And remember that it's a common mistake to plant perennials too close together. I always mistakenly overbuy (or over commit) perennials. They need space to spread.
Annuals, on the other hand...ram them in close. At least in Minnesota! The season is so short, we pack them tight so as to get the most pop for the most time in the summer.
2007 Trek 5000
2009 Jamis Coda
1972 Schwinn Suburban
"I rejoice every time I see a woman ride by on a bike. It gives her a feeling of self-reliance and independence the moment she takes her seat; and away she goes, the picture of untrammelled womanhood."
Susan B. Anthony, 1896