I cleared away a bunch of mostly oak leaves from around a few rose bushes (thinking about the danger of canker when it is cold and wet), and discovered, hidden by the leaves, several basal breaks. I've never seen them this early before. The bushes haven't even been pruned yet. Do you think they will be alright and grow normally if temps drop in the 30's at night (heating back up to 50's usually) as long as it doesn't go to 32F?

There was a precious basal break on my Ebb Tide; to be on the safe side I carefully mounded the base of the rose. I worry about canker and rot, too, so I try to use some non-organic stuff like wine corks (I save them for this purpose ) or small pieces of styrofoam. I make a little "rampart" in a circle around -but not touching- the rose's base out of soil. I fill this in with the non-organic material,trying to have only the non-organic stuff actually touching the plant,then I top it off with more soil. In other words, the soil is ideally like a sort of shell, holding the corks or styrofoam chips in place,but actually touching the plant as little as possible.

They'll be fine. However, you might want to put the leaves back. They seem to have done a pretty good job if the rose sent up new shoots. No where is damper than Michigan in the winter and I RARELY get canker and leaves are my main winter protector. I bury my pots in leaves from late November through March. Sacramento can't be that wet, and certainly not for that long, can it? Just leave them alone until it's time for spring pruning/

Seil, you are probably right BUT I do want to point out that Rosemary is in California,where it is also warmer than in Michigan. Now, as you know, I am in Tuscany-also much warmer than Michigan-and on occaision I have lost new basal breaks during the winter, and one winter lost many roses to canker and rot. Now, in part, I think the fault for that was in part the mounding material that I used-earth or bagged manure. What happened was that there was a very cold snap (for our area),and then it became much warmer, soggy and rainy. At the time I was having health problems and couldn't go out to check on things, either,until it was too late. I think if it's cold and stays cold, the risk is lower.
I do remember losing an un-mounded basal break on an established Souv. de Mme Leonie Viennot, and this was in a pretty normal winter. Now,SdeMLV is a gigantea, I think, and therefore perhaps more susceptible. So, I repeat-you are probably right, that they will be fine with just the leaves; after all, they have been so up until now. I just think though that the temperature swings in my climate can sometimes be harder on plants (and people) than steady cold might be.

Thank you Seil, and Bart.

Now I am still undecided. When I found them two days ago, they were all white shoots (7 basal breaks on two bushes, in total!), one 4" long growing horizontally under several inches of leaves. After being uncovered for a day, they were turning red, and the daylight (even if it's foggy and not sunny) will cause them to grow upward rather than just horizonal under the leaf cover, so that's a good thing, I think. In the past, canes have been plagued with canker. Last year I was very diligent in keeping leaves cleared away, and I almost no canker, so that makes me think the leaves in the past could have been a cause. But then I think about all the roses everywhere that are actually planted below the bud union where it freezes and mounded with leaves that are wet, etc., and they are pruned to the ground every spring after leaves are removed, and they come back year after year just fine, so that would be a reason not to be concerned about the leaves mounding over the base....just thinking aloud here!

We are not considered frost-free (at risk for 32 and below into the 20's) until March 27, but last year it stayed above 32, and so far it has this year also, but usually if we have some, it is in Dec. and Jan.

Guess I will keep a close eye on them, and on the weather, but maybe I will let the rest of the leaves stay for the time being if it fosters basal breaks!

The leaves are not fostering the basal breaks. The rose is just putting on new growth because the weather is warm enough to allow for it. It is not cold enough to put them into dormancy. The roses will grow, no matter what you do, if the conditions are right for them to do so. I have this conversation all the time with cold climate growers who think that stopping fertilizing, stopping dead heading etc. will make their roses go dormant for the winter. It doesn't. They will only stop growing when it is too cold for them to do so any longer.

I often have that white growth on my potted roses in the spring when I uncover them. The roses store energy for new spring growth in their canes in the fall (which is why you should never prune in the fall). When it starts to warm up the rose wants to grow so it uses that energy to put out new sprouts. Because it is buried in leaves it does not get any sunlight so it can not produce chlorophyll to make them green. Once uncovered they do begin to green up. When the rose is uncovered and growing if some of those shoots seem pale and weak I simply remove them and new ones will sprout. The point is the rose needs that early growth it produced from the stored energy to put on new leaves so it can begin the process of photosynthesis to produce food for more new growth. And it only has a certain amount of the energy stored. Once used up, if it has not produced more leaves, it can not feed itself and will die. In cold climates that is what happens because we have many false starts to spring. It can be 50 for several days and then drop back into the teens for a couple of weeks and it yo-yos back and forth like that for a couple of months. That is what kills a lot of roses in the north. Mulching and protecting is not to keep the roses warm but to keep them asleep for as long as possible by maintaining an even temperature through those ups and downs until real spring comes and stays so the rose can safely begin to grow and doesn't waste that precious stored energy in new growth that is doomed to die off in the next sudden freeze.

I know you said that you can get freezes but how cold are we talking about? Roses can take temperatures down to about 27 degrees without sustaining any damage. Particularly if it is for only a few hours during the night and then the temps go right back up to above freezing during the day. Most damage is done when temps fall into the teens and stay there for long periods of time. Like days! Which I often get in February. I have had stretches of days where temps NEVER got into double digits and weeks we never got ABOVE freezing. And somehow the roses survive. They are really tougher than you think and harder to kill than you would ever believe.

My advice still stands, just leave them alone and wait for spring. They will be fine.

Thank you, Seil, for sharing more in depth from your experience and knowledge of rose growing in variable cold temperatures and the effect with dormancy and temps where it doesn't really go dormant. In the last 30 years, I can remember only twice that it went into the 20's, and then it was the upper 20's. I've read it can go lower, but it hasn't for many years. I found your post very interesting!

I would like to share my observations about protecting the crown ( and thus basal breaks) with dry oak leaves. These take at least two full seasons to break down here. So if I use fesh dry leaves piled up to the graft union, there's very little chance they will rot the first winter, however wet or damp the winter may be. The reason for their long stay is possibly their very high content in tannins that deterr rotting away. So mulching with dry oak leaves ( plentiful in California) possibly is the easiest and most practical alternative. I do have poplar leaves in fall too. These yes soak up quickly and might cause rot. So I'm being specific of what to use.
My understanding of what we see and call as canker is actually scarr tissue ( like when one is severely burnt) caused by the burning of ice of the epidermis of the cane. The disease may exist or not but the scarr tissue will remain visible. The disease is caused by several different types of bacteria. Not always when I see scarr tissue there's the canker disease developing. That explains why sometimes the plant overcomes the tissue damage, the canker 'heals' and the cane becomes functional regardless the outside looks of it. On the contrary if the bacteria get hold of the weakened area the disease progress blocking the flow of nutrients and the far away section of the cane dies. I don't think that canker causes rot. Yes, dead parts of canes might eventually rot if not removed soon enough.

Arturo

So now the basal breaks are 4'-6", and it's predicted to get down to 28 F. tonight, followed by rain for the rest of the week. Do these basal breaks need to be protected at high 20's or they will be ruined/damaged? I just re-read the above responses and it sounds like they might be ok. if they are not protected.

An hour or two at 28 shouldn't do damage but if it is going to remain that cold for a long period of time then mulch them up with leaves or what ever you have on hand. Do not try and cover them. The weight of the heavy rain will crush them. And NEVER use any kind of plastic in the garden. It will transfer the cold even faster.