How and when to prune a climbing rose

"I live in Chicago, and planted a Climbing Peace rose (bareroot) two springs ago. I feed it a coupla times per summer and trim it down to about 2' in fall. It's put out nice long canes but never a bloom. Have never seen signs of disease or critter infestation. Our soil is very alkaline but I try to balance it with coffee grounds. Help??"

That's a question I was asked recently when I took part in a Monitor webcast with the paper's editor, John Yemma, to talk about gardening. Several questions were submitted via the Monitor's Facebook page.

And because pruning climbing roses is something that's often done wrong – and at the wrong time – I'd like to elaborate here in print on the answer I gave in the webcast.

When and how to prune climbing and rambler roses can differ from when and how you prune hybrid tea and shrub roses.

First, the "when."

In most parts of the country, you should prune rosebushes about the time forsythia blooms. Why not in fall? Because cold weather is on its way, and that can more easily harm canes that are freshly pruned.

You prune hybrid tea climbers – such as Climbing Peace – at the same time. But be aware that not all climbing roses are hybrid teas – roses that bloom repeatedly.

Old-fashioned climbing roses –- and most ramblers – flower only once a year – usually in late spring or early summer. That's why they're always pruned right after they finish blooming.

After all, if you pruned them in early spring, you'd cut off all the flower buds.

My advice? If you don't know whether a climbing rose blooms once or several times a year, wait and do any needed pruning after it finishes blooming the first time.

Then, if it reblooms that summer, you can schedule future prunings in early spring. If it doesn't, prune only after it has flowered.

What you want pruning to accomplish

Another difference in pruning rosebushes and climbers is the reason we do it. There are some similarities, but more differences.

By the end of the growing season, a rosebush is a mess of wildly crossing branches, numerous branches, and too many small canes. Not only does this look messy, but it isn't going to produce the best roses, or as many of them as you'd like.

So you trim out the deadwood, cut away crossing canes, and remove those that are the diameter of a pencil or less. Then you cut the canes back moderately so they will grow well.

You want to encourage strong growth because, in the case of hybrid tea and most shrub roses, that means more roses because rose blossoms are produced on what gardeners call new wood (canes that grow this season).

The bottom line: We prune and keep rosebushes at the best size for best growth.

But the whole idea of climbers is that we want them to cover a certain area. That's why we plant them where we do: along a rail fence, next to an arbor or a trellis.

If we cut them back to two feet tall each spring, they would never grow as tall as we want. Also, the plant would never grow the long canes that earn it it the name "climber."

Prune new climbers very lightly

So, in the beginning, we prune climbing roses less than rosebushes. The only pruning I do to a new climbing rose -- for the first two or three years it's in my yard -- is to deadhead it during the growing season and to cut out any deadwood in early spring.

Also -- this is very important -- I remove all new growth that comes out below the bud union (that's the knobby area near the base of the plant). Then, as the climber grows, I train it where I want it to go.

Beginning in its fourth year, I trim the climber annually to keep it in bounds and from growing too long.

Here are good instructions and videos on the pruning climbing roses, as well as other kids of roses, at Fine Gardening's website. And here's a YouTube video. If you prefer written advice, click here for an excellent tutorial.

Now, it's true that many ramblers and some old-fashioned climbing roses can be overly vigorous and need cutting back to 3 feet high each year once they've become mature. Otherwise, they'll take over. But don't worry about that with a new rose.

Something else to keep in mind, the University of Nebraska Extension Service notes: "Some varieties of climbing roses, often identified by the word ‘climbing’ in front of the variety name, originated as a tall sport from a hybrid rose variety, such as ‘Climbing Peace’. These roses should not be pruned back heavily within the first two or three years after planting, or they may revert to the bush growth form."

How often to fertilize roses

As to the reader's comment about fertilizing roses, I'd feed more than twice a season. Roses are big eaters.

Generally, you want to fertilize them in spring and then lightly each time the bush or climber has finished blooming (to encourage a new flush of flowers).

In Chicago, stop fertilizing by the end of July or first of August. That allows the canes to harden off for winter.

Soil pH and coffee grounds

Will coffee grounds help alkaline soil become acidic? Maybe. I've read differing opinions. If you have them, they probably won't hurt.

Roses prefer a pH of 6.5 to 6.8, which is slightly acidic. Some roses won't mind a pH up to 7.5. What to watch out for is chlorosis, when the leaves turn yellow (especially if the veins are a darker green). That indicates you have a problem with pH. Spray the leaves and soil around the plant with chelated iron.

So I hope this expanded answer helps our reader in Chicago and anyone else who has wondered about pruning and caring for climbing roses.

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