Geranium x cantabrigiense can make a nice, weed suppressing ground cover if you give it enough water. It isn’t very ‘thirsty’, but it has its needs. Larger more aggressive weeds can invade it, but I use it in my garden. Geranium macrorrhizum, one of its parents, does the same, only it is a larger plant and is more effective on larger weeds. It is a balancing act. The rhizomes of each are relatively easy to remove if need be unlike a lot of other rhizomatous spreaders.