Mark VanGessel, Extension Weed Specialist; email@example.com
Grape hyacinth has been showing up in no-till fields in Sussex County. The biggest problem with grape hyacinth is in soybeans, because it interferes with soybean harvest. It emerges in the fall and can grow to 8 – 10 inches tall. If the infestation is severe, the waxy succulent leaves will interfere with the cutter bar. We do not have a lot of experience with grape hyacinth at this point, but it appears that glyphosate at 1.5 times the normal rate is the best treatment (1.12 lbs acid equivalent per acre). Last spring we compared glyphosate at normal and 1.5 X rates, and included paraquat; both tank mixed with Canopy EX. The treatment that provided the best grape hyacinth control in the fall was the higher rate of glyphosate. Glyphosate in the spring was slow to kill the grape hyacinth; but in the fall, the number of stems was significantly lower and the plants were smaller. As with all perennials, one year of an aggressive treatment will really help, but it requires more than one year to “clean up” the field.