When to Prune Raspberries and Roses

Q. Mary in Cherry Hill (New Jersey) writes: "I have a lovely but overgrown Constance Spry climbing rose that I'd like to really cut back. Right now, it's wild and has broken its support. I want to know if I can cut it back this winter to about 18" from the ground and then train it on a much stronger arbor. What would you suggest? Thanks."

A. Well, thank YOU for bringing up Constance Spry! The famed flower arranger had more accomplishments--nurse, head of the Irish Red Cross, World War II Victory Garden expert, and domestic science instructor, to name a few--than I have fingers and toes. Her shop, "Flower Decoration" was THE go-to-place in the UK for unusual and striking floral decorations; and her name was attached to the very first David Austin rose introduction, thus launching his famous "English Rose" series. The Constance Spry rose is a fragrant double-flowered pink rambler often described as 'lanky'--a term that invites pruning.

Luckily, Mary seems to know that this time of year--Fall--is THE worst time to prune anything. As Constance Spry surely knew, pruning stimulates growth. Pruning in the Fall stimulates growth just as the plant is trying to go dormant, sucking vital energy out of the root system. And with winter weather to be expected at any time, that lush new growth could freeze solid, effectively ending the need for further pruning.

And there's always the risk of a cold, windy winter without good snow cover. Snow is good for plants; it insulates the crown, protecting the plant against wild temperature swings. Without the wonderful natural insulation some gardeners call "God's mulch", the top of the plant is likely to suffer some winter damage from wind and desiccation. Plants that are unpruned going into winter have a lot of biomass to lose without harming the plant long-term. Plants that have been neatly pruned down to six inches or so will join The Choir Invisible; again, avoiding the need for future pruning.

So put those pruners away and don't listen to so-called experts that urge you to 'clean up' your garden in the fall. The only 'cleaning up' you need to do is suck and shred your fall leaves for mulch and compost making.

Back to Constance. The dead of winter--the dormant season--is a perfectly acceptable time to prune things that are not Spring bloomers, but its not the best time. Let's say we cut back this wandering rose in January and one of those freaky winter warm spells arrives and wakes up the rose, followed by freezing cold with no snow cover. The health of this rose is now threatened in a half-dozen different ways. Better to wait until Spring; specifically, about two to three weeks after the rose and your other plants have greened up and all chance of a hard frost is in the rear-view mirror.

And eighteen inches seems a bit dramatic to me. This rose is a Great Dane and trying to turn it into a dachshund isn't going to make anyone happy. I'd leave much more of it standing--at least four feet. Why? This rose only blooms once a year, and you're going to get the most roses if the plant hits the ground running with a good amount of bio-mass. (At least it's only supposed to bloom once a year. I would deadhead the spent flowers promptly and see if we can rewrite that part of the catalog page.)

Then prune it back every other Spring and it should be less destructive--but it will always be a ramblin' rose. Side Note: Roses thrive with a mulch of compost; wood mulches invite diseases to attack.

Q. Lillie in Milwaukee writes: "How and when do I prune my raspberries? They are going crazy!"

A. They're supposed to! Raspberries are like Labs; they can't sit still. Prune only dead wooden canes in late Spring/early Summer next year--NOT before; canes that appear to be dead in the winter might just be dormant and may bear a lot more berries in the Spring.

For most varieties it works like this: New canes sprout in the Spring and grow all season long; six to eight feet of length is normal. At the very end of the growing season, big juicy raspberries will appear at the tips of these canes. Do not prune these first year canes; although you can pull off the spent berry clusters.

The following Spring, new 'green' canes will sprout from the ground. The previous year's canes will green up and clusters of berries will appear all along the length of those canes. This 'second year harvest' is almost always much larger than the previous year. After harvest, second year canes will start to visibly die off, with yellowing leaves and brittle canes evident by mid-summer.

NOW you can prune out those canes at ground level--or as close as you can get. It gives the raspberry patch a much cleaner look and encourages the growth of new canes. Side Note: Never feed a raspberry patch with potent fertilizers; the canes will provide the best harvest in poor soil to which a little compost has been added.