Goldenrod Plant Profile

Don't Blame It for Fall Allergies

Goldenrod
David Beaulieu

Goldenrod is the source of mild debate in the plant world. Some say this plant is a type of wildflower, others say it is a type of weed. The answer is a matter of opinion: Whether or not you should grow it in your yard is really up to you. Goldenrod is an attractive plant only when in bloom, and its stalk and leaves have a "weedy" look. Its bloom time, depending on the type of goldenrod, extends from midsummer or late summer until the frost in cold climates. For some, the beauty provided by this flower for those two or three months is enough to earn it a spot in their wildflower garden. But weed or wildflower, goldenrod is not a source of allergens, as is commonly believed.

  • Botanical Name: Solidago canadensis
  • Common Name: Canada goldenrod, common goldenrod
  • Plant TypePerennial
  • Mature Size: 5 feet tall or more and narrow (but multiplies to become wider)
  • Sun ExposureFull sun to partial sun
  • Soil Type: Well-drained
  • Soil pH: Slightly acidic
  • Bloom Time: August to October
  • Flower Color: Golden-yellow
  • Hardiness Zones: 2 to 8
  • Native Area: North America

How to Grow Goldenrod Plant

Most types of goldenrod are native to North America, where they grow as wildflowers in pastures and along roadsides. This fact gives you a good idea of how tough they are, since the soil along roadsides is often poor. In its native region, goldenrod requires little care.

For the sake of having a tidy yard, you may wish to cut down the dead stalks in late fall and compost them. Divide and transplant in spring if you wish to increase your supply of the plant, but be warned that this plant can be aggressive. The plants often develop rounded swellings on their stems called galls. The galls are caused by insects but do not do any harm.

Light

Full sun is best. Goldenrod will tolerate a bit of shade but may not perform as well under such conditions.

Soil

The only real requirement here is good drainage. The plant even tolerates clayey soil.

Water

Water the plant moderately when young to get it established. But North American gardeners enjoy growing native plants such as goldenrod because, once mature, and if properly located in the landscape, native plants tend to need less care (including watering) than non-native plants do.

Fertilizer

Fertilizing is not necessary. But if you wish to give your plants a boost and/or increase their height, fertilize them with compost in spring.

Dealing With Goldenrod's Invasive Qualities

True to its reputation as a weed, goldenrod is an aggressive spreader that may take over an area and form a monoculture where no other plants will be able to compete with it. 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, which is a potent combination that helps account for their being invasive.

Cultivars exist that do not spread as aggressively as do their wild cousins; 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 often so that your goldenrod never quite feels "at home." Once it becomes settled, that's when it tends to start spreading.

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

Allergies

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, in most cases, is ragweed (Ambrosia spp.). Once you see what ragweed looks like, there is really no mistaking the two plants, because they look totally different from one another. Ragweed is one of the truly noxious weeds.

Attracting Wildlife

This flower is widely known as a plant that attracts butterflies. Canada goldenrod is a food source for various butterflies, including monarch, clouded sulfur, American small copper, and gray hairstreak. Goldenrod also attracts a number of other insects, including bees.

Facts About the Name

There are many species of this herbaceous perennial. The common or "Canada" goldenrod (S. canadensis) is simply one of the more widespread (and more striking) types and gets its species name from its occurrence in Canada. The flowers of S. canadensis occur in tufts, and the overall plant will occasionally grow as high as 10 feet tall, but it commonly reaches only about half that height. Despite there being many types of goldenrod, we can generalize and say that this perennial is a tall, slim plant topped off with fluffy, golden flower spikes. Thus the most likely origin of the common name is golden (for the flower color) + rod (a reference to its spindly shape).

In addition to being the common name of a wildflower, "goldenrod" is also the name of a color, describing a yellow similar to the plant's flowers.

The genus name comes from two Latin words: solidus (whole) and ago (make). This plant can "make you whole" in a medicinal sense. The name alludes to its uses as an anti-inflammatory and a diuretic. Goldenrod also was traditionally used as a so-called "vulnerary" herb, which is a plant used to promote the healing of wounds, other examples being:

Varieties

Audubon's Field Guide to New England states that there are more than a dozen species of Solidago in that region. S. canadensis is especially pretty and very common (thus the alternate name, "common goldenrod"). S. speciosa is also a handsome plant. In fact, the latter is so striking that its common name is "showy goldenrod." It grows to be 2 to 3 feet tall. Other varieties native to New England and the surrounding regions include:

  • Zigzag (S. flexicaulis): The origin of its colorful common name lies in the fact that its stem actually does zigzag. It grows to be 3 feet tall.
  • Old-field (S. nemoralis): Somewhat on the short side, by comparison, old-field goldenrod stands 2.5 feet tall. Its flower heads are more cylinder-like than tuft-like.
  • Bog or "swamp" goldenrod (S. uliginosa): As its common names suggest, this 4-foot plant performs better in areas with wet soil than most types.
  • Seaside (S. sempervirens): Just as there is a goldenrod for swampy areas, so there is a variety for the seashore. This is the kind to grow if you need a salt-tolerant plant. Its height varies greatly (1 to 8 feet tall) depending on growing conditions.
  • White goldenrod (S. bicolor): Noteworthy simply because it does not have golden-yellow flowers, this white-flowered kind grows to be 1 to 3 feet tall.