Jay from Tx writes
On a St Augustine lawn
Nufarm Weedar 64 is not labeled for use on St. Augustine grass or for residential lawns. You may be able to use a product like Hi-Yield 2, 4-D Selective Weed Killer instead. It is a selective, post-emergent herbicide which controls dozens of broadleaf weeds and is safe to use on St. Augustine grass.
Answer last updated on: 04/02/2019