Goldenrod – Great in the Garden (with some exceptions): how to tell the beneficial from the problematic

In September, the star of the garden is Goldenrod, along with its traditional companion, Aster. Goldenrod is a keystone plant which supports a large variety of wildlife. There are 22 species of goldenrod (mostly in the genus Solidago and Oligoneuron) that are considered native to the Chicago region.

Despite its beauty and wildlife value, there are a couple of reasons people may be reluctant to include Goldenrod in their gardens. Many people mistakenly believe Goldenrod causes hay fever, which we talked about more in depth in our last post. Another reason is that the Goldenrod we see most often are tall, floppy and aggressive species which seed themselves into our ornamental garden beds, or colonize vacant lots, alleyways, and drainage ditches.

There are three species that often cause trouble: Canada Goldenrod (Solidago canadensis), Tall Goldenrod (Solidago altissima), and Late Goldenrod (Solidago gigantea). These aggressive species are native, and are very beneficial to pollinators, but they do not play well with others in the garden. Their role in the North American ecosystem is to fill in gaps created by soil disturbance. In the last 200 years, soil disturbance has become the norm rather than the exception, and now the species that evolved to fill this niche can sometimes hinder our efforts to restore plant biodiversity. We recommend either removing them from your garden in favor of other goldenrod species, or else keeping a patch in check by making sure it doesn’t spread by rhizome (horizontal underground stems) or seeds disbursed by wind. These three plants have subtle differences between them, but they also have a few things in common that help us identify them. They have tall, usually unbranched stems, and long, narrow, slightly toothed leaves that have three prominent parallel veins that can be seen and felt on the back side of the leaf. The Field Museum has these troublesome goldenrods described in “Group 3” in their 2011 guide to Goldenrod. (Note that the flat-top Goldenrods in Group 1 of this guide have since been reclassified as the genus Oligoneuron)