Can you pot and winter over (outside) knockout roses?

Question

I bought a pitiful Knockout Rose "tree" (hoping it is a knockout). I was hoping to pot it, prune it and hope it makes it till next spring. I live in southern MD, is it possible to let them sit in a pot all winter?

Answer 1

The pot you select for over wintering your knockout rose can be just important to its survival as is your preparation for over wintering. Roses need room in a pot. Selecting too small a pot for a rose will lead to death. Your pot should be at least 16-18" in diameter. In terms of over wintering your rose, the bigger the pot, the better the chance of survival through the winter. Root systems can not tolerate temperatures much below freezing without suffering root damage or death. Clay pots are good at insulating the roots from the cold, but a clay pot will crack in freezing weather. Metal pots will conduct the cold to the root system. Thin plastic pots offer little to no protect to the roots from the cold. Wood & concrete pots both offer good insulation, but concrete can crack from the freezing temps. Remember all pots need good drainage to prevent water pooling in the bottom.

Do not keep your pots elevated above the ground on a deck or other structure. Pots elevated tend to allow roots to be exposed to ambient outside temperatures and plants almost never survive below freezing temps, even in zone 9. For the same reason, pots should not be stored on top of a concrete patio.

Living in zone 9 or lower in Maryland means that you probably experience a lot of freeze-thaw cycles. Your roses should be watered up until the ground freezes. Once the ground in the pot freezes, the drain holes become ineffective. Freeze-thaw cycles, rains and melting snows can create very wet soils above the frozen ground in the bottom of a pot. These cold, wet soil conditions can be very problematic for roots. Therefore, it is best to store your pots on their side in winter to allow moisture to spill out. Finally, your rose will benefit from some added insulation around the pot. Either bury your pot in soil (on its side) or mulch your pot (on its side). I hope you find this information useful and good luck on over wintering your knockout rose.

P.S. With a knockout rose there should be no reason to prune until spring and then prune for shape and or any winter kill.

Answer 2

Given your in Southern Maryland then I'm assuming you are zone 9 and since you have such a warm climate, you can have potted roses without worry. The only danger to a potted rose is root damage due to freezes and becoming root bound. I would suggest that you put it in the ground if you can because roses just tend to do better there. Knockout roses are very hardy and with a little TLC it should recover nicely. As long as there is green then there is hope. Also, if it is truly a knockout rose then you don't have to prune it unless it has dead or dying canes. Knockouts dead head themselves and the most they need is trim to keep them in check. If you do pot it then it will need a very large container because roses hate to be root bound.
Good Luck with your rose.

Answer 3

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RE:
Can you pot and winter over (outside) knockout roses?
I bought a pitiful Knockout Rose "tree" (hoping it is a knockout). I was hoping to pot it, prune it and hope it makes it till next spring. I live in southern MD, is it possible to let them sit in a pot all winter?

Answer 4

Much of Maryland is zone 7-8( according to my search but double check) and Knockouts are good for zones 4-9. When you leave a plant in a container, you generally subtract 20 degrees because it is more susceptible to the cold versus being in the ground but you should be fine expecially if you can put it in a protected area and give it several hours of sun and water when needed.