Barbara: If you live in coastal Southern California it’s time to prune your roses. Pruning shapes the plants and encourages healthy new growth by forcing a kind of dormancy on them. Since we don’t have the cold temperatures to put our roses to “sleep”, we have to make them take a rest by pruning them and clipping off any remaining leaves.
Pruning should be done between January 1st and February 15th. Any sooner and there’s a danger that frost could harm new growth that might occur during warm spells. Prune later than mid-February and you’ll impact the new growth that starts when the soil warms up. (Bioactivity in the soil and new plant growth get going when the soil warms to about 50 degrees.)
The very first thing you should do is make sure your tools are sharp and clean. You’ll need some loppers for the bigger canes, a pair of hand pruners (bypass, not anvil which tend to crush rather than cut) and a good pair of gloves, the longer the better. You might also need a small handsaw if you have some really old, big canes.
The general idea is to remove weak, or dead canes and crossing branches. Remaining canes should be the thickest ones and you shouldn’t cut more than one-third of the growth. Canes can be left fairly long, up to four feet, if they are healthy and you have the space for it. The finished bush should look like an open vase. For those of you who need a visual — hold your hand palm up and hold your fingers as if you were going to pick a large piece of fruit. That’s what your rose bush should look like when you’re done.
- Start by identifying the healthiest, thickest canes – at least four or five, more is ok. You’ll keep these.
- Remove dead and diseased canes, cutting back to where they grow from the bud union — that knobby part just above the soil line at the base of the plant.
- Remove any canes that cross over or rub against other canes that you are keeping.
- Remove weak, spindly canes to the point of origin. Remaining canes should be at least a pencil’s thickness.
- Remove any suckers that are growing from under the bud union.
- Shorten the plant by about one-third, cutting the cane at a slight angle 1/4 inch above an outward facing budeye — the small nub that which you will find just above a leaf. You can cut as much as one-half the height off, but the plant will have to put a lot of energy into growing new wood. You’ll get less blooms, later in the season as a result.
- Clip off ALL remaining leaves from the plant and rake clean the surrounding beds. A thorough cleaning will help prevent diseases.
- It’s a good idea to spray with a dormant spray. Check with your local nursery for their recommendation and follow the directions to prevent harm to beneficial insects.
When you are done hybrid teas should be at least 2 – 3 feet tall. Grandifloras should be around 4 feet tall. For floribundas you can leave some of the twiggy growth; the plant should be at least knee-high and have a rounded shape.
You don’t need to seal the cuts. The rose cane borer is not active during our pruning season and the cuts will heal before they emerge. If you must, use white glue or anything not tar-based. Tar-based products can harm the plants.
Mulch with a good organic compost. Fertilization should wait until new growth is at least three inches, usually in mid to late-March.
Update: I was pruning my client’s roses today (Friday) and thought I should mention that if your roses are still very leafy you’ll probably want to snip off some leaves first so you can see what you are doing. Not recommending blind pruning – never a good idea.
Next week: More rose pruning. We’ll talk about how to prune Old Garden Roses, shrub roses, tree roses and climbers. And round-about March, Mary Beth will do a post on rose pruning for climates that have hard freezes.