Question of the Week Number Three: April 22, 2021

“I’m having trouble getting rid of these two weeds. What are they, and how can I eliminate them?”

These two weeds have several things in common:

They’re both broadleafed weeds. That essentially just means that they’re not grasses. You can pretty well tell that just by looking at them.

But conventional broadleafed weedkillers (containing 2,4-D) don’t always work very well at stopping them.

Here’s a tip that should help…
These plants both have built-in mechanisms for shedding herbicide sprays.

These wild violets are pretty enough to cultivate. But the man who posted this photo on my Facebook page had other desires for this part of his landscape.

Wild violets have funnel-shaped leaves. Sprays bead up and roll off without sticking.

All of our cultivated plants should be this attractive. But dollarweed never seems to grow where we want it!

Dollarweed has extremely glossy leaf surfaces. Sprays bead up and roll off without sticking.

See anything common to those two statements?

If we could figure out a way to prevent the sprays from beading up and rolling off, we’d have it made. And that’s where one drop of liquid dishwashing detergent enters the picture. It cuts the surface tension on the glossy leaves, and it allows the spray to coat the leaves of the funnel-shaped foliage.

Bingo! We have a solution.

Our only remaining challenge is to apply the spray in droplets small enough that they don’t hit like they came out of a water cannon. That’s why I suggest either a hand spray bottle with a trigger or a 1- or 2-gallon tank sprayer. Either of those options can be adjusted to apply fine droplets that coat the surfaces much as your hair and clothes are coated when you walk out into a misty rain.

Continued Below

Read and follow label directions regarding temperature, mowing before and after you treat, irrigation and rainfall, etc. for the best results.

Do all of this (fairly simple if you think about it) and put your best patience to work. It takes broadleafed weedkillers several days to start showing their effects, and with these two weeds, several sprays over a 6- or 8-week period may be required.

Posted by Neil Sperry
Back To Top