We found an effective treatment method for Canada goldenrod that works very well for small areas and reduce collateral damage to virtually nil. Once an area is treated, it helps to overseed the area. Give it a year or two before you burn or mow the area. These disturbances the following year stimulate the Canada goldenrod.
Our goal is to minimize the amount of Canada goldenrod we have. We have no illusion that we will ever eradicate it!
The Technique
We use a 20% glyphosate solution (in water) and cut the flowering Canada goldenrod about waist high then dabbed the cut stems with the herbicide soaked trim brush.
By using a painting trim brush (one that is not a sponge) and a tallish container for the herbicide, we found we could gather enough herbicide in the brush without dripping it. Tap this on the cut end and it has complete coverage without dripping – no dripping down the stem and no dripping from the herbicide container to the cut end! We used a tallish container so the brush would stand upright and the handle would not slip down into the herbicide.
Canada goldenrod dead after a month
On August 17, 2013, we did a test in a small area to see how this would work. Within a week, we were seeing results. On September 4, 2013, this is how one of those test patches looks! You can see from this picture that we would have had a lot of collateral damage with the spritzing method.
The results show this system works and minimizes collateral damage!This technique can work for a person working alone. Using a fanny pack, I was able to find a tallish screw-lid glass jar that would fit in it. I had to cut the handle of the trim brush slightly to fit inside the jar. When I wasn’t cutting, the herbicide and the trim brush were secure in the fanny pack with the lid on.
Results after one year
Here’s a couple of photos I took on 30 July 2014 of the area that was thick with Canada Goldenrod. As you can see, there is no Canada Goldenrod!
Our analysis is that this treatment worked. Best of all, it’s minimal effort, minimal herbicide, and minimal collateral damage.
Why we use dabbing and not spraying
Let me describe our process of arriving at this treatment. We tried cutting it with a handheld pair of hedge trimmers then spraying it with a 20% glyphosate solution but the spray caused too much collateral damage. We thought we could minimize this by surrounding the Canada goldenrod clones with cardboard and just lightly spritzing the tips with a downward angle on the bottle but you can see from the picture how much overspray occurs. I would not recommend this type of treatment.
At Lakeshore State Park we had almost total goldenrod removal by spot spraying goldenrod with Element 4 very late in the fall – so late that many of the goldenrod plants had dropped half their leaves by the time we sprayed, with the remaining leaves a deep red color. Most desirable plants were dormant at the time of spaying. In one of the smaller prairie plants where goldenrod dominated, this technique resulted in a 99+ % reduction the following year, with no goldenrod recovery for the two years since. Forbs we had planted 5 years previously in the prairie but had not seen since the goldenrod took over rebounded after the goldenrod was removed. We had similar success in a larger prairie area where goldenrod also dominated.
Thanks for that info! We had that rebound of diversity as well. One other addition I need to make to this article is 2 years after we did the first treatment, we burned. Since fire stimulates goldenrod, we did another treatment.
Hello! Thank you for this article and the reply. I am curious Tom, what concentration of Element 4 you used when you sprayed the goldenrod late in the fall? Thanks!
Brittany,
Usually Element 4 or we use Progeny brand is a 20% mix (if I recall correctly). It’s 64 oz of herbicide to 2 gal of bark oil.
Marci
I have been cutting and treating unwanted goldenrod stems with the Buckthorn Blaster herbicide applicator. No herbicide drift, no herbicide waste. Awesome results.
We’ve used that as well. It works great on the stiffer stems but we found it hard to use on the smaller diameter stems. It’s the same issue with the system we’ve been using with the trim brush. Using a spray bottle works well on those less stiff stems or the ones without blooms. We’ll do a half squirt with the nozzle touching or nearly touching the top.
Does it make sense to spread a pre-emergent in the spring to help control spread of Golden Rod due to seed spread?
No. We don’t use pre-emergents with native ecosystems. They would repress any broadleaf wanting to come up. Ideally, we want other natives to take over the Canada goldenrod clones to reduce them and out compete them.
We have areas that are much too large to make individual spraying feasible (i.e, it would take lots of people a lot of time, and we have neither). We have had pretty good luck by mowing in mid-June when the new stalks have gotten a couple feet high. That mowing seems to hit them hard enough that they never get tall again over the summer, and other things can grow up through and get established. If we do this in an area with lots of goldenrod for a couple years in a row, they mostly go away. It’s not the quick fix that we all love, but it does seem to work provided there are other things there to compete.
Andy — Good to have that info added. The method I describe would certainly not apply to large areas. And I’m sooo glad to know the timing for the mowing.
Thank you…how high do you set your mower?
Caution: Keep in mind that mid-June is the peak season for nesting grassland birds – the most imperiled group of birds in North America with around 50% population declines in recent decades. We have been mowing late July, when the flowers are forming. Almost a solid monoculture so little concern for other species. May be able to follow that with a fall herbicide on the resprouts.
Where do you find that brush? Can you show a photo of it outside of the plastic? What material is it made of?
Sue — We have purchased the brush at Ace Hardware but I imagine another hardware store might have something similar.
Do you have any insight on whether the herbicide (Roundup) gets down and kills off the massive roots on Goldenrod? I have a very small prairie area that’s being taken over and the root systems are incredibly complex. On a similar note, these grow via rhizomes as well correct? If an herbicide is used does any part of the plant need to be removed? I see many people mow as a method of control but I thought that may even increase the spread?
My original method of cut dab used 20% glyphosate mixture. The weak link in that are the younger stems that weren’t in bloom. The dabbing method doesn’t work on those. So while we could get a good portion of the clone killed with the glyphosate, the next time we mowed or burned (essentially disturbed the area), those untreated took off. We changed our system to cut and spritz and when we did that, we switched to Progeny in bark oil. This was also about the time we quit using glyphosate altogether because we didn’t find it was very effective. Yes, Canada goldenrod grows via rhizomes. We didn’t find any part of the plant needed to be removed.
Mowing at the wrong time will increase its growth. If you mowed when in bloom, the energy has been spent creating the bloom so reserves are low in the roots. Mowing when its in bloom can damage other natives in the area as well so you’ll need to consider this.
When we treat our C Goldenrod, we additionally overseed the area we have treated. This has proven pretty effective. You’ll need to consider this with the goldenrod has been growing there for a while. Some of the nice natives may have been crowded out.