The Temperate Database is in the process of being updated, with new records being added and old ones being checked and brought up to date where necessary. This record has not yet been checked and updated.

Common Name: Tarweed

General Information

Cuphea viscosissima is an erect, much-branched, annual plant usually growing up to 50 cm tall. The plant is sticky to the touch due to the presence of glandular hairs on the purple stems[, , ].
This is one of several species in this genus that have been identified as potential commercial seedcrops, grown for their oil.

Known Hazards

None known

Botanical References

,

Range

Eastern and central N. America - Nebraska to New Hampshire, south to Louisiana and Florida.

Habitat

Open woods, glades, prairies, fields, rocky barrens, roadsides and waste places[]. Dry, open soils[].

Properties

Edibility Rating
Medicinal Rating
Other Uses Rating
Habit	Annual
Height	0.50 m
Pollinators	Butterflies, Humming birds
Self-fertile	Yes
Cultivation Status	Wild

Cultivation Details

Cuphea viscosissima is the hardiest member of a mainly tropical genus. It can be grown outdoors in much of the temperate zone, restricted mainly by its need for a hot summer in order to produce a good crop of seed.
Succeeds in any reasonably fertile soil in full sun or part shade[, ]. Tolerant of dry conditions[].
Cuphea has only been investigated as a potential commercial crop for a few years, and still has the characteristics of a
wild plant. Those characteristics that differ from cultivated plants are its propensity to seed shatter, its indeterminate flowering nature, and its overall stickiness. If these wild traits can be overcome, Cuphea's chemistry, coupled with the annual and therefore renewable nature of the plant, certainly can make it a new crop.
This species is self-fertile[].
Germination in central European climate is slow (14 - 20 days) even in late May after the last frosts, but this is made up for by quick growth and early seed ripening.
Germination is slowed by the thick seed hull. The first seed is produced six weeks after sowing in the greenhouse.
In regions where the plant is winter hardy, it will often self-sow in gardens[].
The stems, leaves and flowers are covered with sticky hairs giving rise to one of the common name s for this plant of 'clammy cuphea'.

Edible Uses

An oil obtained from the seeds has the potential to be used in foods[].

Medicinal

The plant is used in homaeopathy, in particular to treat vomiting of undigested food[].

Agroforestry Uses:

In the US it has been suggested to plant Cuphea in rotation with corn and soybeans every three years. If grown this way Cuphea can help disrupt the life cycle of corn rootworms - pests that account for more pesticide use on US row crops than any other insect. (Corn rootworms can cost up to $1billion per annum in control and yield losses)

Other Uses

The seeds, although small, are a potential commercial crop for their oil. The oil is a good source of medium length fatty acids - these oils are usually obtained from tropical sources such as palm and coconut oils. This species is particularly rich in capric acid (75.5%)[].
Industrial oils made from these acids are valuable commodities as they have the potential to replace others made from imported palm kernel and coconut oil. Lauric acid is used in foods, mostly as vegetable shortenings, as a defoaming agent and a booster for soaps and detergents.
Medium chain length fatty acids (e.g. Lauric and myristic) are used in detergents and health and beauty products. Statistics show that 71,000 tonnes of lauric acid oils were processed during 1991 in the EC; they originated from Copra (i.e. Coconut) and Palm kernel
Cuphea has been used as an alternative to coconut oil in soaps, detergents and other products

Propagation

Seed - can be sown in situ after the last expected frosts[]. In order to obtain larger plants, extend the growing season and hopefully achieve larger yields of seeds, the seeds can be sown in a greenhouse in early spring at around 21°c. Germination usually takes a few weeks because of the hard seed coat. Prick the seedlings out into individual pots as soon as they are large enough to handle and plant out after the last expected frosts[].