Bluebells - what gorgeous color they bring to one's garden. Bluebells are a perennial; they come up each spring, and are a delight. I have several planted in a shady area underneath an oak tree. The best time to plant these bulbs are in the late summer or early fall. Mulch the area over the winter. Bluebells spread rapidly; they can be divided every couple of years in the late summer or early fall.