Ontario Weeds: Canada goldenrod
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Excerpt from Publication 505, Ontario Weeds, Order this publication
Table of Contents
- Name
- Other Names
- Family
- General Description
- Stems and Roots
- Flowers and Fruit
- Habitat
- Caution
- Similar Species
- 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.
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
For more information:
Toll Free: 1-877-424-1300
E-mail: ag.info.omafra@ontario.ca