Culture
Easily grown in average, slightly acidic, moderately rich, well-drained soils in full sun. Tolerates light shade. Intolerant of full shade. This is a rhizomatous, spreading, somewhat weedy plant that can rapidly colonize an area by creeping rhizomes and self-seeding. Removal of flower heads prior to ripening of seed, if practicable, will help prevent seed dispersal.
Noteworthy Characteristics
Solidago canadensis, commonly called Canadian goldenrod, is a rhizomatous, upright perennial of the sunflower family. It is native to North America (throughout Canada and the U. S., except absent from South Carolina, Georgia, Florida, Alabama, Louisiana and Hawaii). It is mostly found growing in moist conditions on abandoned farmlands, pastures, fields, thickets, prairies, waste areas and along roadsides.
Central stems are clad with numerous, narrow, alternate, lance-shaped, sharply-toothed, stalkless to short-stalked green leaves (to 6" long and 1" wide) which are hairless above but hairy beneath and tapered at each end. Central stems are hairless near the base but soft hairy above the middle. Central stems rise to 4-5' (less frequently to 7') tall and are topped in late summer to fall (August to October) with large horizontally branched terminal pyramidal panicles containing one-sided recurving branches filled with masses of tiny yellow flowers (each to 1/8").
Canadian goldenrod is considered to be invasive in many parts of Europe (introduced in 1645) and China (introduced in 1930) where it has escaped gardens and rapidly naturalized in a number of locations.
Goldenrods are attractive to bees and butterflies. Goldenrods have been wrongfully accused of causing hay fever which is actually an allergic reaction to wind-borne pollen from other plants such as ragweed.
Genus name comes from the Latin words solidus meaning whole and ago meaning to make in reference to the medicinal healing properties of some species plants.
Specific epithet is in reference to the Canadian native habitat of this species.
Problems
No serious insect or disease problems. Susceptible to rust, powdery mildew and leaf spot. Root rot may occur in poorly drained soils. Potential insect pests include several different types of beetles, aphids and gall-forming insects. Plants can be aggressive spreaders in optimum growing conditions, but are generally not considered to be invasive in the U.S.
Uses
Typically not planted in garden settings because of its spreading rhizomatous growth. Plants grow as somewhat unexceptional mounds of green foliage until the flowers explode into bloom in late summer. Naturalize in meadows.