Spanish Bells

Spanish Bells (Hyacinthoides hispanica), also known as Bluebells, are bulbs that will happily grow just about anywhere.

Excellent under a deciduous tree. They have small bells of pink, white or blue on upright stems with strong green foliage.
English Bluebells (Hyacinthoides non-scripta) are somewhat similar in appearance but have curved stems resulting in the individual flowers hanging away from the stem.