If you used plain old Roundup, it may have had no surfactant in it, thus causing a poorer result than a similar product. Most of these new 41% Roundup offshoot products now have the sticker/spreader pre mixed for best results. The Roundup Max (I think that's the one) is a 48% Glyphosate product with surfactant. I use more Big & Tough from Tractor Supply than anything though, $59 for 2.5 gallons of concentrate.