Practical ecological knowledge for the temperate reader.

Hemp-Nettle - Galeopsis tetrahit

Family: Mint [E-flora]
Other Names: (brittlestem hempnettle)[E-flora]

Poisonous, Drying Oil, Cordage

"Galeopsis tetrahit is a ANNUAL growing to 1 m (3ft 3in). It is not frost tender. It is in flower from Jul to September, and the seeds ripen from Aug to October. The flowers are hermaphrodite (have both male and female organs) and are pollinated by Self.The plant is self-fertile.
Suitable for: light (sandy), medium (loamy) and heavy (clay) soils. Suitable pH: acid, neutral and basic (alkaline) soils. It can grow in semi-shade (light woodland) or no shade. It prefers moist soil." [PFAF]

"General: Annual herb from a taproot; stems erect, 20-80 cm tall, coarse, branched when well developed, 4-angled, bristly-hairy, including red-tipped glandular-hairs, below nodes."[IFBC-E-flora]
"Leaves: Opposite, egg-shaped to lanceolate, 3-10 cm long, 1-5 cm wide, coarsely blunt-toothed, tips pointed, bases rounded or wedge-shaped, stiff-hairy; stalked." [IFBC-E-flora]
"Flowers: Inflorescence of several dense axillary flower clusters, subtended by upper leaves; corollas tubular, purple or pink or white with dark markings, 15-23 mm long, the upper lip arched and entire, the lower 3-lobed, spreading, the middle lobe flat, entire, often nearly as wide as long, bearing 2 nipple-like protuberences on the upper side near base, its network of dark markings restricted to the base, not reaching the margins; calyces about 1 cm long at flowering, somewhat larger in fruit, the erect spine-tipped teeth about equaling tube, the tube strongly 5-ribbed, hairy within; stamens 4, anthers hairy."[IFBC-E-flora]
"Fruits: Nutlets, 4 clustered together, egg-shaped, 3-4 mm long, smooth." [IFBC-E-flora]
"Notes: Galeopsis tetrahit originated from G. pubescens Bess. and G. speciosa Mill. by hybridization and polyploidy. The species may have arisen more than once, and may owe some of its variability to various origins." [IFBC-E-flora]

Habitat / Range
Moist to mesic waste places and forest margins in the lowland, steppe and montane zones; frequent throughout BC south of 56degreeN; introduced from Eurasia. [IFBC-E-flora]
"Arable land, sometimes in woods, fens and wet heaths[17]. Europe, including Britain, from Iceland and Russia to Spain and Macedonia." [PFAF]

Origin Status: Exotic [E-flora]


The plant is poisonous, causing paralysis[74]. [PFAF]

Other Uses

Medicinal Use



"Grows in most soils, disliking heavy shade. This plant is sometimes grown in the wild garden[200]. An aggregate species[17]. It is a natural hybrid, G. speciosa x G. pubescens[200]." [PFAF]

"Seed - sow spring in situ[200]. Germination usually takes place within a month." [PFAF]

Galeopsis sp.

Local Species;

Possibly encountered exotic species


Split-lip Hemp-nettle - Galeopsis bifida

Syn: Galeopsis tetrahit var. bifida

Habitat / Range
Moist to mesic waste places and forest margins in the lowland, steppe and montane zones; frequent throughout BC south of 56degreeN; introduced from Eurasia. [IFBC-E-flora]

Hazards The plant is poisonous, causing paralysis[74].[PFAF]
Other Use "A drying oil is obtained from the seed. It is used as a polish for leather[74]." [PFAF]

HEMP NETTLE (Galeopsis sp.) [HMH Duke]
"Activities (Hemp Nettle) — Antiulcer (f; MAD); Astringent (1; BIS; HHB; PHR); Diuretic (f;HHB; PHR); Expectorant (1; HHB; PHR); Hematogenic (f; EFS). " [HMH Duke]
"Indications (Hemp Nettle) — Anemia (f; MAD); Asthma (f; EFS); Boil (f; MAD); Bronchosis (2; KOM; PH2); Cancer (f; MAD); Catarrh (2; KOM; PIP); Congestion (f; MAD); Cough (2; PHR; PH2); Dermatosis (f; MAD); Eczema (f; MAD); Furuncle (f; MAD); Gastrosis (f; MAD); Itch (f; MAD); Pulmonosis (1; PH2); Respirosis (2; KOM; PIP); Splenosis (f; HHB); Stomachache (f; MAD); Tuberculosis (1; HHB); Ulcer (f; MAD); Water Retention (f; HHB; PHR)." [HMH Duke]
"Dosages (Hemp Nettle) — 6 g/day herb (KOM; PIP); 2 g herb/cup water 1–3 ×/day (HHB; PHR; PH2); 3 tsp (5.7 g)/cup herb tea (MAD). " [HMH Duke]

Galeopsis sp. "Whole plant: boiled as famine food, served with potatoes, oat flour, milk or butter, probably until the turn of the 19th and 20th century, Mp [45]." [Lucaj&Szymanski]

Galeopsis ladanum; A good source of edible oil [Svanberg EE]

Hempnettle - Galeopsis segetum

"...hemp-nettle Galeopsis segetum, which has yellow flowers. It is used in lung complaints and as a diuretic and is available under its synonym, Galeopsis ochroleuca for the indications of asthma and enuresis." [TWHT]


Page last modified on Tuesday, May 2, 2023 9:31 AM