Five-percent white distilled vinegar from the grocery store will kill
henbit, a cool-season annual weed. But I think the vinegar needs to work
in conjuction with some other factor to be effective against henbit. That
factor might be warmer temps like 60 degrees plus maybe, or perhaps it's
a lot of sunlight.

I've been able to kill tons of henbit in my *back*yard with a 5 percent
white distilled vinegar spray, but when I sprayed henbit located in my
*side* yard which gets much less sun and gets lotsa shade due to the
house, the henbit would not die. I sprayed that henbit on the side of
the house 2 or 3 times on 2 or 3 different days....sprayed it heavily.
I really unloaded that vinegar into the henbit, but the henbit wouldn't
die. It looked perfectly fine days later as if vinegar never touched it.

What happened? Does vinegar need to work in conjunction with *sunlight*
to eliminate henbit? Or does the vinegar need warmer temps? I finally had
to pull out the sideyard henbit to get rid of it.

Tons of henbit got wiped out in the backyard by using vinegar but the
usually shaded sideyard henbit still looked strong and untouched. It
laughed at vinegar.

I'm not sure what the X Factor is: sunlight or warmer temps. I tend
to think it's sunlight because I believe I sprayed the side yard
during warmer temperatures.