Native: North and Central America, Europe, Asia and North Africa.
Growing Region: Zones 6 to 9.
Flowers: Spring through to autumn.
Flower Details: Blue, purple; can be pink or white. Clustered. Tiny. Hooded.
Fruit: Small red berries. Summer through autumn.
Foliage: Evergreen. Mat forming. Mint-like. Petiolate. Narrow ovate. Stiff stem.
Sow Outside: Cover seed. Start of spring - before the last frost.
Sow Inside: Germination time: one to two months. Temperature: 55 to 65°F (13—18°C). About 2 months in advance. Transplant outdoors in spring. Spacing 12 to 18 inches (30—45 cm).
Requirements and care: Full sunlight or partial shade in hotter areas.
Soil pH 6 to 7.5. Moist soil. Tolerates dry soil in cooler regions. Regular watering during prolonged dry spells in warmer areas. Cut back to the ground once flowering has completed. Propagate: by dividing in the spring autumn; self-seeds freely and may become invasive.
Closely Related Species: Mints and Sages.
Miscellaneous: Many species are lawn-weeds and can be difficult to control as they are resistant to many lawn weed killers; the plant is useful the rock garden, in borders, and is often grown for its herbal properties. Has long been used in Europe as a ‘treat all’ plant, hence its name; where it was used in the treatment of wounds, burns, heart conditions and even as an anti-cancer agents. In traditional Chinese medication it is used in an herbal drink to treat liver complaints. Self heal was traditionally used by indigenous North Americans to treat boils, cuts and inflammations.
How to Grow Self Heal and Other Prunella Species
Sow the seeds of Self Heal and other Prunella members outside at the start of spring before the last frost.
The seeds should be lightly coved once sown. Ideally they should grow in a soil of pH 6 to 7.5.
Prunella plants can grow in both sunny and partially shaded locations of the garden.
If starting off indoors, then do so about ten weeks in advance. They should be transplanted outdoors in the spring.
It should take from one to two months for the seeds to germinate at a temperature of 12 to 18 degrees centigrade (54 to 64°F).
Once the seedlings are ready, transplant outdoors with a spacing of about 30 to 45 cm (12 to 18 inches).
Caring for Prunella
It is easy to grow and look after Prunella species in the garden. They require regular deadheading of old flowers to maintain attractiveness, and to encourage further blooming.
Once the flowering season is over, cut the plant back to ground level.
It is a good idea to plant Prunella in a confined area of the garden, such as a rock garden, and to control them rigorously, as they can easily take over the garden (especially the lawn).