Self-heal is a low-growing perennial of lawns, meadows, verges and other grassy places. Its compact purple flower heads are easy to overlook among short turf, but once noticed they are very distinctive.
It belongs to Lamiaceae, the mint family. Like many members of this family it has opposite leaves, a square-ish stem and two-lipped flowers, although Self-heal is much less strongly aromatic than many familiar mints.
Identification
- Usually around 5–30 cm tall, often creeping or spreading through short grass.
- Dense, oblong to short cylindrical flower heads at the ends of the stems.
- Flowers violet, bluish-purple or occasionally pinkish or white.
- Individual flowers are distinctly two-lipped, with a hooded upper lip and a broader lower lip.
- Leaves grow in opposite pairs and are oval to lance-shaped, usually with only shallow teeth or almost entire margins.
- Stems are typically four-angled, a common mint-family feature.
- After flowering, the purplish-brown bracts remain and make the old flower head conspicuous.
The combination of opposite leaves, compact purple flower heads and persistent overlapping bracts makes Self-heal fairly easy to recognise in flower.
Flower structure
What looks like one short flower spike is made up of many individual flowers arranged in crowded whorls.
Each flower has a fused corolla forming two lips. The upper lip is hooded, while the lower lip provides a landing area for visiting insects. The flowers sit among overlapping bracts, which can become strongly purple-tinged as the head matures.
As in many members of Lamiaceae, the ovary is deeply four-lobed and later forms four small nutlets.
Leaves
The leaves are arranged oppositely, with one leaf directly across the stem from the other.
They are usually oval or narrowly oval, on short stalks, with a rounded to pointed tip. The margins may be almost smooth or have a few shallow teeth.
On flowering stems the uppermost pair of leaves normally sits just below the flower head.
Habitat
Self-heal is widespread and grows particularly well where grass is fairly short or open, including:
- meadows and other grassland
- roadside verges
- lawns
- field margins
- woodland rides and clearings
- parks and gardens
It tolerates mowing well and can persist in lawns where herbicides are not used.
Flowering period
Self-heal flowers mainly from June to October, although individual plants may begin earlier in favourable conditions.
Similar species
Bugle (Ajuga reptans) also has purple-blue flowers and opposite leaves, but it usually has a more obvious upright spike with flowers in separated whorls and commonly spreads by creeping runners.
Ground-ivy (Glechoma hederacea) has rounded, kidney-shaped leaves with scalloped edges and flowers in the leaf axils rather than a compact terminal head.
Woundworts (Stachys species) are generally taller and have more clearly toothed leaves, with their flower whorls spaced along a longer stem.
Folklore & history
Self-heal has one of the most descriptive names in the British flora. For centuries it was valued as a wound herb, and names such as heal-all and carpenter’s herb reflect this traditional use.
The plant was especially associated with cuts and bleeding. The 16th-century herbalist John Gerard praised it as a wound herb, while Nicholas Culpeper later explained its name through the idea that an injured person could gather the plant and “heal yourself”.
Its long medicinal reputation is also reflected in the scientific genus name Prunella, which has been linked historically with remedies for throat complaints.
These traditions are an important part of the plant’s cultural history, although they should not be taken as modern medical advice.
Wildlife
The violet flowers provide nectar for bees and other insects through much of the summer. Because Self-heal grows happily in lawns and other short grass, allowing small patches to flower can add a useful nectar source to otherwise closely managed ground.
Its low growth habit also helps it fit naturally into species-rich lawns and short wildflower turf.