Rose Pruning is easy!
Why do we make kids do word problems in math? Or those odd reading comprehension exercises? One of the important lessons is weeding out extraneous information to get to the point (some people never learn this).
I’ve always liked the "…. For Dummies" book series, because there is a tacit acknowledgment that the reader, while interested in the subject, has no background knowledge and doesn’t already speak the jargon. Much gardening advice comes cluttered with big words and assumptions about your knowledge, often cloaked in the odd 19th century writing style garden writers adopt. "These floriferous specimens are not unworthy of consideration by the discerning plant enthusiast…." (Read: they flower a lot; you might like these!).
Roses, being the most popular garden flowers by far, have more than their share of this, so there is a perception that pruning is complicated. Bosh! Rose pruning is simple. And here’s an important point: rose plants are very forgiving. If you prune them ‘wrong’ you might get fewer blossoms (at first), but you won’t kill the plant.
Here’s a summary. The jargon is highlighted for further explanation.
• When: prune when dormant between mid-Dec. and early Feb.
• Tools: Hand pruners, loppers, narrow saw, coated gloves.
• Remove dead stuff.
• Cut off suckers.
• Open the center.
• Remove all except 4 - 6 canes.
• Cut these back about by half, more or less.
• Cut to a bud pointing outside, about 1/4" above the bud.
• Remove and rake up remaining leaves.
• Apply dormant spray. (optional)
• Dab light colored sealer (Elmer's Glue!) on end of each cane. (optional)
Dormant means the rose is not actively growing. Roses don’t get the message here to drop their leaves, and they continue putting out buds and flowers into December. New buds start to push and grow in February, but that isn’t too late. It just gets harder to see what you’re doing, and delays the first bloom.
My pruning tools are a good, newly sharpened pair of bypass pruners (the kind that cut like scissors–I prefer Felco brand) and a narrow folding pruning saw. A keyhole saw also works. The idea is that the bushes can be dense and hard to get into, so a narrow blade is helpful. Loppers are long-handled pruners. I use them first, just to ‘lop’ off the top growth and get it out of the way. Gloves that are coated with nitrile resist thorns. Some gardeners use a reciprocating saw (SawzAll) for removing old, dead wood–rose wood is surprisingly hard.
Suckers are vigorous shoots that sprout from below the graft. These are a different kind of rose and will overgrow the desirable top part of the plant. If they are coming from below ground, dig the soil away a bit so you can cut them off from the root or stem. Sometimes I get fed up with a plant that is constantly suckering and give it one good pruning: with a shovel.
To open the center we take out crossing branches, twiggy stuff– anything cluttering the inside of the bush. The purpose is to allow more light and air into the bush, reducing diseases.
Canes are the strong stems or branches on which the most common roses (Hybrid Teas and Grandifloras, specifically) flower. New canes are red, old canes are grey. Old wood is more prone to borers and diseases, so we want to remove old ones and leave new ones. A healthy rose is putting out a few new canes each year, so we are choosing the biggest ones and removing the rest. The best ones to leave are those which encourage that open form.
Some types of roses don’t have obvious canes. Don’t worry about it; just thin out the twiggy stuff and cut the plant back about 50%. Landscape and shrub roses don’t even have to be pruned except to remove dead wood.
How far you cut these back will determine the size and abundance of your spring bloom. Cut ‘em to 18" from the ground and you’ll get fewer blooms, but they’ll be bigger and have longer stems. Leave ‘em 30" or more and you’ll have more blooms on shorter stems. The plant doesn’t care either way!
Rather than worry about how far back I’m cutting, I usually cut to a bud (the swelling thing that’s starting to grow, found at the base of a leaf or where one was) which is well positioned (more of that 19th century prose…). The bud will grow in the direction that it is pointed. To enhance that open growth habit (again, to reduce leaf diseases), look for one pointing outwards. On the other hand, if your roses are along a walk cut to one that is pointing to the side or away from the path!
There are four fungus diseases that attack rose foliage, and they overwinter on the leaves. Reducing those diseases is one of the primary goals of pruning. Pick off all the remaining leaves if you have the patience and rake up the ones on the ground. That cleanup helps a great deal in reducing reinfection in the spring. Spraying the bushes with a fungicide containing copper or sulfur creates a barrier on the stems and new growth which blocks the reinfecting spores. Helpful, but not essential.
I never used to recommend sealing the ends of the cut canes. The old black pruning sealants are harmful, absorbing heat (because of their color) and trapping moisture. But sometimes you find hollow canes that appear to have died back. These are inhabited by cane-nesting wasps or carpenter bees. The damage they do is slight, but the moisture trapped in the cane can lead to dieback. So daubing on some light-colored sealant can block their entry. Elmer’s glue just happens to come in a handy applicator, and does the job nicely.
Pruning of climbing roses which bloom all spring and summer follows the same general principles: cut out dead stuff, remove the oldest canes if you can, and shorten the plant. We just cut them back roughly to the support on which they are growing.
A few types of climbers (and some old-fashioned roses) bloom only on last year’s growth (‘old wood’). So when you prune these in the winter, you're removing next spring's flowers! It won’t hurt them, but it kind of defeats the purpose for which you’re growing them! Wait until after that bloom is done, and then cut these back as severely as you wish in the late spring. Rose experts can help you figure out what kind you have from a description, a blossom, or a picture.
One to two cups of Alfalfa meal and a couple of tablespoons of epsom salts are often applied as a last step. The alfalfa meal contains a small amount of nitrogen, as well as plant hormones which stimulate the growth of new canes. Epsom salts, obtainable at pharmacies or garden shops, are just magnesium sulfate. The magnesium helps make the leaves greener and healthier, and the sulfate reduces the soil pH–both helpful in our area.
Don’t be scared–pruning is simple in concept. As with children, we are correcting faults and encouraging them with a little loving discipline. They have thorns, and you have pruners, so this is one case where you CAN say "this is going to hurt me more than it’s going to hurt you!"