herbicide

We did a cut and treat method in the fall of 2013 after the Canada Goldenrod (Solidago canadensis) had bloomed. It appeared to be successful after a weeks when we could see the plants were dying but the real test was what would happen a year later. You can check out the original blog post. [Read more…] about Treating Canada Goldenrod – Follow Up

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.