Goldenrod vs. ragweed: Which causes allergies and which benefits pollinators?
A field of showy golden flowers is a common site in late summer, but is goldenrod to blame for our allergies?
Many people suffer from allergies in mid- to late-summer, but few know exactly what causes them.
Goldenrod, a prolific flowering plant with masses of golden flowers, is often blamed for the itchy eyes, runny nose, and other symptoms that many of us suffer from during summer allergy season. However, for most of us, ragweed pollen is the true culprit. While goldenrod actually benefits butterflies, bees and other pollinators.
We write about this every couple of years. Here's an article from 2015 on how to tell the difference between goldenrod and ragweed, and why ragweed is the big contributor to allergy season. (In short, goldenrod's pollen is too large to fall far from the plant, but ragweed's tiny, light pollen travels widely.) Still, goldenrod continues to get a bad rap.
Goldenrod has a reputation as an invasive plant, which can be true depending on the habitat and the circumstance. It’s a common native species that provides a great late-season resource for pollinators, but it can be quite aggressive. So much so that it can crowd out other native prairie and savanna species to form a monoculture, creating a field of only goldenrod plants.
This is especially true when there’s a lack of management or an abundance of resources, including space or nutrients. However, with proper management, goldenrod can be an important part of our natural areas, and at FMR we often include one or more goldenrod species in our prairie and savanna restorations.
While Canada goldenrod may be the most common and recognized species in Minnesota, we frequently include species like stiff goldenrod (Solidago ridiga [pictured below]) and old field goldenrod (Solidago nemoralis) in our grassland restorations.
Even our forest restorations often include a goldenrod species (zig-zag goldenrod; Solidago flexicaulis). But those are just a few of the roughly 45 species of goldenrod in the state.
Monarch butterflies on stiff goldenrod (Solidago rigida) at Coldwater Spring.
So just remember that these yellow flowers you see across urban, suburban, rural and natural landscapes are great plants for pollinators, and aren't likely contributing to your allergies or your neighbors'.
If you'd like to make sure you're not removing goldenrods when you mean to be getting rid of allergy-triggering ragweed, check out our article on the differences between these plants.