Flowers have no growth mechanic, so that is very difficult.
Bees will spawn flowers at random, but the chance to get roses is fairly low. You could also build an elaborate redstone contraption aking to classic vanilla automated farms that cycles through applying bonemeal to grass blocks and flooding the area to pop off and carry away the resulting flowers. However, you're still more likely to get a ton of grass and yellow flowers than any significant amount of roses.
There's one thing though that you could try - vanilla flowers, including roses, are a valid plant for the rarely-used IC2 crop farm system. Cropsticks have their own growth mechanic that overrides existing plant rules; for example, if you plant a pumpkin seed in it, it will grow the pumpkin plant inside the cropstick instead of spawning pumpkins on adjacent blocks, and they can be harvested with a rightclick without breaking the plant itself. Maybe something similar works with roses? I have never tried it, but give it a whirl.