Henrik,

I don't go to much by the pith color of two year or older growth, just the color of last year's growth.

As a cane ages to two years or more, its pith color will not retain its creamy color, especially in climates like yours and mine. It will darken, especially in its very center.

People who grow roses in climates where temperatures do not drop below -7C, generally do not have much pith color darkening on 2 year or older canes.

I advise you to prune to good creamy pith on last year's growth, and on older growth go more by the appearance/color of the cane's surface along its length.

Does its surface color match the color of a typically same aged healthy cane for that variety of rose? If so, that cane is in good stead.

If, as spring progresses, an additional pruning back can be done as needed, if the new growth on suspect canes is showing serious sickliness.

Moses

Pith color is a hybrid tea rule. If you aren't growing hybrid teas, forget about it. With once bloomers, the most important thing is how well the cane leafs out. If it leafs out well, it is fine. If it doesn't, it has problems.

Thanks for the replies but I think I'm even more confused now. All
”professional” advice seems to suggest that anything but white
pith = damage, regardless of rose class. I did try a previous year
not to prune a cane from the year before with brown pith that looked ok on the
outside to see what would happen (and this was indeed a hybrid tea).
It started to leaf out from several bud eyes but then just collapsed
midway, before setting any buds.

I'm not sure I understand why it would be any different with a Gallica for example? Here's part
of a last year basal cane from a Gallica (Gesualdo da Venosa) that
looks perfectly green on the outside but mushy brown inside. Would
this really be able to produce a good quantity of quality flowers?

Henrik,

No way on God's green earth! All last year's canes must have creamy pith or they will fail.

Moses

I'll try and get some pictures. That cane looks perfectly normal to me. However, I usually wait and prune once bloomers after they are well leafed out, and only prune out obviously dead canes. So the "proof in the pudding" would have been if those bud eyes grew into healthy leaves or if they sat and did nothing.

I seriously suggest you ignore the once bloomers for a year or two, just to see what they do. Since they are almost always sold own-root over here, we have to manage them differently. We tend to go very light on the pruning

Is there no one else who grows roses in a cold climate who can shed some light on Henrik's pith question? Come on, help him out, please.

Moses

I do and the canes that you show are not good. They will not be able to transport nutrients which is vital to a healthy blooming rose. Most of canes that your showing will eventually yellow and die off anyway. Your instincts are correct to prune to healthy tissue. I do not see how on earth a rose can bloom its best while growing on winter killed canes. I hope not to offend anyone.

Even though a cane looks brown in the centre, it may have enough moisture to make some new growth. But in a short time the new growth will collapse and die. Brown centers in a cane is a definite sign that the cane is struggling to live and in time will die.

Mad is right, though, that the cane will declare itself. If you wait, the new growth will either look normal or need to be pruned off later if it fails, and looks yellow, and damaged, which will also work fine.

Thanks for the additional replies. There won't be much left of the roses but I think I will go ahead and prune to healthy looking pith, even on old canes (maybe just leave one or two canes). I don't want them to waste energy on shoots that will soon die anyway.

I had already pruned the Gallica in the last couple of photos down to white pith and this is what remains. I guess I will be lucky to get any flowers from it this year (planted last spring and is yet to flower at all)...

I've often tried to leave canes that looked like that. I always hope they'll be OK. But from experience I can tell you that even if that cane leafs out it will eventually die back.