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What is the science?

User
10 years ago

Being obsessive compulsive, I moved two roses during the Thanksgiving break. Both are grafted, one on multiflora and the other on Dr. Huey. I cut each back, watered them well, buried the grafts deep and mounded them slightly.

I know that the conventional wisdom is that I should not have done it and should wait until around pruning time in late winter/early spring. However, I cannot see to figure out the science behind this. Both roses should be in dormancy by now as we have had about two weeks of below 30 night temperature here. When I dug them out, the ground was frozen to about 2 inches.

I do see that exposed canes might suffer and dry out in the winter wind and that a comprised root system might affect the canes' water intake. I can also see this might be the nail on the coffin if the rose is borderline hardy in my area or diseased.

So what is the science for not moving roses in early and mid-winter, assuming that they are fully cold hardy and generally healthy?


Thanks

Comments (12)

  • mad_gallica (z5 Eastern NY)
    10 years ago

    Absolutely no reason not to. The issue is that many 'hardy' roses aren't really. And to be honest, the big reason not to move HTs in the fall is that you may be wasting your time digging up a rose that is going to die over the winter anyway. If you move it in spring, at least you know it's alive.

    There are a lot of things I would and have done with Explorers without thinking twice that I'd never dream of doing with an HT.

  • Campanula UK Z8
    10 years ago

    blank look! We (in the UK) always move roses during autumn and winter, whether planting a bare-root, transferring from pots to soil, simply moving a grown rose - everything is done suring winter dormancy - traditionally, from November through to March. Autumn is prime planting time as also when we divide many of those early flowering perennials.....so, unless I have misread the OP or misunderstood.......
    Generally the soil retains residual warmth for many weeks so although top growth may well stop or slow down, root development and expansion continues apace without any pressures from transpiration or evaporation or the requirement to push top growth - an ideal time for establishing bare-root trees and shrubs and planting bulbs.

  • michaelg
    10 years ago

    If there is a warm spell and the plant starts growing, canker infection is possible. I had trouble with new bare-roots planted at this time, and that seems a similar situation.

  • henry_kuska
    10 years ago

    Perhaps this Pickering suggestion may be useful:

    "Planting with insufficient or no protection. At planting time the roses should be mounded up with soil, leaving only the branch tips sticking out. Fall planted roses should be left over winter this way. In spring a newly planted rose is best treated the same way to
    prevent the branches from drying out in the sun and wind; after two weeks the mound should be removed."

    http://www.pickeringnurseries.com/plantinginstr.pdf

    Here is a link that might be useful: Pickering link

  • User
    Original Author
    10 years ago

    Thank you everyone, for the response.

    Michael -- do you think the reason for increased canker infection is due to "bruises/injuries" to the rose canes when they are being moved? For example, if the thorn gets broken off, the rose won't have the chance to heal, which would be conducive to canker infection? Intuitively, this makes perfect sense to me.

    Henry -- thanks for the tip! I will cut mine further down and mound a bit higher.

  • User
    Original Author
    10 years ago

    Also, I think that mad-gallica's point on HTs probably goes a long way in terms of explaining why many people avoid moving roses in winter. As a newbie, I have been educating myself about roses by reading whatever I can get my hands on. My impression is that a lot of the existing sources are heavily colored by people' experience with HTs. A good example is the pruning tips one get from various online sources, which more often than not treat all roses as if they were all HTs.

  • roseblush1
    10 years ago

    farmerduck ....

    I am not a scientist or an expert, but one of the reasons HTs and many modern roses of other classes are not moved in winter is that they are not truly dormant.

    The genes which brought the repeat flowering characteristic into the rose gene pool also brought the genes which made the rose plant incapable of going fully dormant. These roses store their nutrients in their canes rather than in the root zone as do ogrs. When transplanting, most people cut back the top growth to be the same size as the root ball. When you do this to a modern rose, you are, in a sense, robbing the plant of the nutrients it requires to get through the winter and push into spring.

    Studies have shown that the roots of some roses will grow in temps of -15F, but that always depends on the rose.

    The reason I would never transplant a rose in winter is that it is too dang cold outside to be digging holes and planting roses. That's not science. It's just personal preference ... lol.

    Smiles,
    Lyn

  • mad_gallica (z5 Eastern NY)
    10 years ago

    Well, I certainly wouldn't mound them. IME, that kills a lot more roses around here than any cold. Mike Lowe used to recommend putting a rose cone with the top cut out around fall planted roses. That gives a bit of wind protection without any of the rot associated with having material against the canes.

    The weather forecast here for the next two days is a high of around 50F, and rain.

  • michaelg
    10 years ago

    In New Jersey, I would be concerned as much about too much warmth as too much cold. I have topped unruly roses around Dec. 1 and had the pruning cuts develop botrytis canker that ran some distance down the canes. I have planted new bare-roots at about the same time and had them make new growth that froze, rotted, and caused canker that in some cases spread down to the graft. If the temperature never rises above 40, though, you will have neither growth nor microbial activity.

    I have successfully transplanted roses at this time, but it is safer to wait until spring.

  • roseblush1
    10 years ago

    Michaelg..........

    I think your warning about possible disease from topping or what I call "snow-tipping" roses may be climate specific. I've snow-tipped a few of my roses every year for the last nine years and had no disease issues.

    You cannot say that my climate is low humidity in the winter months. We can get anywhere from 25 to 50 inches of rain starting in late October to, or through, April with periodic snows at my elevation.

    However, I did take your warning about wet organic material near the base of the rose being a possible source of disease seriously. For the first time since I have gardened here, I've had to deal with leaf litter from my neighbor's trees. The neighbor above me removed all of his pine trees and left just the oaks and cedars to make his property more fire safe. The neighbor next to me also removed four trees. It seems like all of the leaves from their trees blew into my garden and landed at the base of my roses.

    I've spent the last four weeks, with far too many interruptions, crawling under my roses and removing leaf debris from under the roses and using tongs to pull the leaves out of the plants.

    The roses where I had made collars in previous years to hold the usual mulch back, were the easiest to clean up.

    Thanks for the heads-up.

    Smiles,
    Lyn

  • michaelg
    10 years ago

    Lyn,

    This is how I interpreted my bad experience with early-winter topping: the plants were semi-dormant and so didn't have their immune systems active, but it was just warm enough that botrytis fungus (my guess as to what it was) could germinate and spread. It started in the cut cane ends and ran a foot or so down the canes, blackening the bark. It wasn't a big deal because I would have pruned that much off in spring anyway, but it scared me away from the practice. (I might do it again only if a heavy ice storm impends.) If I had pruned severely instead of topping, I might have lost some plants in this episode.

    As you say, the conditions that led to the problem are not going to occur everywhere and often.

  • seil zone 6b MI
    10 years ago

    Personally I don't plant or move anything in the fall or winter. I wait for early spring. I've had very bad luck with them dieing over winter when I did try it. For some reason they don't seem to settle in very well and never come back in the spring. Don't ask me to give you a scientific explanation because I can't. I just know from my own experience that it has never worked for me. Fall planting is money wasted for me.

    I don't prune anything in the fall either. We bounce back and forth from warm to cold for a long period of time. For example, today the high is 55, veritably balmy, Saturday our high will be 26. It's been back and forth like this for weeks now. Every time it gets too warm for a few days they try to grow which isn't a good idea because then the temps drop again suddenly and that new growth is toast. I want them to store energy not use it on useless growth the will surely die off. Pruning them makes them want to grow even more so I just don't do it.

    I think some of you are HT-aphobic, lol. I have dozens of them, both in pots and in the ground, and they winter very well. The pots do get protection but none of the ones in the ground get any protection at all. Many of them are green to the tips come spring. They're like any other class of roses. Some of them are quite hardy and some of them are tender. Not even all OGRs and shurb roses are winter hardy. The trick is to find the ones that are hardy for you and that takes time and trial and error. I could tell you what winters easily for me but it might not in your yard. And what winters blissfully for you may croak it's first winter in mine.