O.k. a tip cutting with NO flowers is what you need (if you take a cutting it's last act is to put all it,s energy into growing roots. if it has a flower it will put the last of it's energy into growing seed!).
take a cutting 2-4 inches long from healthy shoots.
remove all but top 1-2 sets of leaves. (the plant has no roots to supply water to the leaves. less leaves mean less water loss & more chance of survival)
gently re-cut with a very sharp blade at a 45 degree angle, 1 centimeter below a node (that is where a branch or leaf attaches to the stem). - a 45 degree cut gives the best surface area for the cut to take up water.
soak in WARM water for a few minutes, this will relive shock & help to stop any air bubble that may form in your cut (embolism) which stops water travelling up to the plant.
adding a small amount of seaweed fertiliser to the soaking water will greatly relive stress, which greatly increases your chance of success.
there is a product called "superthrive" 1 drop in a bucket of warm water will nearly guarantee your success. it is the greatest there is, almost like magic-truly amazing stuff. hard to find- not cheap, but worth every cent & can last for ages if used wisely!
then dip the cut end into a rooting hormone (they all work well, some are powder some a gel. i find the gel easier to apply & it stays on better! pure honey (NOT from the supermarket- it must be fresh,untreated , un-pasturised honey, that is "bush honey") will also work as a rooting agent!! it works fantastic & no man made chemicals or hormones etc to deal with.
dip & cover to about 1cm above you node.
then into an inert medium (that is something like potting mix, with NO nutrients) i like rockwool cubes - no nutrient & they also hold a lot of air, which is very important to stop stem rot & root disease.
DO NOT ADD ANY FERTILISER!! - the plant has no roots it will burn! even when it starts to grow roots they will be young & delicate & will only handle 1/4 strength fertiliser, until you have potted it up for a couple of weeks.
bottom heat will speed the rooting process_ e.g. a heatmat under your cuttings, @ about 22 degrees (approx).
the transpiration (water loss through evaporation of the leaf surface) will dry out & kill you cuttings. a plastic "hood" of some kind with small holes for some airflow will slow down this evaporative water loss.
you can buy one or cut the top off a plastic bottle to slip over your plants. i use stiff wire to create a frame them cover the frame with a layer of cling wrap.
keep out of direct light, put in shade with some indirect light.
check the media (what you are growing in) doesn't dry out completely. but let it dry out a little before watering- DO NOT KEEP IT SATURATED!!. it will die it needs air & water, to the roots. if its always wet it will start drowning & you will get fungal problems which really,really suck & will spread easily to other cuttings!
spring is the time to do this as the daylight hours increase, & the ground heats up.
you can do all this indoors under a small flurolight, with a timer set for 18hours on & 6 hours off (same as a long summer day).
you can succeed without a rooting gel - it just really increases the chance of success. indoors you can get perfect results.
getting roses to strike is increadibly simple! follow these siple steps & yoe can't go wrong. (i dunno why robert.c would have any problems, but don't do it in winter when the plants not growing! obviously it will die)
i know this will help
p.s. is your avatar Lactrodectus Hasselti?