Roses are pruned to encourage new growth and healthy flowers during the growing season. The time to prune roses depends on the type of rose your pruning. Roses that flower once a season are pruned right after they flower. Roses that flower throughout the season are pruned when buds start to swell and become green. In Southern Oregon, Zone 8, this is typically mid- February to early March .
Tools Needed:
1) Good pair of leather gloves,
2) Sharp By-pass garden pruner, (recommended)
3) Possibly: a medium to larger tree pruner and a handheld pruning saw.
Having sharp tools is imperative for making good clean cuts on branches. Also, it’s important to disinfect every tool between each rose, because tools can transfer disease and viruses to other plants if not disinfected properly.
Disinfecting Tools:
1) Isopropyl alcohol (rubbing alcohol) is ideal for sanitizing pruning tools because the blades can be wiped, or dipped into it. Most rubbing alcohols contain 70% isopropyl alcohol, which can be used straight from the bottle. Rubbing alcohol has a strong fumes, so avoid inhaling.
2) A solution made of chlorine bleach can also be used as a disinfectant, but unlike alcohol, bleach must be diluted before using and blades must be soaked for 30 minutes for disinfection to really work. To make a 10% bleach solution: mix one part bleach to nine parts of water. Remember to: avoid inhalation of fumes, wear rubber gloves to prevent contact with skin, and protect your clothing from the bleach and bleach water. This bleach solution must be used within two hours of mixing, because it losses 50% of its effectiveness after two hours. After soaking tools in bleach solution, rinse them with clean water to prevent corrosion, and wipe dry. Be aware that chlorine bleach it is not as effective against viruses as rubbing alcohol.
Steps to Pruning:
1) Start by removing dead and diseased canes; brown is dead, green is alive.
2) Tip back brown stems until you see green in the cane.
3) Remove all thin weak canes; if it’s thinner than a pencil remove it.
4) Open up the center by taking out crossing branches. Branches that rub cause damage and encourage disease.
5) Removing center canes allows air-flow which helps control diseases.
Making the Cut:
Common practice is to make a slight 45-degree angle cut ¼-inch above an outward facing bud. Cutting to an outward facing bud encourages growth away from the center of the rose to provide better air-flow. An angled cut is said to allow moisture to run off the cut. While some rose growers say angled cuts are unnecessary, everyone agrees if the cut is too steep it weakens and/or damages the new bud, so cut at a “slight” angle.
Rose Structure:
The goal is to have an open structure with upward reaching branches in the shape of a vase.
How much top pruning is done depends on the type of rose. Typically, only 1/3 of the total height of a rose should be removed, unless an extremely neglected rose shrub needs hard pruning to reshape and repair. ( See examples of Hard, Moderate, Light Pruning in the drawing below)
Seal Cane Cuts:
Seal cut ends of all canes 3/16-inch diameter and larger with white Elmer’s multi-purpose glue, not school glue, or white water-base Tacky Glue, found in craft stores. This forms a barrier to deter cane boring insects from drilling into the pithy middle of rose canes, where they lay their eggs. In some cases, a boring insect can bore deep enough to kill the entire cane, and sometimes the whole rose bush.
Article By: Carlotta Lucas, Ashland Garden Club Member
Resource Article:
Barbara McMullen
Master Gardener OSU Extension
Drawings from Oregon State University webpage on Pruning Roses. Rose Pruning: https://extension.oregonstate.edu/gardening/flowers-shrubs-trees/pruning-roses
Read more on Rose Borers: https://www.gardeningknowhow.com/ornamental/flowers/roses/controlling-rose-cane-borers.htm