TLDR
- Sharpen your pruners (seriously, sharpen them… it makes a huge difference)
- Prune at the right times
- Cut damaged, diseased, or undesired canes
- Remove cut material
SHARPEN YOUR PRUNERS
This was something that took me some time to figure out. I would get out my sharpening stone and give my pruners a few touch up passes and call it good. This was not good enough. I did not know this until a member of the Fort Vancouver Rose Society gave me a Swiss iSTOR sharpener. In the same time it took me to sharpen my pruners with the sharpening stone, the iSTOR sharpener performed roughly 5x better. The blade was SHARP!!! When I was done removing the tiny burrs, I went outside and gave a couple of test cuts on a rose plant and it was like taking a warm butter knife to butter. Do yourself a favor and get one of these.
PRUNE AT THE RIGHT TIMES
You do not want to cut your rose plants too far back in fall. Cutting to about mid-thigh high (knee high for you taller folks) in fall will leave you some room to further cut back any stems that experienced winter damage, disease or overwintered pests. In our area we do the first cut usually in the first weeks of November. It is important that you follow-up this pruning in the very early spring as there may be pests that are overwintering inside of the rose canes. If you see any cane swelling at odd points or what looks like someone took a drill to the tip of a rose cane, cut that out as there are likely larvae that will come out in the spring and begin eating your roses ferociously. Further any winter damage you see will need to be cut out as this will help the plant focus its energy reserves on growing new, healthy canes in the coming year. We typically do our final pruning in the first two weeks of March depending on how full the yard debris bin gets.
WHAT DO I CUT?
The image below from University of New Hampshire shows what a proper cut of a rose bush should be. In the image you can see the cut is performed at an angle. There is much debate about whether this angular cut is beneficial or not. If your pruners are sharp enough, it won’t matter because it will leave a very nice, clean cut that will allow the plant to heal quickly. Prune out crossing canes or canes that heavily fill in towards the middle of the plant as that can limit the amount of air that moves through the plant and increase the odds of rust or blackspot.
If you see canes that are black, take those canes down as far back until you start seeing healthy (no dark ring in the center of the cut flesh) tissue again. This may require you to take the cane all the way down to the bud union. That’s okay. The plant is likely to grow back healthy new canes from the bud union.
REMOVE THE CUT MATERIAL
Typically, if it is a normal rose cane with no overwintering critters or significant disease on it, it is okay to throw that cane on the ground until you can make room in your yard debris bin. That said, if you suspect ANY critters are overwintering, save yourself the later heartache and get rid of those canes as fast as you can. Sawfly larvae is what I have experience dealing with so far and they are fast, sneaky and voracious eaters when in large numbers.