more on pruning climbing roses

Fire

With climbers - where there is a fork how do we know which one to prune off - in order to grow one strong cane? Does it matter? Do the hormones just swap over if we don't know which is the main cane and which the off-shoot? Does it take considerable time for the plant to do the homonal switch? Is choosing just a matter of going for one with a better size and least damage? Thanks

punkdoc

I would aim to try and train both those main shoots horizontally, then the growth that rises vertically from those shoots will bear flowers.
You want to aim for a network of horizontal shoots at various heights.

Fire

I understood that there can be only one main cane (per picture) and the other will be (hormonally) a shoot.

Mr. Vine Eye

Both of those are main canes.

I think some sources talk about main canes being canes that are coming from below ground level (or from the base of the plant) but they can also start higher up.

It depends on how you prune/treat them. It's like how with an espalier tree, you tie the main branches that you have selected horizontally to encourage new shoots to grow all along the length of the branch. Then you prune back the lateral side shoots which are trying to become leafy stems to encourage them to become fruiting spurs. But if you didn't prune back those laterals then they would be trying to grow and become new leading stems. Some people use this to create more elaborate espalier designs by extending the structural branches in interesting shapes.

On a climbing rose you do a similar thing, you train the structural 'main canes' horizontally (or near to horizontal) to encourage lateral side shoots all along the length of the cane. Then after flowering and in winter you cut the laterals back shorter to encourage more flowering shoots to grow from that point in the future and stop them getting too long.

If you just left a lateral shoot to grow long then it would try to go vertical, stiffen up and become structural with flowers just at the very tip. So a lateral side shoot can become a 'main cane'.

Short answer:

I think main cane just means a cane that is being used to support the structure of the rose plant - they can be a side shoot from another main cane.

That's my understanding anyway.

Nollie

As I understood it the main cane is the one growing directly from the ground, with both of those offshoots being lateral canes that produce the flowers, but not 100% sure. It is odd to just have the one main cane and have it pruned back as in your photo if that is what it is. I suppose it depends what you are trying to achieve - a kind of standard effect, or do you need to squeeze it into a restricted space? Seems a shame to lop off one of only two canes. No idea about the hormone thing...

Dovefromabove

In your pic the initial main cane has been cut back in order to encourage side growth ... which has happened and now you have two side shoots which have grown into strong canes and both of which will have the apical hormone at the tip which has encouraged upward growth. 

The usual way of growing climbing roses is to train  the two side canes  towards the horizontal to slow down the flow of growth hormone to the tips, thereby encouraging the development of  side shoots which will bear the blooms.  

As others have said, not sure why you'd want to remove either of those canes ?

Fire

"It is odd to just have the one main cane and have it pruned back as in your photo if that is what it is. "

I think the main cane got damaged - in one picture, which is why it's cut like that. It was not intentional. I think that's why there's a fork. I thought that there could hormonally there was one main cane - with flowers coming on the offshoots. I'm probably wrong, but was trying to learn from watching vids like this from Zimmerman Roses.

Mr. Vine Eye

edhelka

It depends on the rose, I would guess it will support both canes and both will grow. In any case, I wouldn't cut either. Even if one of them doesn't grow more, you will still get laterals out of it if you train it horizontally. And laterals mean not only more flowers but also more leaves = more energy for the rose. I wouldn't cut healthy growth if it can be trained, the rose put energy into growing that cane and deserves to get some energy back, by producing laterals and leaves on that cane.

Fire

Thanks for all your thoughts.

Fire

@Mr. Vine Eye   I have messaged you. Thanks