I've inadvertently sprayed round-up on roses, and even deliberately, and it hasn't killed them. I don't know that there's any point at this stage in cutting off the canes. But, I will add, that I tried very hard to kill a badly diseased Mrs Dudley Cross, cutting her to the ground, and painting with roundup and banging in a copper nail. She came back with a vengeance, so I removed the nail!

Trish

I would spray all the roses with lots of water immediately, and also water them well (unless they are already drowning in rain). Then I would just leave them alone. Let them be, and later (or next Spring) you can cut off the damaged parts - I think you are correct that they need all of the leaves they have right now, Round up is awful stuff, and it travels through the air when sprayed - folks who use it around plants they do not want to kill sometimes paint it on specific things they ARE trying to kill with a brush instead of spraying it. Not something which should be used casually.

I've found Dorothy Perkins thrives on it as well, Trish. Jacqueline, I had to RU kikuyu grass that invaded my front rose bed 3 days ago. Trimmed the roses down a bit then wrapped them in large plastic bags until I finished. It should work as I did this in another bed last year. The areas to cover are too big for the paint brush unfortunately, although it is good for spot weeding. I'd prefer not to use RU but I could excavate to Europe and not get all the kikuyu runners. : )

Keeping it watered is always good but if it's been a month or more it's probably a little late to hope to get it off. You can cut off anything that is deformed or unsightly. Be fore warned, you may continue to get odd growth for a year or more before all of the affects wear off. It takes a long time for the plant to clean all that toxic stuff out of it's systems.

With regards to purposefully killing a rose, I find it difficult to believe there are roses you cannot kill with glyphosate if you try. The cut and paint the stub method works for large trees I cannot believe it cannot work on roses if you do it properly. You need to paint undiluted concentrated solution on the cut (the ready to spray solutions won't do) and you really need to do it when the plant is not dormant. Best time for woody decidous plants is in autumn while they are preparing for dormancy. It is then that there's lots of downward 'juice activity'. Adding a bit of ammonium sulphate helps. You only have a very limited time window between cut and application so you need to paint the stuff on immediately after the cut. For roses I would cut the canes down low but leave enough green cane on (as if I were hard pruning) and paint on each one of the canes. Not letting dirt get on the cut before application is important. If the stem is thick and woody one should take care to paint on the outer areas of the cut, there's no point in painting on the xylem.

Nik, I did all that last spring and autumn, but didn't know about adding ammonium sulphate as well. How much would I need to add? DP is over 32 yo and own root and the base is nearly 30 cms across. It did put out spray affected growth over winter and I thought it was gone but it has put out new healthy looking growth this spring. At present it is cut back to stubs, so is it worth trying again now or leaving until autumn?

Just a teaspoon to 250ml will be enough. You can also add a couple of drops of dishwashing liquid to act as a surfactant. You need to have a freshly cut area of live cambium to apply. The larger the better. Alternatively you can try scratching off the woody bark and apply to the phloem or drill holes from the top just underneath the bark and apply the stuff in there. If you have enough live cambium and the plant is growing, I would try it now (your spring) also.

Nik, just to let you know, I cut and painted undiluted (extra strong) glysophate straight away. Mrs DC just laughed.

Well, if glyphosate cannot do it (which I still doubt), triclopyr ester (e.g. Garlon 4) plus basal oil or kerosene, applied to both the cut and the stub bark will... But we are entering the realm of pretty dangerous things (both for the garden and for you).

Btw, we are not talking about pure glyphosate here. Pure 100% glyphosate will not work, it needs to be diluted down with water. We are talking about the concentrated glyphosate solutions commercially available which are commonly 18% or 36% strength. I use a 36% strength solution of generic glyphosate which I dilute slightly. Try 36% undiluted if higher dilutions had no effect.

Once damage appears plant is already long affected. Apart from usual care all you can do is wait for recovery. Abnormal growth may continue to appear for some time.

Thankfully, I see some more normal looking leaves popping out now during our recent 2 weeks of 70 degree weather. Hopefully the danger is past.

Well

It looks great!

A beautiful recovery! Carol

Please, please people DO NOT USE ROUNDUP OR GLYSOPHATES. They are very poisonous to humans and dangerous to the environment. You can read more about it on my own thread on the Rose forum called "Why we should avoid herbicides (Roundup and glysophates in general" (I'm not linking to that because it caused a hissy fit in one person),but here's a helpful link put up by Hans: http://www.collective-evolution.com/2015/05/30/why-the-netherlands-just-banned-monsantos-glyphosate-based-herbicides/