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Garden Experiences: Pruning Roses
Copyright © 1999, 2003, 2004, 2005, 2009 by David E. Ross
(The copyright notice also applies to the rose photographs.)
Prune while the shears are sharp!
From Christmas to New Year, I prune my roses, peach tree, and grapes. Here are my suggestions on rose pruning (more philosophy than technique).
- Time your pruning according to the weather. Do it before new shoots begin to sprout. If you live in a climate such as mine, with mild winters, do it even while your roses are still blooming, in December or January. Often, I cut a small bouquet of roses for my wife while pruning. If your winters are severe, wait until the worst of the freezing is over. But do it before the last frost.
- Read an illustrated pruning book. Either go to the library and borrow one, or go to a bookstore and buy one. Sunset has an excellent all-climate pruning book that also covers other flowering shrubs, fruit and ornamental trees, grapes and other vines, and other woody plants. I have also seen other books that appeared quite good. You need to see diagrams of a well-pruned rose and of proper cuts.
- Make sure your tetanus shot is current. Besides scratches from thorns — not avoidable even with gloves and long sleeves — there is always a risk that you might slip with the shears or saw. And thorns can give deep scratches and even cuts. (I admit it! I don't normally use gloves. They interfere with plucking leaves or dabbing glue.)
- Before you start to cut, take a minute or two to study the plant. Picture how you want it to look in the coming summer. Visualize in your mind how much height is added by new growth. Imagine how the plant might grow out over your lawn or a walkway (very bad if someone walks into thorns). Try to see where symmetry can be created by an judicious cut. Plan.
- Don't force your pruning shears. If a stem is too thick or hard, use lopping shears (pruning shears with very long, heavy handles). For even harder cuts, use a fine-toothed pruning saw. Forcing the shears will both injure the plant and damage the tool.
No, I do not subscribe to any size standard when judging which tool to use. Some thick rose canes may be quite young and succulent, easily cut by hand shears. Other canes the same size may be old and woody, not easily cut even with lopping shears.
- Try to keep new canes and remove old canes. Of course, a well-placed older cane might be better than an awkward newer cane. Don't keep more than five canes on a bush; four are even better. Sometimes, three well-placed young canes can be best. (For climbers, keep a mixture of new and mature canes.)
No, you do not have to remove all side branches from the canes. But do remove all twigs and stunted growth.
If a bush has no new canes, add Epsom salts (magnesium sulfate) to its first feeding of the spring. Use about two tablespoons for a small shrub and a quarter-cup for a larger shrub. The magnesium promotes the growth of new canes. If that does not work, consider replacing the shrub.
- Definitely remove any cane that grows out of the soil or from below the swollen graft union. Such a cane is likely a sucker from the root stock and will not grow true to the variety grafted onto that stock. After a while, a vigorous sucker will dominate the plant and the grafted variety might die out entirely.
- Any cane or branch that you keep should be headed. Heading cuts should be made just above a bud that faces away from the center of the bush. Look carefully; some buds are hard to see. On a thick cane, a bud is the small nub that lurks just above the point where a leaf used to grow. On a thin branch, a bud is much more easily recognized.
- Leave longer canes for those roses that grow vigorously. Keep weakly growing shrubs short. I prune my taller roses to about 2-3 feet and my shorter roses to 1-2 feet. (Climbers are quite a different subject; see below.)
- If you live in a mild-winter climate and your roses are still in leaf when you prune them, pluck all the leaves off (a real bother on a climbing rose with canes 10-15 feet long). In any climate, try to collect all fallen leaves. Rose leaves will harbor pests that will attack in the new growing season, both insects and fungus (especially rust). The leaves on the plants also interfere with obtaining a good coverage when I apply a dormant spray. (This is the only time I force a plant to go dormant. And dormancy is not the goal, only a consequence.)
- Do not put rose trimmings into your compost. The thorns are more durable than wood and will not readily decompose; you risk serious injury working with compost containing rose trimmings. Also, the heat in a home compost pile is often insufficient to kill rust and mildew spores and might not even be sufficient to kill insect eggs.
- Seal every significant cut with white wood-working glue. Any cut made with lopping shears or a pruning saw is significant. I seal any cuts on branches thicker than a soda straw. The glue prevents borers from entering and seems to speed the healing of the cut. Do not use pruning paint, which seems to cause dieback.
Of course, some will argue that cuts do not need to be sealed at all. They cite the fact that, in nature, trees often drop branches; the wounds heal without any attention. First of all, such a wound near the main trunk might instead become the starting point of rot that will cause a tree to become hollow and weak. More important, the context is quite different. Hybrid roses are themselves unnatural; they are not found growing in nature. And when you cut a healthy, vigorous cane to redirect its growth, it is definitely not the same as a dying branch falling out of a tree. Pruning roses is an unnatural activity performed on an unnatural subject. Seal every significant cut.
- Have no regrets. You made a cut, and you — and the rose — must live with it. Unless you removed the graft union, the bush will recover. Indeed, roses (like peaches) seem to thrive after heavy pruning.
- After pruning, I use a dormant spray. This is one of the few times I do any preventive spraying. I use a mixture of an oil spray and a copper spray, with liquid soap added as a wetting agent. The combination helps to prevent fungus and kills over-wintering insects and their eggs.
Yes, I know this is contrary to some gardeners' philosophy of using only natural products and organic methods. However, roses in my garden are hybrids that are not natural plants; and they definitely would not survive in a southern California natural environment. (See my comments on Organic and Natural or Inorganic and Artificial.) In any case, the proper pruning of a rose bush involves an unnatural control of its growth.
- Throughout the year, as you groom your roses and remove faded flowers, consider that as a form on ongoing pruning.
- Don't merely remove an old flower, but make the cut to direct future growth. Sometimes, this might mean cutting away a longer stem than is normally suggested. It always means cutting just above a growth bud that points in the direction you want for new growth.
- A poorly positioned cane with a faded flower at the end may be removed entirely.
- New growth will be more vigorous if at least one leaf is removed along with the faded flower.
- Always seal any significant cut. Borers are most active in the growing season.
- While grooming, remove any dead branches and stunted growth.
Some special considerations apply to climbing roses.
- If you have a climbing rose, you definitely need to be current with your tetanus shots. Climbers seem to have at least twice as many thorns per foot of cane than do shrub roses.
- Do not reduce a climber to a shrub. Leave the canes as long as possible, to the point where their thickness diminishes to that of a pencil. I have a climbing 'Peace' on which I leave the canes 10-15 feet.
- Climbers send flower shoots up from canes that are horizontal. Train your climber to grow along the top of a fence or low wall.
My climbing 'Peace' is planted in front of a slough wall about 2.5 feet high, made of concrete blocks. At about intervals of about 30 inches, I drilled into the top of the concrete blocks, inserted plastic anchors into the holes, and then screwed in large screw-eyes. I tie the canes to the screw-eyes. This means that the canes I keep must be either sufficiently limber to bend without breaking or are mature canes that were trained in the previous growing season. The result is a plant about three feet high and 15-25 wide.
- Keep about two or three canes growing in each direction from the base of the plant. (This means keeping a recommeded total of six canes for a climber instead of the recommended three or four for shrub roses.) At least one cane should be new growth from the previous summer, and one should be a mature growth from the year before that. The new canes will be the most vigorous, but the mature canes might produce the most flowers.
- As you groom a climber during the growing season, again do it as a form on ongoing pruning. In addition to what needs to be done to shrub roses, also —
- Remove some (not all) of the upright flowering branches, cutting back to the horizontal cane from which it grew. The upright side branches you keep should be cut short.
- Tie down new long canes to train them. That way, you reduce the risk of breakage when you try to tie them down during next winter's pruning.
25 December 1999
Last updated 22 September 2009