Ontario Weeds: Cleavers

Table of Contents

1. Name
2. Other Names
3. Family
4. General Description
   • Photos and Pictures
5. Stems and Roots
6. Flowers and Fruit
7. Habitat
8. Similar Species
9. Related Links

Name: Cleavers, Galium aparine L.,

Other Names: gaillet grateron, Spring cleavers, Goose-grass, gratteron

Family: Madder Family (Rubiaceae)

General Description: Annual, reproducing only by seed.

Photos and Pictures

Cleavers, showing backward- or downward-pointing hairs on stems and whorled leaves.

Cleavers. A. Lower and upper parts of a mature plant. B. Portion of stem enlarged to show the backward-pointing bristles.

Stems & Roots: Stems weak or reclining, 10-121cm (4-48in.) long, square in cross-section with strongly ribbed corners, with very short, downward- or backward-pointing, firm, hair-like, curved bristles; leaves usually 3 to 8 in a whorl, linear, tapering at the base, mostly 1-8cm (2/5-3-2/5in.) long, with bristles at the pointed tip, somewhat hairy on both surfaces and with many very short, backward-pointing bristles on the margins. These tiny hook-like bristles on stems and leaves cause them to cling together in masses and to cling to clothing, skin or fur, hence the common name, "cleavers."

Flowers & Fruit: Inflorescence mostly 1- to 5-flowered; flowers very small and soon replaced by the small spherical fruits; fruits bristly, 1.5-4mm (1/16-1/6in.) in diameter. Flowers from May to August.

Habitat: Cleavers is found in southern Ontario in woods, meadows, compost heaps, gardens and fields, and along roadsides and riverbanks.

Similar Species: It is distinguished by its square, weak, clinging stems, its bristle-tipped leaves that also cling with backward-pointing bristles on the margins, and all leaves arranged in whorls of 3 to 8 at each node of the stem.

Related Links

... on general Weed topics
... on weed identification, order OMAFRA Publication 505: Ontario Weeds
... on weed control, order OMAFRA Publication 75: Guide To Weed Control

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