To create an old-fashioned border, mix blue Ageraturm with pink begonias and white Alyssum. For a low-maintenance combo, try Dusty Miller mixed with blue Ageraturm and lemon yellow Marigolds. Add a few white petunias for a crisp look. [From Annuals For Michigan by Szerlag & Beck]
Tall flowering Ageratum, such a ‘Blue Horizon’ makes a nice addition to container gardens as well as a filler for perennial borders.