In the first place, they don't eat your roses; all they want are the circles they cut from the foliage to line their nests with. These circles removed may cause the foliage to be unsightly, but the nesting season will soon be over and new leaves will come in. Leaf cutter bees are excellent pollinators, so their cutting capers can certainly be tolerated for a short period of time. If you want more info on them, why not type their name into Google, and see what you can find on them?

We have them in Israel we well and last summer they seemed to prefer my Systane-sprayed Iceberg over my non-sprayed Garden Director. Iceberg was lacy for a while. I happened upon one of the bees while she was at it. Fascinating. I didn't even mind Iceberg getting shredded in front of my very eyes. Iceberg got over it pretty quick. It seems to get over just about anything.

Leaf cutters ( totally harmless) are attracted to certain roses here and not at all interested in some others. I don't think it has anything to do with your additional pollinating plants that attracts them as they seem to have minds of there own on what they will munch on and not munch on. The plant victims here (roses and others) seem to remain the same each year, if your thinking about moving rose(s) or plant(s) to prevent them from getting to others would be just a wasted effort. There homes are rather small in size they borrow in pen tip sized holes. (Example: a pruned rose cane.) You could use Elmers glue to close the hole(s) it might slow them down a bit but there homes will be many as well. Other than that the only thing I would suggest is to let them do there thing and enjoy it as a work in progress. What I mean by this is ... You know when you deadhead roses and then some new roses re bloom ? Think of the leaf cutter bees as natures way of "deadheading" foliage and for the better part more effective.

I know a little from having had them visit us in Texas, but I haven't seen them very much here. They actually tunnel in pithy wood, so sometimes you can see sawdust on the ground near wherever they are building their nests (often in older rose canes). Those little leaf circles they cut are used inside the tunneled-out area to build the cells of their nest. They are very solitary so you don't see a lot of them at one time. And, as you have noticed, they like certain plants more than others, so they keep coming back to their favorites and ignoring other plants. They never did enough damage to a plant that it suffered, at least not that I could tell. New foliage always came out to replace the damaged leaves, but if they completely stripped a branch or twig, I always pruned it off (after they were done) to stimulate new growth. As far as I know, they have very few natural predators, and the ones I know of (parisitic wasps and flies) are predators you don't want to encourage, because they also go after butterfly cats. If it really, really bothers you and you fear for the life of your plants (smaller plants would find it harder to rebound from the destruction of their foliage), you can keep the bees off by covering them with floating row covers/sheer curtains/something similar. In general, though, they cut enough leaves to build the cells in their nests, and then they're gone. And, their population is not at all consistent....very heavy some years and almost nonexistent other years, so you may not see them again any time soon. Dawn