Is this a good garden plant? Could it work as a companion plant for roses? I'm a sucker for blue flowers,and am looking for good groundcover-types. But I know that common bindweed is also a type of convovulus,and I HATE that weed, am struggling valiantly to get rid of it from my garden (it loves the compacted soil). I hesitate to try C. mauritanicus, because I'm worried that it will wind up being kind of "genetically bullied out of my garden" by the bindweed; i.e.,Pollinators will cross-breed the bindweed with the C. mauritanicus, and I'll just wind up with more bindweed. Also, does it stay open in the afternoon, or is it like morning glory that only opens in the morning? Thanks in advance!