atrazine
Conifers only including Douglas-fir, grand fir, noble fir, Sitka spruce, and pine
Rate 2 to 4 lb ai/A
Time Apply October through March when trees are dormant.
Remarks Can be applied after small weeds emerge. Requires rain or sprinkler irrigation to activate. Apply only once per year.
Caution A restricted-use pesticide.
Site of action Group 5: photosystem II inhibitor
Chemical family Triazine
oxyfluorfen (Goaltender)
Rate 0.5 to 2 lb ai/A (1 to 4 pints/A)
Time Apply to deciduous, field-grown shade trees listed on label; direct the applications toward the soil and tree base. Apply to 2-0 conifers in winter dormancy fall through winter. After transplanting, irrigate with 0.5 to 0.75 inch of water or rain for preemergence control of annual grass and broadleaf weeds. Do not exceed 2 lb ai/A per year.
Remarks Postemergence applications control susceptible broadleaf weeds up to 4 inches tall. Goaltender is a contact herbicide. It inhibits cell division (mitosis) in roots and shoots.
Site of action Group 14: protoporphyrinogen oxidase inhibitor
Chemical family Diphenylether