- Name also: Goosegrass, Hairif, Clivers, Stickyjack, Stickywilly, Stickyweed, Stickyleaf, Catchweed, Coachweed
- Family: Bedstraw Family – Rubiaceae
- Growing form: Annual herb.
- Height: 30–120 cm (12–50 in.). Stem limp, 4-edged, hook-haired. Hooked hairs with oval bases.
- Flower: Corolla wheel-shaped, white, 1.5–2 mm (0.06–0.08 in.) broad, fused, 4-lobed. Calyx lacking. Stamens 4. Pistil of 2 fused carpels, styles 2. Inflorescence a lax, 2–5-flowered axillary cyme.
- Leaves: Regular (actinomorphic), usually 4–8 whorled eaves. Blade narrowly elliptic–oblanceolate, with short bristle, hook-haired on top, edges and underside along central vein, with entire margins.
- Fruit: 2-parted, hook-haired schizocarp. Carpels almost spherical, 3–5 mm (0.12–0.2 in.) broad. Hooked hairs with rounded bases.
- Habitat: Seashore seaweed piles, waterside hedgerows and broad-leaved forests. Also fields, gardens, wasteland and loading areas.
- Flowerin time: July–September.
Cleavers’ stem, leaves and fruit are covered in small, oval-based hooked hairs. These hundreds of tiny hooks enable cleavers to attach itself to neighbouring herbs and hay to support its limp stem. Its fruits and even the whole stem attaches easily to animal fur and people’s clothes – so it has no problems finding new habitats. Cleavers has spread far and wide from its original home, where it is regarded as quite a nuisance herb. It is not harmful in Finland, however, as it is quite rare. Its original habitats are seashores and kelp piles.
Cleavers’ hooked hairs were for a long time used to clean milk: they attracted the cow hair and other bits of rubbish that had fallen into the pail during the milking. According to one explanation this has been the source of its scientific name Galium, which comes from the Greek word gala, which means milk. On the other hand many species have been successfully used to process milk.
Cleavers looks very much like its more fragile relative false cleavers (G. spurium), although its flowers are only about a millimetre across and lime green, and its leaf blades are slightly narrower and long-bristled. A closer inspection also reveals differences in the species’ hooked hairs, which do not have oval bases on false cleavers.