Bermuda grass, annual bluegrass, and crabgrass are some common narrowleaf weeds. Controlling Weeds Pulling lawn weeds by hand can be a tiresome, overwhelming, and usually a futile job. The most effective way to remove exiting weeds is to apply a chemical weed control formulated for your variety of grass. Both annual and perennial weeds are most vulnerable at the seedling stage, so herbicides are most effective when applied to young, tender weeds. Here are some guidelines to observe when applying herbicides to your lawn.
Herbicides generally work best on young, succulent annual weeds, such as crabgrass.
The weeds should be actively growing at the time of application to ensure that they absorb the material efficiently. Perennial weeds, such as dandelions, are more sensitive to herbicides late in the growing season when food moves downward to replace those reserves. At this time the herbicide is readily carried throughout the plant and is most effective. For maximum effectiveness, use herbicides when the soil is moist and warm. These conditions favor the most rapid growth of weeds, and hence the most efficient uptake of herbicides.