Prunella is a member of the mint family, so that tells us immediately that it is a vigorous, spreading plant.
There are seven species of perennials in the Prunella family, and they all produce spikes of tubular flowers with two lips, similar to the snapdragon flower. The blooms come in violet, pink, and white, and the leaves usually form thick mats of foliage. If they have sufficient moisture in full sun or partial shade, the plants will spread, as the leaf nodes root easily. In addition, these plants self-sow, especially in areas where the summers are not hot.
Plants should be cut back after bloom to avoid the seeds self-sowing. They divide easily in spring or fall, but the main challenge with these plants is to prevent them from taking over in zones 5-8.
Prunella grandiflora is a vigorous, six-inch tall perennial that spreads to form three-feet wide mats. The leaves are round and toothed, and the upright spikes are purple, and the flowers appear in summer.
A variety called ‘Loveliness' comes in pink, white, and pale lavender.
A common name "self-heal" reminds us that in times past this plant was used medicinally.