encouraging repeat bloomers to go dormant?

I planted a number of roses this spring, and I’m wondering if I can encourage them to think about going dormant. Last fall, even though we had some frosts, my roses kept growing and even trying to bloom until mid November when it suddenly got down below 20 degrees for extended periods. I think that was hard on them, even though I had soil mounded the plants. It seemed like the growth above the soil was too tender and died back, and the part of the plant that was covered with dirt got moldy and rotted when I uncovered it this spring. Most of the plants did survive, but I wanted to do better with them this year. My native species rose is turning red and obviously thinking “It’s fall, winter is coming, time to lay low,” but the others that I planted are still blooming and putting up new growth.

Can I prune off the new growth and buds rather severely to encourage them to put energy into the roots, or will that just make them try harder to put out more new growth?

Will ceasing to water them make them go dormant, or will it just stress them too severely and make them more likely to die out over winter?

Do you have any other suggestions?

Thank you,

Ruth Wiechmann

South Dakota (theoretically zone 4)

Ruth,

You didn’t say what varieties you’d planted, but it sounds as though they are tender and would feel more at home in Zone 7 than Zone 4 (or maybe Zone 3–you said “theoretically”).

Definitely don’t prune off new growth late in the season–you’ll lose the new growth you prune off, and then you’ll lose the new growth the plant puts up in response to your pruning. Double whammy.

It sounds as though you may be putting on winter protection too early. Usually winter protection shouldn’t be applied until the plant has had a chance to get thoroughly cooled (perhaps several hard freezes into the low 20s) and the soil has begun to get cold. Winter protection is intended to keep the plant from getting too cold, but it’s also intended to keep the plant from getting too warm too early in the spring.

Do stop feeding the roses after July. If you have varieties that set hips, leave the hips that form after the first summer bloom cycle. The formation of seeds sends a slow-down signal to the plant.

Your roses survived, so you won the first battle, but with those kinds of roses it will be a battle every year. To make the battle less strenuous and worrisome, look around for whatever help nature can give you. If you have several places where you can grow the plants, look for the area that has the best microclimate for winter and doesn’t warm up really early in the spring. Snow is your roses’ friend, so if you need to move snow from a walkway or other location, you know where to put it. And you may be able to think of some other ways nature can help you.

I’ve emailed you links to 2 sites with fairly good discussion of winter protection tactics.

Peter

Peter,

Thank you for the information. Most of my varieties are supposedly ok for zone 4. I am not sure how accurate the zone ratings really are for me, though, as we have very dry winters, can’t count on snow cover, and also have lots of wind. My intent was to try several varieties from the various classes to see how they would stand up to our weather. I did get a few zone 5 plants to try, but even the centifolias & gallicas are not indicating that they’re thinking fall yet. They are working on putting up some new shoots. My spinossissima (Frulingsgold) is blooming; last year it was still trying to bloom & grow in November. The Morden Blush is also blooming, and those two are both supposed to be zone 3.

Thanks again,

Ruth

As you know, with global warming we’re getting a bit of “zone creep” and the seasons are not always behaving as they should. Was last winter pretty typical for where you live, or did the weather stay warm later than it should have?

Peter

Last winter probably froze up a few weeks later than normal. I think it was November 20th when the ground finally froze. That can happen by mid-late October, and usually around November 1st. We’ve been in a drought cycle for the last six years or so, with very open, warm winters (for us, and very little snow cover. We’re hoping that changes soon, but we’ll see. We had an atypically cool summer this year, with more moisture than we’ve seen in a long time. Everything was two weeks late this spring, and we had snows well into May. We had our first frost about two weeks ago, not unusually early, but earlier than the past few years, and now it’s supposed to get up into the 90’s again this week.