Ontario Weeds: Large crabgrass

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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. Related Links

Name: Large crab grass, Digitaria sanguinalis (L.) Scop.,

Other Names: digitaire sanguine, Finger grass, Hairy crab grass, digitaire pourpre, panic sanguin

Family: Grass Family (Gramineae)

General Description: Annual, reproducing only by seed.

Photos and Pictures

Large crab grass, viewed from the side.
Large crab grass, viewed from the side.

Large crabgrass

Large crabgrass

Large crabgrass. A. Plant. B. Leaf-base. C. Side view. D. Back view of a portion of spike with several spikelets.

Large crabgrass. A. Plant. B. Leaf-base. C. Side view. D. Back view of a portion of spike with several spikelets.

Stem and leaf-base characteristics of a typical grass.

Stem and leaf-base characteristics of a typical grass.

Stems & Roots: Stems 5-120cm (2in.-4ft) long, erect, spreading, or lying on the ground and rooting at nodes in contact with the soil; leaves numerous near the base of the plant and scattered along the stems, 4-20cm (1 1/2-8in.) long, 5-10mm (1/5-2/5in.) wide and gradually tapered towards the pointed tip; leaf blades and leaf sheaths sparsely to densely soft-hairy; the hair standing more or less straight out; leaf sheaths split, the margins hairless and overlapping; ligule membranous, 0.5-2mm (1/50-1/12in.) long; no auricles.

Flowers & Fruit: Inflorescence finger-like, with several thin, slender, spikes in a whorl at the top of the stem, or more usually with 2 or 3 sets of branches from the upper 2-4cm (4/5-1½in.) of stem; each spike ("finger") flattened and with the single-seeded spikelets closely arranged along only one side; seeds purplish-green and ridged lengthwise. Flowers from July to September.

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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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For more information:
Toll Free: 1-877-424-1300
Local: (519) 826-4047
E-mail: ag.info.omafra@ontario.ca
Author: OMAFRA Staff
Creation Date: 01 June 2000
Last Reviewed: 01 November 2003