Answer: periwinkle

AnswerCrossword Clue
PERIWINKLESnail.
PERIWINKLEBlue color
PERIWINKLEFlower
PERIWINKLESaltwater snail
periwinkleAn Old World plant with flat, five-petaled flowers and glossy leaves. Some kinds are grown as ornamentals, and some contain alkaloids used in medicine
periwinklea creeping plant with blue flowers also PENNYWINKLE