Ontario Weeds: Canada goldenrod

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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. Caution
  9. Similar Species
  10. Related Links

Name: Canada goldenrod, Solidago canadensis L.,

Other Names: verge d'or du Canada, bouquets jaunes, solidage du Canada, verge d'or

Family: Composite or Aster Family (Compostiae

General Description: Perennial, reproducing by rhizomes and by seed.

Photos and Pictures

Canada goldenrod. Flower

Canada goldenrod. A. Underground rhizome having produced 2 aboveground shoots. B. Top of flowering stem.
Canada goldenrod. A. Underground rhizome having produced
2 aboveground shoots. B. Top of flowering stem.

Stems & Roots: Stems 20-200cm (8-80in.) high, branching only in the upper part, hairless near the base, densely but very finely pubescent toward the top; leaves numerous, stalkless, sometimes crowded, 1-15cm (2/5-6in.) long and 1-22mm (1/25-7/8in.) wide, lanceolate, tapering to both ends; margins vary from nearly entire to usually having fine or sometimes coarse, widely-spaced teeth; most leaves with one prominent midvein on the undersurface and two distinct lateral veins that branch from it and parallel it nearly to the tip of the leaf; lower and middle stem leaves of plants in thick patches usually dying and falling off by flowering time.

Flowers & Fruit: Inflorescence a broad or occasionally narrow pyramidal panicle 5-40cm (2-16in.) high and nearly as wide, with several to many horizontal branches, the upper sides of which carry numerous, densely-crowded small heads of golden yellow flowers; each individual flower head about 3mm (1/8in.) long and wide. Flowers from mid-July to September.

Habitat: Canada goldenrod is a native plant that is found throughout Ontario in moist or dry fields and meadows, edges of forests, swamps, clearings, orchards and compost piles, and along roadsides, ponds, streams, fencerows and shorelines, and recently as a weed in cultivated fields.

Caution: Goldenrod is commonly accused of being the cause of hay fever allergies for many people. But it is innocent. Goldenrod is insect-pollinated and its heavy and slightly sticky pollen does not blow on the wind. Ragweed is the usual culprit, but it has inconspicuous flowers whereas Goldenrod, which flowers at the same time, has highly conspicuous flowers and gets the blame.

Similar Species: It is distinguished by its creeping rhizomes, its relatively narrow leaves that are widest in the middle and taper to both ends, have two lateral veins parallelling the prominent midvein and usually have widely-spaced fine to coarse teeth, and by its usually broad, pyramidal panicle.

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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