▁flower . ▁ ▁The ▁fra gr ant ▁flowers , ▁( similar ▁to ▁ros es , ▁and ▁vio lets , ) ▁blo om ▁between ▁March ▁and ▁May . ▁The ▁flowers ▁are ▁very ▁variable ▁in ▁colour , ▁they ▁are ▁Pol ym orphism ▁( bi ology )| pol ym orph ic , ▁they ▁can ▁come ▁in ▁sh ades ▁from ▁white , ▁yellow , ▁blue , ▁l il ac , ▁to ▁vio let . ▁They ▁also ▁can ▁be ▁bi - col oured . ▁The ▁flower ▁also ▁can ▁very ▁rarely ▁be ▁pale ▁yellow ▁with ▁vio let ▁ve ins , ▁similar ▁( but ▁less ▁than ) ▁to ▁I ris ▁var ieg ata . ▁The ▁most ▁common ▁colour ▁is ▁deep ▁blue ▁vio let , ▁or ▁pur ple ▁blue . ▁The ▁flowers ▁are ▁larger ▁than ▁I ris ▁pseud op um ila ▁and ▁I ris ▁revol uta . ▁ ▁Like ▁other ▁ir ises , ▁it ▁has ▁ 2 ▁pairs ▁of ▁pet als , ▁ 3 ▁large ▁sep als ▁( outer ▁pet als ), ▁known ▁as ▁the ▁' falls ' ▁and ▁ 3 ▁inner , ▁smaller ▁pet als ▁( or ▁te p als ), ▁known ▁as ▁the ▁' stand ards '. ▁The ▁dro op ing , ▁sub - elli ps oid al ▁falls ▁are ▁ ▁long ▁and ▁ 2 – 3 . 5   cm ▁wide . ▁In ▁the ▁centre , ▁they ▁have ▁a ▁be ard , ▁which ▁is ▁either ▁blue ▁or ▁white , ▁but ▁t ipped ▁with ▁yellow . ▁The ▁shorter , ▁ob liqu ely ▁u pr ight ▁standards , ▁are ▁