Blue Ageratum By Stephantom (Own work) [CC BY 3.0], via Wikimedia Commons
Container Role: Filler
Amount of Shade: Part Shade
Blue Ageratum* is one of the truest blue flowers to be found, and they are very easy to grow from seed.
It is in the daisy family so needs deadheading, otherwise, it is care free.
Ageratum looks lovely in containers as a filler, paired with dusty miller, blue salvia and blue or white allysum.