Foliar spraying

Here, the herbicide is diluted with water or another diluent as specified on the product label, and sprayed over the foliage to point of runoff (until every leaf is wetted, but not dripping).

The method is most suited to shrubs, grasses and dense vines less than 6 m tall so that complete coverage is achieved. Advantages include speed and economy. Disadvantages include the potential for spray drift and off-target damage.
Foliar spraying can be done in a number of ways, depending on the size of the weed plant or the infestation. Blanket spraying, using a boom spray from a tractor or aircraft, can be used to treat areas completely infested with weeds, especially with selective herbicides.

For large infestations that need targeted applications of herbicide, a hose and handgun can be used to spray solution from a herbicide tank and pump carried by a tractor or vehicle. Smaller infestations can be sprayed using a backpack/knapsack spray unit. Spot spraying is used to treat individual weed plants or areas that only have small clumps of weed infestations.