They aren't as close as they look. I went for 12" as they're grouped together by variety and I feel sure I'll need to cull some of them. They're named varieties and were given to me as leftovers from a sale day. I know little about the varieties and need to do some research asap, of course. I do want them close enough to choke out weeds down the road, but for now, I thought 12" would give them plenty of room to establish themselves before losing their brothers! In general, though, I sure agree with you!
