Ontario Weeds: Motherwort
Table of Contents
- Other Names
- General Description
- Stems and Roots
- Flowers and Fruit
- Similar Species
- Related Links
Name: Motherwort, Leonurus cardiaca
Other Names: agripaume cardiaque, agripaume,
Family: Mint Family (Labiatae)
General Description: Perennial, reproducing
only by seed.
Photos and Pictures
Motherwort. A. Top of plant before flowers open.
B. Mature calyx with its 5 slender, spiny-tipped lobes.
Stems & Roots: Stems erect, 40-180cm
(16-70in.) high, square, somewhat hairy along the angles, branched,
frequently several stems from 1 coarsely fibrous root crown; leaves
opposite (2 per node), lower ones long-stalked, rounded in outline,
palmately cleft into usually 5 or more main lobes which are coarsely
or irregularly toothed, upper leaves on shorter stalks, smaller,
and only 3- or 5-cleft.
Flowers & Fruit: Flowers in the
axils of small upper leaves; calyx tubular with 5 slender, sharp
lobes, 3 pointing upwards and 2 downwards, becoming hard, sharp,
and spiny at maturity; the calyx breaking off and clinging as a
bur to clothing or fur; corolla pink to pale purple or whitish,
upper lip conspicuously white-hairy, not lobed, lower lip 3-lobed;
each flower producing 4 nutlets ("seeds") which are triangular,
dark brown and hairy at the apex. Flowers from June to August
Habitat: Motherwort occurs throughout
southern Ontario in yards, waste places, fence lines, and roadsides.
Similar Species: It is distinguished in
non-flowering stages by its palmately lobed leaves (almost like
maple leaves) in geometrically precise arrangement in 4 vertical
planes around the square stem. Flowering and fruiting plants are
distinguished by their palmately lobed leaves, clusters of pinkish
flowers in leaf axils, and the calyx of each flower with 5 very
sharp lobes, 3 pointing upwards and 2 downwards, these becoming
spiny bur-like clusters on mature and dry stems.
... on general Weed
... on weed identification, order OMAFRA
Publication 505: Ontario Weeds
... on weed control, order OMAFRA
Publication 75: Guide To Weed Control
to the Ontario Weeds Gallery |