1. WHEN to prune: The best time to prune most roses in the Bay Area is in January, when they should be dormant. Many of our roses will still be struggling valiantly to bloom, but they actually need the rest, and should be forced to nap against their wills like exhausted toddlers. The exception to the January rule is roses that only bloom once in spring: these should be pruned right after they finish flowering. It’s ok to deadhead and cut back dead or weak canes any time of the year, but avoid serious pruning in November or December: it can encourage tender new growth just in time for a freeze, and will awaken the plants just when they should be dozing off.
2. WHAT you need: Invest in a sharp, comfortable pair of hand clippers and a good, thick pair of thorn-resistant gloves. Wear tough outer clothes that won’t get snagged (never prune in a sweater, especially a bulky hand-knit sweater, says the voice of sad experience). I like to keep a large tip bag or debris can handy for the clippings. Welding masks are optional, unless you’re planning to prune an enormous overgrown viciously thorny three-story high climbing rose. I always keep a pair of Sliver Gripper tweezers in my pocket.
3. WHY you’re pruning: You’ll do a better job if you have a basic understanding of your purpose. First, your mission is to remove any dead, weak, or sickly plant material that can drain energy and carry diseases over to the next season. This means any twigs skinnier than a pencil have to go, and all leftover leaves should be removed. Second, you want to increase airflow to the center of the plant, and open it to more sunlight. Air and sunlight will prevent fungal diseases next spring. Third, on the modern roses, you’re going to remove spent under-wood that will no longer produce flowers, to prevent the plant from becoming leggy at the base.
4. WHEN to prune hard: The modern Hybrid Tea roses and Floribundas will only produce flowers on the next season’s growth, so you’ll want to get rid of all of this year’s growth. Grit your teeth, steel your nerves, hold your breath, and cut these bushes back hard, leaving only about 6” of canes at the base. I know it’s scary at first, but trust me; this will be the best thing you can do for these roses.
5. WHEN to prune lightly: Antique roses, English roses, and many shrub roses don’t thrive on the radical hard pruning that the modern roses need. Large, arching canes that curve gracefully up and over towards the ground should not be butchered. Thin them, and lightly prune the lateral shoots, leaving the main canes intact. Remove canes that crisscross the middle of the plant or rub against another cane.
6. WHEN to skip pruning: Very young roses need time to grow before they get cut back a lot: with all roses except the Hybrid Teas and Floribundas, skip a pruning season, to let them fill out and develop their natural shape. Some of the large, wild ramblers never need to be pruned: ‘Climbing Cecile Brunner’and ’Lady Banks’ are two examples. Some climbers, like ‘Climbing Iceberg’ and ‘Climbing Peace’ bloom only on old wood (last spring’s new growth will be next spring’s old wood), so pruning will prevent spring flowering.
7. HOW to prune climbers: As with arching canes, the natural form of a climber is part of its beauty, so the long canes shouldn’t be shortened or cut back much. All climbers need to be trained, and retrained: make sure the canes don’t go straight up, or flowers will only bloom at the very top. Training a cane away from the vertical, so it grows horizontally or diagonally, breaks the flow of nutrients to the tip and promotes flowering lateral shoots all along the cane. These laterals can be pruned back to two or three nodes. Get rid of any unruly canes that insist on obstructing walkways or threatening innocent bystanders.
8. WHERE to angle the cut: The angle is more critical on some varieties, such as Hybrid Teas, whose canes tend to die back if they’re not properly slanted to shed moisture. Cutting at an exact 45-degree outward angle is an impressive habit to develop, but not a desperate necessity in most cases, so don’t bother with a protractor. The same is true of trying to choose an outward facing bud. The direction of the axillary bud (at the junction of leaf & cane) indicates the direction the new cane will probably grow, and ideally you’d like it growing away from the center. But the Murphy’s Law of Rose Pruning says there will not be an outward facing bud anywhere on the particular cane you’re tackling, and besides, canes are prone to mid-life crises that cause them to suddenly turn in different directions for reasons that elude science. In other words, life is too short to lose much sleep over being exact. Some professional rosarians like to prune with a chain saw.
9. WHAT to remember: Relax and have fun. It’s not as complex or tricky as most of the books make it look. “Pruning a rose bush is not unlike giving a home haircut to a small child; you do the best you can, secure in the knowledge that if it turns out odd-looking, new growth will quickly hide your mistakes…few plants are as forgiving of beginner’s efforts as are roses,” says Liz Druitt in The Organic Rose Garden.