Weedmaster

Last spring the buttercups were taking over the hay field badly so I sprayed sometime around the middle of April and baled May 6. I was very happy with how weedmaster worked. Two weeks ago I sprayed weedmaster when I saw the first buttercups coming up. I have not really seen the chickweed die out like it did with the buttercups last year. I sprayed the same rate as last year. Does weedmaster work better in hotter temperatures? Just trying to figure out what’s going on. Thanks

Weedmaster