Hydrangeas

October 2012

I enjoy your weekly column and have followed your advice on many occasions. I have a hydrangea bush that I planted in the bed near the front entrance of my house, however, now that it has grown it is about to overpower the entrance. When is it safe to move the bush, can I safely cut the bush back now?

Hydrangeas are not the most winter hardy plants, so I would not move it now. Wait until the end of winter or early spring to move it. Also, flower buds are already set now for next summer, so no pruning even when you do move it in late February through mid March. I am a bit concerned about some hydrangeas. Many have been putting on new growth with our mild, moist weather this fall, and some have even bloomed. I hope they have a chance to harden off and be prepared for winter, but time will tell.

October 2012

When should oakleaf hydrangeas by pruned, and how do I do it?

Oakleaf hydrangeas and the bigleaf hydrangeas (those with the pink and blue flowers) both bloom in the summer, but set flower buds in the fall. It is too late to prune them now until next summer. The only time you can prune without damaging flower set is immediately after flowering. Oakleaf hydrangeas begin with bright white flowers, which fade to a dusty rose and then tan. If they need pruning, as soon as the white blooms begin to fade, begin pruning. They are cane producing plants, which means you should thin them at the base, removing older, woodier stalks. If you plant them where they have ample room to grow, you don’t need to prune as often.

July 2012

I have a ten year old hydrangea that I have never pruned. It used to bloom beautifully at the top, but this year, most of the blooms were at the bottom. When should I prune and how? Do I need to cut off the old flowers as they fade?

If you are planning on pruning your hydrangea, you need to do it soon. Hydrangeas bloom in the summer, but turn around and set flower buds for next year in the late summer or early fall. Remove up to one third of the older canes at the soil line—this should reduce the size, but still leave plenty of growth for blooms for next year. As to removing the spent flowers, that is a personal preference. Some gardeners like the look of the dried flowers, while others think it looks bad. Do continue to water, since hydrangeas are not drought tolerant plants.

June 2012

I live in Bella Vista, Arkansas and I have a question about my hydrangeas. They were absolutely huge and loaded with blue flowers this year — I use coffee grounds on all my acid loving plants and they thrive. This year I had about 60-75 flowers and we got a big rain. All the flower heads were bowed over. Now I have a lot of bent branches. I know they set their flower buds on last year’s growth, so if I prune all the bent branches, I probably won’t have any flowers next year. I would have to cut about two feet off of each branch to get to straight limbs. Any suggestions on what to do?

Actually, the time to prune hydrangeas is immediately after they bloom. Instead of just cutting two feet off, try thinning the plants out and remove up to 1/3 of the limbs at the soil line. Cutting hydrangeas at the tops of the stems will encourage branching. Each branch on the stalk can produce the large flower heads which can make them top-heavy and not able to support the blooms. Pruning now will allow the plant to recover and you should still have flower buds set this fall for a bloom for next summer. Hard, cold winters often take a toll in the NW part of our state, but our lack of winter this year has given us quite the hydrangea show this year.

March 2012

I have some hydrangea bushes that are 5-6 years old that have never bloomed!! Unknowingly I cut them down the first year thinking that was what you did with the “sticks” that were left but after I was told NOT to do that I haven’t done it since. They set buds on the old stems like they are supposed to but even with fertilizing, they never set one bloom! Is there ever a time when you DO cut back the old stems or do you just leave them to continue to grow and grow from year to year? And what suggestions do you have which might help them to bloom?

Many people make the same mistake, since hydrangeas do look like dead sticks all winter. Thus far, they have made it through the winter this year unscathed! The top buds on those “dead sticks” are the largest flowers in the summer, so if Mother Nature freezes them back, and all your new growth begins at the base, we won’t have blooms, which was very common last year. Remember, they do need some sunlight to set flowers—so if yours are in total shade, that could be limiting flowering too. Have a reason to prune—too large, etc. If your plant does need to be pruned to maintain size, do so as the flowers start to fade in mid-summer. Just like the above forsythia, hydrangeas are cane producing plants, so remove older, larger canes at the soil line to encourage new canes and reduce size.

March 2010

Can (or should) Rose of Sharon bushes, gardenia bushes and/or mock orange bushes be pruned and if so, when is the best time to do it?

When pruning any plant there are three questions you need to ask before grabbing the pruning shears: why, when and how? Why do they need to be pruned—have they overgrown their space, do you need a specific shape or size, or has there been any damage to them. Once it has been determined that you need to prune, then know when is the best time. If they are spring bloomers, like mock orange (Philadelphus coronarius), then all pruning should be done AFTER they bloom. Spring blooming plants set flower buds at the end of the growing season. Pruning as soon after flowering will give them ample time to recover before they need to set more flower buds. If your plant blooms in the summer, like the Rose of Sharon (Hibiscus syriacus) they bloom on the new growth and should be pruned before growth begins—in late February until mid March. Pruning later simply delays the first set of flowers. As with all things there are exceptions to these rules—Gardenia or cape jasmine (Gardenia jasminoides) and big leaf hydrangea (Hydrangea macrophylla) and oak leaf hydrangea (H. quercifolia) bloom in the summer but set flower buds in the fall. Some newer cultivars of gardenia and hydrangea ‘Frost Proof’ gardenia and ‘Endless Summer’ hydrangea actually set flower buds in the fall but also set some flowers on the current season growth. Choosing a plant that fits the location will limit how much it needs to be pruned. If pruning of gardenias or hydrangeas are needed, do so immediately after the first big flush of flowers in the summer.

September 2009

My hydrangeas around my patio have grown too large. I am not sure what kind there are, and understand that different hydrangeas are pruned at different times. When and how can I cut them back to make them more manageable, yet still have flowers?

There are actually several varieties of hydrangeas grown in Arkansas. The most common is Hydrangea macrophylla—the big pink or blue types. These plants set flower buds in the fall before going dormant, and then bloom on these buds the following summer. Pruning should only be done immediately after flowering in the summer. Some of the newer cultivars like ‘Endless Summer’ and ‘Blushing Bride’ actually bloom on both old and new wood, so if they get winter damaged, you still have some summer time blooms, but prune them like other macrophylla types, after the first flush of flowers. The Oakleaf hydrangea- Hydrangea quercifolia has the same bloom pattern, with summer flowers from buds set the previous season. They typically don’t overgrow their bounds and are lovely in partial shade or a woodland garden, but if pruning is needed, do so as the white flowers begin fading to brown. The two types that do bloom on the new growth are H. arborescens –the smooth hydrangea and the Panicle or Peegee Hydrangea- H. paniculata. They both produce white flowers on the new growth, and as such, could be pruned as much or as little as needed before new growth begins. Since hydrangeas are cane producing plants, it is often best to reduce height and size by removing older, woodier canes at the soil line.

July 2006

I live in Northwest Arkansas and have some Nikko Blue Hydrangea bushes on the North side of my house that receives only morning sun. Should these be pruned and if so how and when is the best time to do this?

Nikko blue is a type of Hydrangea macrophylla --or big leaf hydrangea. It blooms in the summer--usually June, and sets new flower buds in late summer to early fall. If it is overgrown and needs pruning, it should be pruned as soon as the flowers start to fade. Take out one to three of the older canes at the soil line. If there is room for plant growth, and the plant is healthy, you don't need to worry about pruning, but don't delay too long after bloom if it does need pruning. Be aware that big leaf hydrangeas can be winter damaged in Northwest Arkansas. If all of your growth occurs from the soil line each spring, it was frozen back by a late freeze and you won't have any flowers--but huge bushes. A lot of our more northern gardeners are opting for hydrangeas that bloom on the current season growth such as Annabelle or Endless Summer to solve the problem.

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