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Season-Long Grass & Weed Killer

By Jonathan Budzinski ; Updated September 21, 2017
Long grass and weeds steal  the nutrients and deplete the soil.
long grass image by Nikon'as from Fotolia.com

Season-long grass and weed killers kill weeds and prevent weed growth for a full season. They are available for both perennial and annual weed control. Using season weed killers may save you both time and energy in weed elimination. It is important to identify the weed before choosing which herbicide will work best for you.

Weed Identification

There are two main types of weeds: annual and perennial. Perennial weeds return each year after dormancy. Annual weeds will die once the weather no longer permits their growth. Common annual weeds include crabgrass, garlic mustard, wild radish and corn marigold. Some weeds that return each year are nimblewill, Kentucky bluegrass and tall fescue. Identifying the type of weed attacking your lawn is the first step in fighting back.

Preemergent Herbicides

Season-long grass and weed killers are sold as either preemergents or postemergents and only require application once per season. Preemergent herbicides are specifically formulated to prevent seeds from germinating. These should be used early in the spring while warm-season grasses are still dormant. This will help stop infestations before they can spread. Applying season-long weed killer in the fall is better for preventing the growth of broad-leaf weeds, which sprout later in the year.

Postemergent Herbicides

Postemergent season-long herbicides are made to destroy weed plants after they have broken the surface. Perennial weeds generally do not respond to this type of herbicide and will often regrow multiple times during the same growing season.

Herbicide Types

Season-long grass and weed killers are available in both granular and liquid forms. Solid herbicides release their chemicals into the ground slowly, usually during rainfall or watering, and are easier to control. Liquid herbicides activate quickly but are more likely to reach unnecessary parts of the garden. Never use liquid herbicides when it's windy or rainy as this can quickly lead to runoff, which can damage nearby environments.

Lawn Care

Weeds are often a sign of unhealthy lawn practices. Maintaining a healthy lawn will help protect it from weeds. Lawns and gardens require frequent fertilization to avoid nutrient deficiencies which weaken root systems and allow for weed growth. Over-watering your plants will also promote unwanted plant growth, so water carefully.


About the Author


Jonathan Budzinski started his writing career in 2007. His work appears on websites such as WordGigs. Budzinski specializes in nonprofit topics as he spent two years working with Basic Rights Oregon and WomanSpace. He has received recognition as a Shining Star Talent Scholar in English while studying English at the University of Oregon.