Herb: Rosin Weed

Latin name: Grindelia squarrosa

Family: Compositae

Medicinal use of Rosin Weed:

Rosin weed was used by the native North American Indians to treat bronchial problems and also skin afflictions such as reactions to poison ivy. It is still used in modern herbalism where it is valued especially as a treatment for bronchial asthma and for states where phlegm in the airways impedes respiration. In addition, it is believed to desensitize the nerve endings in the bronchial tree and slow the heart rate, thus leading to easier breathing. The plant merits investigation as a treatment for asthma. The herb is contraindicated for patients with kidney or heart complaints. The dried leaves and flowering tops are antiasthmatic, anti-inflammatory, antispasmodic, expectorant and sedative. The principal use of this herb is in the treatment of bronchial catarrh, especially when there is an asthmatic tendency, it is also used to treat whooping cough and cystitis. The active principle is excreted from the kidneys, and this sometimes produces signs of renal irritation. Externally, the plant is used as a poultice to treat burns, poison ivy rash, dermatitis, eczema and skin eruptions. The plant is harvested when in full bloom and can be used fresh as a poultice or dried for infusions etc. A fluid extract is prepared by placing the freshly gathered leaves and flowers in a small quantity of simmering water for about 15 minutes. A homeopathic remedy is prepared from the leaves and flowering stems.

Description of the plant:


100 cm
(3 1/4 foot)

July to

Habitat of the herb:

Prairies, plains and dry banks.

Edible parts of Rosin Weed:

The fresh or dried leaves can be used to make an aromatic, slightly bitter but pleasing tea. A sticky resinous sap that covers the leaves can be used as a chewing gum substitute.

Other uses of the herb:

Yellow and green dyes are obtained from the flowering heads and pods. Aromatic.

Propagation of Rosin Weed:

Seed - sow autumn or spring in a cool greenhouse and only just cover the seed. Prick out the plants into individual pots when they are large enough to handle and plant them out into their permanent positions in early summer. Division as new growth commences in the spring. Very easy, larger clumps can be replanted direct into their permanent positions, though it is best to pot up smaller clumps and grow them on in a cold frame until they are rooting well. Plant them out in the spring. Cuttings.

Cultivation of the herb:

Prairies, plains and dry banks.

Known hazards of Grindelia squarrosa:

The plant contains the carcinogen safrole.

Plant information taken from the Plants For A Future.