Not in water!
There are several ways o root rose cuttings. The best is to take a good 6" cutting and insert it into either a pot of good quality potting mix! Then cover the cutting with a large size mason jar. Water cutting and place it somewhere that receives some morning sun.
Make sure there is at least one node (where the leaf is attached to the stem) is a few inches below the soil surface. Remove the leaf before inserting it into the soil, but leave the top ones!.
The second method is to prepare a spot in the garden.
Add lots of organic matter such as compost, well aged manure and peat moss, work this into the soil! Pat the area down to help settle the soil then water it.
Insert the cuttings ( I usually do several just to make sure you get at least one cutting roots...you can always give the others away) the same as in a pot with the node below the soil surface. Then cover the cuttings with mason jars (a gallon size works best!).
Keep the soil moist during the rooting period.
Rooting usually occures in a few weeks, to a few months, so you will need to be patient!
You will know something is happening if the cuttings send up new growth.
To be sure, you can give the cutting a gentle tug, if it resists, that means the cutting is rooted.
Leave then where they are over the next winter still covered with the glass jars. Next spring you can move them where you want them to grow!