Goldenrod Weeds

These Wildflowers Invasive, but Not the Cause of Allergies

Goldenrod (image) is not only breathtaking when in bloom but also not a health hazard.
Think goldenrod is the source of your hay fever? Think again!. David Beaulieu

Taxonomy and Botany of Goldenrod

Plant taxonomy classifies goldenrod in the genus, Solidago. Many species exist; Audubon's Field Guide to New England states that there are more than a dozen in that region. One of the more widespread -- and more striking -- types of this flower is common or "Canada" goldenrod plant (Solidago canadensis).

Goldenrod is an herbaceous perennial.

Characteristics, Care

In addition to being the name of a wildflower, "goldenrod" is also the name of a color, defined as "a strong to vivid yellow." You need search no further for the defining characteristic of this plant, whose flower stalks bristle with numerous small flowers of a vivid yellow or gold.

Although there are many types of goldenrod flowers, this perennial is, generally speaking, a tall, slim plant (4-5 feet for some types) topped off with fluffy, golden flower spikes. Thus the most likely derivation of the common name: golden (for the flower color) + rod (a reference to its spindly shape).

Most types are indigenous to North America, where they grow as wildflowers in pastures and along roadsides. There are goldenrods as far north as zone 2 and as far south as at least zone 8.

In its native region, it requires little care. For aesthetic purposes, cut down the dead stalks in late fall and compost them. Divide and transplant in spring if you wish to propagate (but see below about the plant's aggressiveness).

What Are Some Warnings About Growing Goldenrod? Does It Cause Allergies?

A warning about growing this weed is that it is an aggressive spreader that may take over an area and form a monoculture.

This wildflower may thus be considered an invasive plant outside its native range. The plants spread not only by reseeding, but also via underground rhizomes -- a potent combination that helps account for their being invasive.

Fortunately, one warning that you will hear concerning this flower is mainly a myth.

People who speak of "goldenrod allergy" are usually guilty of blaming the wrong weed for their hay fever, the real culprit being ragweed. Does this fact make you curious enough to ask what ragweed looks like?

Growing Goldenrod

"Weed" or not (the designation is subjective), many gardeners are interested in growing this plant, since it has such lovely flowers. Goldenrod will perform best in full to partial sun and a well-drained soil, but these wild plants will also tolerate clay. Cultivars exist that don't spread as aggressively as do their wild counterparts; one is 'Crown of Rays.'

If you grow a wild version, one way to check the spread of its rhizomes is by using bamboo barriers. Another way (if you have just a small number of the plants) is to transplant frequently, so that your goldenrod never quite feels "at home."

To keep goldenrod flowers from reseeding, cut off the flower heads before seeds develop. Since goldenrod plants have stiff stems, it's easy to use them in flower arrangements.

Medicinal Uses 

Medicinal usage traditionally has ranged from anti-inflammatory to diuretic uses. It was also used as a vulnerary herb (i.e., a plant used to promote the healing of wounds), as were sweet woodruff and yarrow.

In fact, its function as a vulnerary accounts for the genus name, Solidago, which derives from the Latin solidare (meaning "strengthen" or "make whole").

Is It a "Wildflower" or a "Weed"?

Should this flower be considered a "type of wildflower" or "type of weed? Since the distinction is subjective, the answer is really up to you. It is an attractive plant only when in bloom; its stalk and leaves have a "weedy" appearance. Bloom time, depending on the type of goldenrod, is from mid-summer or late summer until frost in cold climates. For some, the beauty provided by this flower for those two or three months is sufficient to earn it a spot in their wildflower garden.

Wildlife Attracted to Goldenrod

This flower is widely known as a plant that attracts butterflies. Canada goldenrod is a food source for the following butterflies:

  1. Monarch
  2. Clouded sulfur
  3. American small copper
  4. Gray hairstreak

Goldenrod attracts a number of other insects, too, including bees.

Aster Family

Goldenrod plants are in the aster family. A huge family of flowering plants, the aster family includes not only plants with "aster" in their names (such as New England aster), but many other plants, too; for example:

  1. Chicory
  2. Dusty miller
  3. Joe-Pye weed
  4. Liatris
  5. Black-eyed Susan
  6. Blanket flower