I found a mixed packet of seed that includes white, blue, yellow, and lilac - not sure how many of each but the recommendation was to just direct sow in the winter. I was thinking if I did a winter sowing I could prick them out once they came up and then set out individual plants rather than having clumps here and there. I wouldn't know the color until they bloomed, unless there is some distinction in the leaves (I doubt that), but having a mixture would actually be pretty.