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: Rosin Weed

General Information

Grindelia squarrosa is a Biennial/Perennial up to 1.00 metres tall.
It is harvested from the wild for local use as a food, medicine and source of materials.

Known Hazards

The plant contains the carcinogen safrole[].

Botanical References

, ,

Range

N. America - Quebec to Virgina, west to British Columbia, California and Texas.

Habitat

Prairies, plains and dry banks[, ]. Disturbed sites, plains, hills, roadsides, along streams, sands, clays, and subalkaline soils at elevations of 200 - 2900 metres[].

Properties

Edibility Rating
Medicinal Rating
Habit	Biennial/Perennial
Height	1.00 m
Pollinators	Insects
Cultivation Status	Wild

Cultivation Details

Succeeds in any well-drained soil in full sun[]. Does well on dry sandy banks and in poor soils[]. Prefers a peaty loam soil[].
This is one of the first species to invade disturbed or denuded ground and often becomes a serious weed of grazing land[].
A very polymorphic plant[].

Edible Uses

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[].

Medicinal

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[].

Other Uses

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

Propagation

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.