Common Name: Tar Vine

General Information

Boerhavia diffusa is a herbaceous perennial plant with vigorous, many-branched stems growing from a taproot; up to 2 metres long the stems can be erect or procumbent[, , ]. The stems branch mainly from the base, they are prostrate when young, becoming ascending to erect when flowering[].
A very popular medicinal plant, especially in India, where it is widely used in Ayurveda. Medicines containing this plant are sold worldwide. The plant is gathered from the wild and is also sometimes used as food.
The plant is a weed of cultivated land and wasteland, often in lawns in drier areas. The small fruits are very sticky and grow close to the ground. They can therefore attach to human clothing or to animals and birds, enabling wide dispersal of the plant. Although common, it is not a weed of importance. After mechanical cultivation the plant resprouts from its roots but relatively few cultivations are needed to exhaust it[, ].

Known Hazards

The very viscid perianth tube containing the fruit readily adheres to other objects and detaches itself from the plant. Small insects are caught by the secretion, and young chickens and turkeys sometimes die in consequence of their eyes becoming sealed up by the sticky fruits[].

Botanical References

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Range

The original native range is unclear, the plant is widespread in the tropical regions of Africa, Asia, America, Australia and the Pacific Islands.

Habitat

Open places near the sea, dry and warm river valleys; at elevations from 100 - 1,900 metres in southern China[]. Along roadsides, near habitations, in and along cultivated fields and in open cleared patches in forests[].

Properties

Weed Potential	Yes
Edibility Rating
Medicinal Rating
Habit	Perennial
Height	1.00 m
Cultivation Status	Wild

Cultivation Details

Boerhavia diffusa is widespread through much of the tropics and the subtropics and has also become naturalized in parts of the temperate zone
Prefers a sunny position and a sandy, well-drained soil[, ]. The plant grows wild in a range of soil types[]. Prefers a pH in the range 6.6 - 7.8[].
Plants can commence flowering when only 4 weeks old from seed. The plant can flower and produce fruit all year round if sufficient water is available[].

Edible Uses

Root - eaten by the Aborigines of central Australia[]. The root is long, thick and fleshy[, ].

Leaves - cooked as a pot herb or added to soups[, ]. Occasionally used as a vegetable[].

Seeds - cooked[]. Added to cereals[].

Medicinal

Spreading hogweed is used in traditional medicine in several parts of its range, but is especially popular in India where it is a part of the Ayurvedic tradition. The whole herb, including the root, is used and it is said to be bitter, diaphoretic, diuretic, emetic, expectorant, laxative and stomachic[, ].
Research has shown the presence of an alkaloid, beta sitosterol and various other compounds in the roots[]
An alcohol extract of the whole plant has shown significant antiinflammatory activity, a cardiotonic effect, an increase in blood pressure, a relaxant effect and promising diuretic activity[].

The plant is emetic and purgative[]. It is used in the treatment of various conditions including gastric disturbances, asthma, jaundice, anascara, anaemia and internal inflammation[, , ]. It has also been used as an antidote to snake venom[].

A decoction of the leaves is used to treat jaundice[, ]. The leaves are used in a cataplasm for treating indurated liver[].

The root can be used as an ipecacuanha (Carapichea ipecacuanha) substitute[]. Antispasmodic, very astringent, diuretic, emetic, emmenagogue, purgative and sudorific herb, it can be used in a decoction to treat dysentery and a range of other conditions[].
The boiled roots are applied to ulcers, abscesses and to assist in the extraction of Guinea worm[].

Agroforestry Uses:

Boerhavia diffusa is recorded as a host for the virus causing aubergine mosaic disease (EMV); as a host of zucchini yellow mosaic polyvirus (ZYMV); and as an alternative host for the cotton aphid (Aphis gossypii)[].

Other Uses

None known

Propagation

Seed - we have no information on this species but suggest sowing the seed in a greenhouse in the spring. When they are large enough to handle, prick the seedlings out into individual pots and grow them on in the greenhouse for at least their first winter. Plant them out into their permanent positions in late spring or early summer, after the last expected frosts.
Cuttings