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At what temps. do you worry about the safety of potted roses?

KnoxRose z7
9 years ago

Hello all!

I have lots of roses in various sizes of pots on my front porch (covered porch & on a cement slab shared with my home) and a few more in the back yard, sitting on the driveway not protected in any way. Both locations have a decent amount of sunlight. Since this is my first year with potted roses, I am not sure when I need to move them closer to my house/ put them in the unheated basement/ or if I should provide any protection for them at all. I am in zone 7a, it has just started dipping down into winter temperatures, with the nights staying somewhere right above freezing, and increasingly common frosts, but the days still somewhat warm. I know it is probably early to worry, but I want to make sure I'm not taking any risks.

I know that roses can handle a decent amount of cold, but I just get worried when I see the frost, I just don't know how much cold potted roses can handle, especially young ones. I know several of you have large container gardens or "pot ghettos", I always hear people to refer to them, and it seems as though I have accidentally acquired one myself, what are your winter preparation practices?

Thank you!

Jessica.

Comments (25)

  • susan4952
    9 years ago

    In zone 5 , I start dragging them in after 3 nights of hard frost. Usually after thanksgiving. To a garage that rarely gets below 40. Make sure they are well watered. This includes tree roses. Some are 10 years old. I think in zone 7 u could get away with outdoor shelter and protect with mulch up against the house. You will be pruning the winter damage in the spring, so don't worry too much about that. Think of the roots and graft union.

  • buford
    9 years ago

    I'm in zone 7B, a bit warmer than you. I've had years where I left pots out all winter with no damage. But last year was bad. The day we had the polar vortex, by the time I got home from work, the pots where frozen solid. I was able to get them in the garage and they survived. I think if it gets into the 20s and doesn't warm up during the day, that's when you need to bring them in the garage or some spot warmer than out in the yard.

  • michaelg
    9 years ago

    It's the roots, more than the tops, that you need to worry about with pots in zone 7. Roots of garden plants are protected by the ground heat which normally keeps them above 20. The slab and driveway will transmit some heat to the pot, but not nearly as much as for a garden plant. The size of the pot matters, with small pots being much more vulnerable. For good sized pots, I would not worry until temperatures approach 10 degrees. Pots on the driveway or against the foundation should be OK if you pile leaves around the pots and a little over the rim.

  • hoovb zone 9 sunset 23
    9 years ago

    can you temporarily "plant" the pots in the ground for the winter?

  • Poorbutroserich Susan Nashville
    9 years ago

    Jessica, are you in the far eastern part of TN, mountainous area, or more like Knoxville? I'm in Nashville with a large amount of potted roses. Here are some things I try to keep in mind with my pots:
    The class of rose is important. If it's modern or a Bourbon or an HP it's going to be hardier than others. So you need to know the zone hardiness of your roses.
    Noisettes and Teas are going to be much more tender and need more protection.
    Keeping them near the house and out of winds will help immensely. I try to keep my most tender roses near a southern facing brick wall.
    Keeping them on concrete is not good for their little bottoms. Concrete will get colder and stay colder than earth. Try to put them on mulch or leaves.
    Roses in pots are considered a zone lower in hardiness. IE: a rose hardy to Zone 7 is considered a Zone 8 rose when it is in a pot. 10 degree difference for potted roses.
    Most of mine are in nursery pots so I can take a small 1G pot and put it into a 3G pot while mulching around and above the 1G. This will protect roots.
    I believe 3 days of lower than Zone temps will affect a rose. In other words, if the lowest temp of my Zone is 10 degrees and we have 3 nights expected below 10 (which happened in the blasted VORTEX last year) then I will put them in my unheated garage until super cold passes.
    I scavenged lots of Christmas firs on curbs last year. The branches are great to place around the pots if you corral them near the house. Eventually I had a sort of "cave" around and above the potted roses.
    Put the larger, hardier roses in front of the smaller to create "windbreak" of sorts.
    The only roses I've ever lost to cold are the tiny weakling refuse to grow coddlers that I just don't care about anymore anyway (Except for Eugene de Beauharnais).
    The best thing I've learned through experience is to keep them all in one area. Clustered together will help insulate them too.
    Good luck. As my pediatrician once said of children, "Relax, they're hard to kill."

  • susan4952
    9 years ago

    poorbutroserich,,,that is HYSTERICAL

  • Poorbutroserich Susan Nashville
    9 years ago

    Susan, I wasn't sure if anyone was going to get the jokeâ¦glad you appreciated it.
    Michael, thanks for clarifying. So would a concrete slab next to a brick wall be better or equal to dirt? Just put them on the ground and mulch around and over?
    I've dug enough holes this summer. My main concerns are my baby teas.
    Everything else seems to do just fine.
    Susan

  • Embothrium
    9 years ago

    You want the bottoms of the pots on soil, so that the warmth from the Earth is contacted. You don't, however want the pot bases sitting in puddles.

    I would protect the pots from temperatures in the 20s F. and colder. New roots of trees and shrubs in pots are about 20F less hardy, more or less than those in the ground. Old roots and tops are hardier, so potted plants left out in the cold may appear okay the following spring - but have actually lost all of their young roots. That is why top growth may be stunted the summer after cold exposure, part of the root system is gone.

  • michaelg
    9 years ago

    A slab next to a brick wall would be good if the wall faces south or east. Otherwise, the south or east foundation is a good, sheltered place.

  • Poorbutroserich Susan Nashville
    9 years ago

    Ok great Michael. The slab faces south and is really shelteredâ¦.I am so glad you debunked my concrete notion. It is the best place for my babies then.
    Susan

  • KnoxRose z7
    Original Author
    9 years ago

    Sorry for being MIA for a bit! I'd like to send a big Thank You to everyone who replied to this, I don't know what I'd do with out this information resource!

    Poorbutroserich, thank you for your advice especially, since we are fairly close geographically I really appreciate all your help (and your funnies too) I live in Knoxville, and fairly close to the city, so I feel like I'm a strong zone seven, even though some zone maps put me at a 6 (most say 7a)

    Michaelg, thank you as well, you cleared up many questions that I had about concrete & how it affects potted plants. Who knew there was so much to learn!

    This is what I have going right now, excuse the darkness of my photo, I took it last night after bringing everyone up to huddle on the porch before the cold hit. My porch faces the south east, so I hope this will be enough protection for them, at least during this sudden cold snap we are currently experiencing. Highs are in the 30s and lows in the 20s for the next couple of days, which is a huge drop from the 40s-50s we had been having. I feel pretty ok about most of them but I am a little worried about a couple of teas & noisettes (lady Hillingdon, duchesse debrant, crepuscule, etc) when it gets closer to zero I will probably take them to the basement. What do you all think?

  • michaelg
    9 years ago

    You could shove the tenderer plants and smaller pots against the wall where there will be some leakage of heat from the house, and during more extreme cold (10 or below), throw a blanket over them to retain heat from house and slab.

  • michaelg
    9 years ago

    I neglected to comment on the basement. Basements are generally too warm to maintain dormancy. You want an average temperature of 40 or below.

  • subk3
    9 years ago

    Diggle, the stuff I've read indicates that Lady H and the Duchess are a little more cold hardy than the average tea. My own experience west of you outside of Nashvegas is both that were bought as bands spring of '13 were zapped to the ground over the brutal winter. DdB did not come back and Lady Hillingdon made for a lovely 18" x 18" bush that bloomed like crazy all summer.

    I replaced Duchess de Brabant this spring with a 1 gallon instead of a band and all I got to say is both those roses are worth the extra fuss to keep them healthy through the winter!

  • Poorbutroserich Susan Nashville
    9 years ago

    I actually purchased a rolling unit and carted mine in and out of the garage if we were going below 25---that was for the wee ones. The larger ones I keep close to the house and enclose in a pine straw cocoon.
    You will be surprised at how tough theses roses are. It's just the littles that need thorough protection.
    Susan

  • buford
    9 years ago

    It's going down to the teens on Tuesday. We are getting rain today, so tomorrow I am going to load up as many pots as I can in the wagon and wheel them into the basement. The ones in the front can go in the garage.

  • seil zone 6b MI
    9 years ago

    My problem with concrete isn't it's temperature but it's porousness. It has a tendency to suck moisture out of the pots like a sponge. That's why I prefer to put something between the bottom of the pot and the cement. Desiccation will kill a rose quicker than cold temperatures. Drying winds are likely to be the main reason for cane die back in winter. Inside a garage you don't have that problem but you still have to keep moisture in the pot. A little water or a shovel of snow on the pot every month all winter will prevent them from drying out.

    Outside on soil you don't need to water because they will get water from rain and snow all winter...hopefully. But there have been years where there was very little snow fall and practically none under the eaves against the house where I put mine. I actually shoveled snow off the patio and onto the roses those winters.

    My best advice is to read through all of the good and varied advice here again carefully and decide what works best for you in your yard. You know better than anyone else where the warm spots and cold spots are and which of your roses are the most tender or hardy. Plan now how you want to arrange them and get everything ready so that when the time comes you can do it quickly and easily. However, don't jump the gun and do it too soon. You want them to go completely dormant first and then winterize they so that they will stay dormant through any minor temperature fluctuations until all chance of a hard freeze has passed. The purpose of winterizing isn't to prevent them from freezing but to prevent them from suffering the freeze and thaw cycle that is a real killer of roses.

    Much of what happens will be out of your hands anyway. If we have another very severe winter like the last one you may lose some no matter what you do. If it's more gentle you will probably be just fine.

    Susan, at 40 degrees don't your roses continue to try and grow? Mine do. I just had blooms open in 40 degree weather.

  • Poorbutroserich Susan Nashville
    9 years ago

    Seil, at 40 mine will try to bloom and grow. We've had low 30s and as of this morning I had blooms/buds on a significant number of roses. Some of my teas had 6 inches of deep red new growth and baby budsâ¦.
    But we got a hard freeze last night and it's predicted 19 tonight and for the next couple of nightsâ¦then highs in the 60s/lows in the 40s for the weekend. Dealing with the freeze/thaw is unavoidable for me. Wonder if I should strip foliage after they are truly dormant?
    Groanâ¦I swore I wasn't going to be a worrier this year.
    Susan

  • seil zone 6b MI
    9 years ago

    Sorry, I was asking Susan4952 how she keeps her roses all winter in a 40 degree garage. That seems much too warm to me. The roses wouldn't go and stay dormant and would use up all stored energy trying to grow with not enough light to produce more energy. Sounds like a recipe for trouble.

  • michaelg
    9 years ago

    Stripping foliage after the first rose-damaging freeze can slow the return of foliar fungus in the spring. Don't put the leaves back on the rose bed.

    Stripping foliage is completely optional--do it if you want to. I don't.

  • seil zone 6b MI
    9 years ago

    I don't strip them either. With the wind we get all winter by spring they're mostly gone and by the time I prune them that pretty much takes care of the rest.

  • Poorbutroserich Susan Nashville
    9 years ago

    Ok. Doggone it. I am just going to stop worrying this year. Everything is a reasonable size and well protected and damn the torpedoes. I have only a few that are truly irreplaceable.
    Susan

  • seil zone 6b MI
    9 years ago

    If you want just protect those irreplaceable ones and leave the rest. That should cut down on the work. The problem is we really have little control over it anyway. It's up to Mother Nature what kind of winter she wants to throw at us this year.

  • J B
    6 months ago

    So it’s been almost a decade since this post was active, but i have the same question as the original post, except i live in zone 4 (-20 to -30). Sorry in advance for a long post.
    I’ve been growing roses for 4 years (135+ in the ground and 10 in pots lol, since i forcibly retired). But every early Winter has been different. Like tonight we’re getting our first snow but the lows are going from low 40’s down over 4 days to 24,14,then 9 and 8, then next week it’s back up in the 60’s high/40’s low. My general rule of thumb is 3 nights at 25 or less (not lower than 15) then in the garage til Spring (May 15 is our last frost). Haha - but Mother Nature hasn’t cooperated the last few few years, as noted above (Sudden dive down to single digits after being 23 to 45).
    Last year i watered them with warm water before i went to bed down to 13, put them in the garage if lower than that. If the leaves still had green and weren’t crunchy, would leave the garage door up in the day (faces NW) if over 35.
    Overall worked, except 5 newly planted pots (Kashmir) in July were dead in the garage in May, before the last frost.
    My wife won’t let me put quilts around them outside, despite us never using them ( my granny in Gatlinburg made over 20 quilts just for me over the years, so we have plenty🤦🏽). And yes, for the TN’ers, Johnson City in the 1990’s was way colder and snowier than Knoxville/Maryville/Athens where i grew up in the 70’s. Montana is quite a bit worse haha as you can imagine, but worth it. Though last year in December, it went from 60 down to -30° for a week. Unusual, but that’s Montana. One Winter it never got below -5. And Billings (where I live) is way warmer than Bozeman (zone 3), so I should be grateful.
    Any suggestions when i should put the bigger pots (Pope John Paul, Munstead Wood, New Dawn, Plum Perfect) in permanently? Some pots are 16” w x 33’, most are 32” w x 25”. And the few Emily Carrs i started late Summer are only in 12” x 8”. The latter will go in after 25°. Help me pick options for the bigger ones:

    1. (most likely) i’m probably going to do the trolley shuffle back and forth at least from the South deck (somewhat exposed) to the pavement up against the NW driveway (although the big pots weigh 50lbs or more DRY lol, so my back would prefer not to lift and put them on the trolley unless permanently going in the garage for the Winter).
    2. I could leave them on our South facing deck which is full sun and elevated, and against glass walls, but it would likely still be single digits up there.
    3. put everything in the garage if below 15°, then back out if higher.
    4. warm water them at bedtime and put in the NW driveway.
    5. warm water but put them on shady NW ground.
    6. put them on a full shade North concrete floor patio/brickwall alcove with warm water for single digits, and leave them until consistently below 25, with the shade hopefully getting them dormant quicker, although the garage may still warm up to 50 in a few weeks.

    Sorry for all the options, but you guys sound as obsessed as I am about my babies haha. (Wife thinks i’m crazy, but the roses at least keep me out of the house and away from her for part of the day lol, again, now that I’m retired). And the neighbors go ape over all the flowers, so it’s fun.
    Thanks for reading this long post, and for any suggestions on what you’d do.☺️🌹