How do I Prune Climbing Roses?

For any number of reasons still partially unknown to us, the genes of the rose change to create a genetic mutation (or "sport") of a "normal" rose, and thus it sends out a longer cane. This mutation can occur either on a rose that produces blooms several times a year (called "repeat bloomers"), or it can occur on roses that produce blooms only once a year (called "once bloomers"). By selectively propagating and cultivating these sports, we create a climbing rose. Sometimes this mutation is deliberately hybridized rather than voluntarily appearing in order to purposefully create a climbing version of a particular rose.

Climbing roses are best thought of as a "garden form" much like a prostrate (or "groundcover") rose. If you will think of them in these terms rather than as a variety or Class, then the problem of pruning becomes much easier to understand. Because a climbing rose doesn't have any mechanism of its own with which to hold onto something (like Boston Ivy or Passion Vine, for example), it really doesn't "climb" on anything. If left to its own desires, a climbing rose would just sprawl out into the landscape. Therefore, by thinking of a climbing rose as a garden form, our real concern is how to maintain its shape, keep it growing where we want it to grow, and force it to maximize its bloom.

True climbing roses do not bloom on the main canes. Rather, they bloom from "bloom stems" that emerge from the main canes or from secondary stems (called "laterals") growing out from these main canes. Both the main canes and the laterals are growth that has occurred during previous seasons. (Ergo, we frequently use the old saw, "Climbing roses bloom on last year's wood.") The length of the bloom stems growing out from these canes and laterals is determined by which type ("Class") of rose we are growing. Hybrid Tea climbers produce very large blooms on long bloom stems, for example. Conversely, Species and Polyantha climbers produce small or medium sized blooms in multiple clusters on very short bloom stems.

The question then becomes how do we prune to maximize our bloom stems and thus maintain our garden form? And when do we do this to maximize our bloom?

When the climbing rose is first planted, it is best to let it remain in the ground and unpruned for the first two or three years. Except for the removal of "dead wood" do not prune anything. Let the rose develop its long main canes. Then select 4 - 6 large canes growing in the direction you want them to grow, and prune out the rest. Prune them all the way to the ground. This is best done in the very early spring or late winter while the rose is still dormant.

For the main canes that remain, think of them as the scaffolds or the body frame for the main plant. (I like to imagine them as the ribs on a Japanese hand-held fan, and I perform my pruning with this garden form in mind.) If we prune back the "scaffolding," we automatically prune away some of the laterals (those secondary stems) along with it. And because we prune away the laterals, we also prune away the potential for bloom stems. (My "fan" will be smaller and it will have fewer "pictures" on it.) Consequently, we don't want to prune the "scaffolding" (the main canes) unless they are very old, dead, diseased or they just plain "get in the way." If the "scaffolding" must be pruned (see note below), it can be done whenever you need to do that. But if you are pruning during the growth season or in zones where roses do not experience a dormant period, I recommend you cover the cut with a sealer like orange shellac or Elmer's Glue-All (not School Glue or Carpenter's Glue). This will prevent borers and other pathogens from invading your rose until it has time to seal its own wound.

Note: If the main canes become very old and "barky," they tend to quit producing good bloom stem growth and should be removed. Take out the oldest canes all the way to the ground (or grafting union), and try to leave at least 4 - 6 canes to support your laterals and bloom stems. This should be decided in the late winter or very early spring when you're out pruning your other roses.

On Hybrid Tea climbing roses, we prune the laterals way back -- close to the main cane, but not closer than two leaf nodes from the main cane. A leaf node is that pimply-looking, tiny bump on the stem. It is from this node that the bloom stem and foliage will emerge. The reason we prune this far back is because the subsequent stem that emerges can be no larger in diameter than the stem from which it grows. We want our Hybrid Tea blooms to be on long, sturdy bloom stems. So we prune our laterals back as far as we safely can so that the emerging bloom stem will grow as large as it can. What you end up with after your pruning is several long "sticks" spread out with lots of little 4-inch long "sticks" growing out of them.

When do we do this pruning of Climbing Hybrid Teas? When you would normally prune your other, shrub-form roses. For me, that's generally late winter/very early spring -- just as the nodes are beginning to swell and we can tell whether we have any dieback from the winter.

On climbing roses that bloom in clusters (which include most of the other climbing roses), we don't prune back the laterals quite so drastically (although you can do this if you want to maintain that particular form). In fact, we frequently just clean up the twiggy growth and prune the laterals back to the garden form we want. This may even allow a few tertiary stems to remain on the lateral. The bloom stems will emerge from the nodes on these secondary and tertiary stems. But because the bloom stems are shorter and smaller in diameter than those of the Hybrid Tea and because there are so many blooms, we need the extra support these secondary and tertiary stems will provide.

When do we prune these types of roses? It depends on which type (or Class) of rose you have and whether it will repeat bloom for you.

For Climbing Grandifloras, Climbing Floribundas and repeat-blooming Large Flowered Climbers (those roses that will repeat their bloom or remain in continuous bloom), we prune when we normally prune our shrub-form roses - again, late winter or very early spring.

For Ramblers, Species, once-blooming Large Flowered Climbers, and other once-blooming roses (like many of the old European roses), we prune after the main flush of bloom in the spring. Depending on where you live and what variety or Class of rose you have, that could be as late as June or July. The reason we wait until after the flush to prune is because we want as many roses as possible. The more secondary and tertiary stems we have, the more bloom stems will be produced, and hence the more blooms will be produced. You can still perform a late winter/early spring "prune out" of the twiggy growth because this won't produce many (if any) blooms. But if the stems are larger around than a No. 2 lead pencil (say, 1/4 in. or 6 mm in diameter), then my technique is to let them remain on these types of roses.