or do it while the plant is dormant (the chances of bloomage go down markedly).

There is no science to pruning. Just cut stems that cross, stems that are already dead or stems that just do not look right to you. You can prune anywhere along the length of the stem. fyi: most flower buds develop near the end of the stems.

Another suggestion... consider transplanting to another location where the plant can grow and its size at maturity will not matter.

For more information on pruning, see Pruning: Method ONe in http://www.hydrangeashydrangeas.com/pruning.html

Luis

Luis, my "Alice" oak leaf hydrangeas began blooming in mid-July and are still going strong. The blooms hang on for a very long time--into the fall. How do I know when it's OK to do some pruning?

Hello, CapeCodGardener. If you prune after blooming started but before the month of July then you should be fine. Of course, who wants to get blooms on week one and then prune almost right after bloomage starts? The problem is that the date when flower buds develop is a moving target, different every year and is a function of weather, fertilizers, hydrangea variety, etc. You also cannot see the flower buds at first so oh-welllll.

In the South, flower buds begin to form around mid-July. I learned that the hard way when a friend pruned off my hydrangeas in mid-July. I had told her in March to do that but, I forgot about the impact when I said it. The next year, I had just two blooms. As you move further north, flower buds will form later. Around TN, flower buds may start about two weeks later and in the norther states you may start developing flower buds 4 weeks later. Again, it varies.

In your wonderful Cape Code, flower buds probably form approximately 4 weeks later than mine or later. Because there is no clear cut date, it may worth investigating precisely when y-o-u-r average date of flower buds development is.

You can experiment with 4-8 blooming stems located in out of the way places to get an idea. Prune one stem on week 1, another on week 2 and so forth. Always prune on the same day of the week and always "mark" the stem somehow. This identifying mark can then be used in June of next year when the shrub blooms again. I use colored plastic bands and I write entries/notes either in my Outlook Calendar Month of June 2010 or on a wall calendar. That way I know what each colored band meant in June 2010. For example, a single yellow band might have represented a stem pruned on Sunday August 9, red was a stem pruned on Sunday August 16, two yellow bands was a stem pruned on Sunday August 23, orange was the next week etc. You can also use those little colored wire thingies on bread/buns packages.

In June 2010, when the plant is blooming again, check the stems to see which ones did not bloom. Then check the notes to see when those were pruned. The stem(s) that does not produce blooms in 2010 will be identified and this will give you a good way to tell how far out you can prune and still get blooms. Just remember that whatever date you come up with, it may change + or - two weeks in future years. Also remember that other hydrangea varieties may not develop flower buds at the same time as this Alice. To make sure that you can find the stems in June 2010, take pictures with a digital camera for reference purposes.

If all you are interested is in deadheading though, you can deadhead at any time.

I hope you enjoy your Alice. I had one myself but freakish El Nino weather patterns in Texas 2-3 years ago produced so much rain from March thru July that it died. The spot is now too sunny so I have no oakleafs at this moment. Do you have other oakleafs? How old is yours? How tall has it gotten? My Alice that died probably would have had to be transplanted. When I bought it, I was told it would not get big,,, I think they said 4-6' only but hmmm, we have a very long growing season so I was starting to think that maybe 8-10' would have been more accurrate.

Luis

Thank you so much, Luis, for your detailed and very helpful pruning advice for my beloved Alice Oak-leafs. Both of mine are are about 3-4 years old and sized about 3 1/2 by 3 1/2 feet. One has 15 and one has 10 blooms, which are just beginning to turn slightly pinkish-brown. They are somewhat rangy (lopsided) in form, which is why I'm interested in pruning them, at least somewhat. I'm happy that they made it through our winter with flower buds intact after I moved them from a more sheltered, but out-of-the way location last fall to their present part/sun setting in my front yard.
According to your estimation of Cape Cod flower-bud formation, mid-August might be when flower buds are forming. I just went out and peered at the growing tips; all I can see are small leaves beginning to form. Will I recognize flower buds eventually?

Thanks for the advice! I am not sure what I'll do - probably wait til after they bloom next year & be more on the ball! I had no idea that hydrangeas could get as big as your describe!

Good question, about when buds are visible but I must be getting old.... I have not been able to remember to look for buds in Spring so I cannot tell when they become visible. Maybe someone else can chime in. :o(

JGinTN, some hydrangeas will get big but not all. It pays to looks at the label when you buy. Paniculatas can get tall as trees so some people in the NE grow them as trees from one single upright stem. When I go visiting relatives in MA/NH, I see lots of them out there. Of course, pruning will keep paniculatas (and all others) in check if you do it every few years. I have seen some awesome pictures of a hedge of Limelight Paniculatas that were kept probably arounf 6' tall (just a guess). And shorter ones using mopheads.

For more information on pruning, see Method One in http://www.hydrangeashydrangeas.com/pruning.html

Luis