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Common Name: Slender Mint
Mentha diemenica is a perennial plant that can grow up to 0.10 metres tall.
It is harvested from the wild for local use as a food, medicine and source of materials.
Although no records of toxicity have been seen for this species, large quantities of some members of this genus, especially when taken in the form of the extracted essential oil, can cause abortions so some caution is advised.
Australia - New South Wales, Tasmania, Victoria.
Moist, usually sunny situations up to the montane zone[
]. Open forests and grasslands, usually on sandy soils[
We do not have much information on this species and do not know if it will be hardy in Britain, though judging by its native range it should succeed outdoors at least in the milder parts of the country. Plants tolerate temperatures down to at least -7°c in Australian gardens[
], though this cannot be translated directly to British gardens due to our cooler summers and longer colder and wetter winters. The plants also tolerate occasional trampling[
]. The following notes are based on the general needs of the genus.
Succeeds in most soils and situations so long as the soil is not too dry[
]. Prefers a slightly acid soil[
]. Grows well in heavy clay soils. A sunny position is best for production of essential oils, but succeeds in partial shade.
Most mints have fairly aggressive spreading roots and, unless you have the space to let them roam, they need to be restrained by some means such as planting them in containers that are buried in the soil[
Hybridizes freely with other members of this genus.
The whole plant has a mint-like aroma.
The flowers are very attractive to bees and butterflies[
]. A good companion plant for growing near cabbages and tomatoes, helping to keep them free of insect pests.
Members of this genus are rarely if ever troubled by browsing deer[
Leaves - raw or cooked. Used as a flavouring in summer drinks[
A herb tea is made from the leaves[
The leaves and flowering stems are carminative, diaphoretic, diuretic, emmenagogue and stomachic[
]. A tea made from the leaves of most mint species has traditionally been used in the treatment of fevers, headaches, digestive disorders and various minor ailments[
]. The leaves are harvested as the plant comes into flower and can be dried for later use[
The essential oil in the leaves is antiseptic, though it is toxic in large doses[
An essential oil is obtained from the whole plant. The plant is used as a strewing herb for repelling insects[
]. Rats and mice intensely dislike the smell of mint. The plant was therefore used in homes as a strewing herb and has also been spread in granaries to keep the rodents off the grain[
Seed - sow spring in a cold frame. Germination is usually fairly quick. Prick out the seedlings into individual pots when they are large enough to handle and plant them out in the summer. Mentha species are very prone to hybridisation and so the seed cannot be relied on to breed true. Even without hybridisation, seedlings will not be uniform and so the content of medicinal oils etc will vary. When growing plants with a particular aroma it is best to propagate them by division[
Division can be easily carried out at almost any time of the year, though it is probably best done in the spring or autumn to allow the plant to establish more quickly. Virtually any part of the root is capable of growing into a new plant. Larger divisions can be planted out direct into their permanent positions. However, for maximum increase it is possible to divide the roots up into sections no more than 3cm long and pot these up in light shade in a cold frame. They will quickly become established and can be planted out in the summer.