The Scilla madeirensis I grew from BX 284 seed (planted fall 2011) have only this year really purpled up. Perhaps the mail order bulbs are still young and are large from a richer soil? They like as much sun as you can give them and are sensitive to cold. When I repot them, I expose most of the bulb and they pull down to the height they want which has at least the "neck and shoulders" above ground.