Herbicides or weed killers, such as Round Up, contain glyphosate. Also known as glyphosate-mono (isopropylammonium)
This is a systemic chemical and will stay in the ground for extended periods of time when used to kill weeds either in a garden bed, lawn or sprayed to create edging.
It can contaminate roses via direct contact or as airborne spray, ie. the chemical may drift through the air for a distance before coming in contact with roses.
If effected, bare root roses may not break dormancy, while established roses will produce multiple shoots coming from the leaf buds. This will be spiky short and deformed.
If the plant is a large specimen and is affected only on some branches, you may be able to cut the affected branches out. Glyphosate will go to the growing end of a cane.
If badly affected this process can take a year or more to sort out. It may not be worth the struggle and a new plant should be purchased.
If used on the soil in a garden bed then you may need to replace the top layer of soil.
Important: signs and symptoms will vary significantly between varieties, even within similar categories. The information provided here is a basic summery of the most common affects and will not always be applicable to all rose varieties.