Leptospermum

Leptospermum is a genus of about 80-86 species of plants in the myrtle family Myrtaceae. They are distributed throughout Australia, with the greatest diversity in the south of the continent; two species also extend to Malaysia and one (Manuka L. scoparium) to New Zealand.

They are shrubs or occasionally small trees, reaching 1-8 m tall, rarely up to 20 m, with dense branching. The leaves are evergreen, alternate, simple, sharp-tipped, and small, in most species not over 1 cm long. The flowers are up to 3 cm diameter, with five white, pink or red petals.

Uses
The common name of 'tea tree' used for some species of Leptospermum derives from the practice of early Australian settlers of soaking the leaves of several species in boiling water to make a herbal tea rich in ascorbic acid (Vitamin C). It is said that Captain Cook brewed tea of Leptospermum leaves to prevent scurvy amongst his crews.

The nectar from the flowers is harvested by bees; this is used to make Leptospermum honey. Manuka honey has strong antibacterial and antifungal properties.

In Australia, Leptospermum species are sometimes used as food plants by the larvae of hepialid moths of the genus Aenetus, including A. lewinii and A. ligniveren. These burrow horizontally into the trunk then vertically down.

Most Leptospermum species make desirable garden plants. The hardiest species (L. lanigerum, L. liversidgei, L. polygalifolium, L. rupestre, L. scoparium) are hardy to about &minus;8°C to &minus;10°C; others are sensitive to frost. They tolerate most soils and exposures with good drainage and full sun. Established plants are drought tolerant. They are often found as hedge plants on the west coast of the United States, and some species are popular for cultivation as bonsai. Many cultivars exist.