“What is the greatest gift? …something else – something else entirely holds me in thrall. That you have a life that I wonder about…” Mary Oliver
I want to update our methods of keeping Canada goldenrod (Solidago canadensis) in check. At right is a beautiful specimen surrounded by a diversity of other prairie plants (photo by Sandy Stark).
Some managers use a mowing or cutting schedule, either twice yearly or once a year when the plants are flowering. Tom in his blog said mowing does not eradicate the goldenrod clones, but trichlopyr (20% garlon 4) does (August 31, 2011). He described a “spritz” technique for killing the plants using a spray bottle of garlon 4 to very sparingly spritz just a few upper leaves. Alternatively, Canada goldenrod can be cut, leaving a 12 inch stem that is then dabbed or sprayed with garlon 4. We’ve found this latter method to be less messy in that walking through and around treated plants leaves fewer drips on our clothing.
The past five years or so we have been experimenting with two methods of Canada goldenrod control. The first is to simply cut the stems in a flowering clone with a hedge shears once a year, not treating with herbicide, and repeating the cutting in subsequent years. This is followed by burning yearly or every other year and then seeding with a mix collected from adjacent areas. Seeds include but are not limited to woodland goldenrods, asters, black- and brown-eyed Susan’s, golden Alexander, ox-eye sunflower, monarda, showy goldenrod, hyssop, tall bellflower, milkweeds, savanna grasses, native thistles, bonesets, stiff gentian, and more, all generally fast-growing prairie or savanna species. Wet-mesic species go into areas where the goldenrod is growing near the marsh. These include lousewort (see below), Culver’s root, cup plant, mountain mint, dark-green bullrush, wool grass, meadow rue, gentians, great blue lobelia. The rationale here is that herbicide, however carefully applied, always damages adjacent plants, eliminating competition. In subsequent years, therefore, the goldenrod may rebound (see Chris Helzer – Prairieecologist.com/2011/08/19 – for support). “Over seeding is a must,” and, to paraphrase, the vegetative spread of goldenrods increases with disturbance (Driftlessprairie.org). The Driftless Prairie managers also stress that goldenrod control be “multi-pronged” and will take years. But they crucially remind us that this species sustains scores of important insects, so total elimination should not be a goal. For us, this method has so far resulted in shorter, fewer and less robust goldenrod plants over the patient years.
Our second method of Canada goldenrod control is exactly the same as the first, with the addition of seeding the goldenrod clone areas with wood betony (Pedicularis canadensis) either shortly after collecting the seed, later in the season, or after spring burns. At left is a wood betony specimen in flower (photo by Amanda Budyak).
