Ontario Weeds: Catnip

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Excerpt from Publication 505, Ontario Weeds, Order this publication

Table of Contents

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

Name: Catnip, Nepeta cataria L.,

Other Names: herebe à chat, chataire, népète chataire

Family: Mint Family (Labiatae)

General Description: Perennial, reproducing by seed and by very short underground rhizomes.

Photos and Pictures





Catnip.  Leaves.

Stems & Roots: Stems erect, 40-100cm (16-40in.) high, square, densely white-hairy; leaves opposite (2 per node) on different sides of the square stem at successive nodes, heart-shaped, longer than wide, densely covered with short, soft, white hair, especially on the underside; margins coarsely toothed, each tooth with rounded sides and a blunt point; petioles about half as long as leaf blades;

Flowers & Fruit: Flowers dull white, in dense, whorled clusters in axils of leaves near ends of stems and branches; calyx short, tubular, of 5 united sepals forming a short tube with 15 parallel veins and ending in 5 narrow, sharply pointed soft teeth; corolla dull white with purplish dots, formed from 5 united petals, 10-12mm (2/5-½in.) or sometimes longer and about 6mm (¼in.) wide, irregular, trumpet-shaped but 2-lipped at the end, the upper lip with 2 lobes, the lower lip with 3 lobes; each flower producing a cluster of 4 nutlets ("seeds") which are smooth, reddish-brown with 2 white spots at the lower end. All parts of the plant have a characteristic odour resembling mint, and the whole plant is frequently gray-green due to a dense covering of fine white hair. Flowers from July to September.

Habitat: Catnip was widely cultivated throughout Ontario and has escaped from cultivation in all parts of the province so it now occurs in open forests, meadows, pastures, waste places, roadsides, around buildings and in gardens.

Similar Species: It is distinguished by its erect habit of growth, square stems, the opposite, stalked, coarsely toothed, heart-shaped leaves, its dense, whorled clusters of dull white flowers, its prominent trumpet-shaped 5-lobed corolla about 12mm (½in.) or longer, and its distinctive odour that is so attractive to cats.

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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