Climbers...what can I say? Clearly most of you out there agree with my thought that climbers are hard. I'll share a few experiences and observations, but first I'd like to address a few questions about when you prune different roses. What's the best time to prune the Teas and Chinas, for instance, given that in climates where they thrive, they are likely to grow and bloom year round.
The Evergreen Roses—Teas and Chinas
Teas and Chinas have been very happy in my garden. Winter temperatures often drop to below freezing, and sometimes dip into the mid twenties for several days. Not a very cold climate, but near the breaking point on occasion for this group of nearly evergreen roses. In the early 1990s we experienced 100-year lows. The ground froze an inch or so down, and temperatures remained below freezing for several days. At the end, the Teas had no damaged tip growth, except for very soft new shoots. But after a week or so I noticed that the middle growth, canes that were more than a year old, but not gray and barky, had turned black. I've never been able to explain this, but it resulted in die-back of about half of the growth on the Teas. The Chinas were much tougher, perhaps because they were lower to the ground, and the Teas much taller. After cutting out all of the damaged wood, the Teas rebounded and never looked back.
What I do find about the Teas is that because they try to grow, even in the colder part of the winter, and do not lose their foliage completely, they seem to resent being pruned too early in the winter. Once cold sets in, they don't put on new growth until the air warms up somewhat in February. I have pruned them in December and early January, and those years I do experience more susceptibility to bacterial disease, particularly water-mold bacteria which can affect the roots.
I've found that waiting until the weather begins to warm, and pruning the Teas then, or even after they begin to leaf out seems to yield better results. This exact timing will vary by climate; the warmer your winter, the earlier you might time the pruning for. What I look for is to leave the canopy of foliage and slowed or halted growth through mid winter. The Teas can photosynthesize better through the winter, store energy, fend off disease, and tap their feet waiting for spring. Then, when I begin to prune the Teas and Chinas are ready to begin growing, so they don't sit a long time in a completely dormant state.
I have pruned the Teas sometimes after they have already put on 3 to 4 inches of new growth, in late March, and they seem quite happy, and respond by simply putting on more new shoots lower down on the canes that are now exposed to more sunlight. I suspect that in very mild winter climates this is what folks are doing anyway as the Teas will have bloomed right through the winter. Because I time my open garden for the month of May, this very late pruning has the distinct advantage of shifting the first full bloom of the Teas into early May. Unpruned Teas, or those pruned earlier in the winter, would tend to peak for me normally in late April.
As you follow my progress on the map of my garden, you'll notice that I will arrive at the end with the garden of Old European Roses left to the end of the pruning season. This is in part because they take such a long time to prune, when I do prune them. It is also because many of the old classes, Gallicas, Mosses, Albas, Hybrid Chinas and Hybrid Bourbons, experience a real dormancy from which they are slow to break, even in a milder climate. Damasks and Centifolias actually begin to grow quite early in the season, though they may not reach full bloom much sooner than the others.
This late start to growth allows me to get in to prune the bushes later than I might be able to prune a Hybrid Tea or a Tea. Even when they begin to leaf out it is a slower process, so I am able to see into the plants that are not yet completely obscured by their new foliage. Similarly the repeat blooming old classes, Bourbons, Portlands and Hybrid Perpetuals are slower to break into leaf that Teas and HTs. Hybrid Teas, oddly enough are the first to break into new growth in my garden, beating out the Teas by a couple of weeks. Hence, I begin with HTs and Floribundas, move on to the Teas and Chinas, continue with the reblooming old roses, and finish with the old Europeans.
One troublesome element in this handy rule of thumb are climbing roses. While they do vary in when they start to grow by type, Climbing Teas & Hybrid Teas first, Ramblers later, once they have begun to grow, it is almost too late to prune them without causing lots of damage. Canes that must be untangled and re-arranged may lose most of these tender new shoots with all the jostling about. I keep a close eye on them, and when I see buds beginning to swell, I'll drop all of the bush rose pruning and just concentrate on them.
Climbers don't need to be pruned every year, or at least not so completely. And, of course, recalling our first rule, that we only prune for our sakes, not for the roses, the need is an aesthetic stricture. When my arbors produce 6 to 8 feet of new growth over the tops of their roofs, I'm not pleased with the outcome; squashing their structures and reversing the proportions that I find attractive.
In the photo above, Juan and I are working on a 10' x 10' x 10' arbor, an entrance to the old rose garden. The rose is Long John Silver (which may in fact be Iceland Queen), a hybrid of Rosa setigera. It's a very vigorous grower that sends out 15 foot long canes in all directions during the summer. It would quickly knock the arbor right over if we did not diminish the growth each winter. This and other rambers pose the very simplest of pruning tasks. We can simply cut out all of the older shoots, or most of them, and train in the new long canes onto the structure. These newer, unbranched shoots will make thousands of flowers. Smaller climbing roses, especially those that rebloom like climbing Floribundas and Tea-Noisettes produce long canes that will settle into years of productivity, so I keep much of the old growth, but remove the very oldest each year to make way for new canes. Trying to extricate older canes that are embedded in the mass of the plant is much more challenging.
I'll talk more about climbers, and hope to offer a little slide-show of a climbing rose or two, from start to finish in the process. Keep pruning!