Weed & Stump Killers

Overview

Every plant has the potential to be labeled as a weed. The definition of weed is any plant unwanted in a particular garden or natural setting. If the intent was to establish an acre of sunflowers and suddenly a wild rose is blooming beautifully, but not as planned, it would be labeled a weed. There are four categories of herbicides to help remove those painful, thorny pests.

Pre-Emergent Herbicide

A pre-emergent is easy to remember; the prefix says it all, it is a chemical that will target weed seeds and stop them from emerging. This is a useful product when planting a new garden or even keeping weeds out of a newly top-dressed garden or plant border. A pre-emergent should be applied in the spring when the possibility of rain is highest. Rain will activate the chemical and spread it throughout the garden soil. Local garden centers carry pre-emergent herbicides in many brand names; the most common one is Preen. In the landscape maintenance and plant nursery industries, Surflan is commonly used to control the emergence of weeds in container-grown plants.

Post Emergent Herbicide

A post emergent herbicide is the opposite of a pre-emergent; it will kill weeds after they have emerged and are steadily growing. They are often used to kill established grasses and broad leaf weeds growing in plant beds. Some post emergents target young vigorous plants and others target particular broad-leaf weeds. It is important to identify the targeted weed to establish an effective control. Certain post emergents only kill grasses and others only broad leaf and woody plants. Most post emergents neutralize on contact with soil, which is safe for ground water, wildlife and adjacent water ways. Active ingredients may include clethodim, fluazifop and sethoxydim. Read labels carefully and apply only as directed by the manufacturer; to do otherwise is unlawful.

Non-Selective Herbicide

A non-selective herbicide is not finicky about what type of plant it will kill. If it's green and growing it will be damaged or eliminated as the product is absorbed from the leaf pores down to the root system. Younger plants will be more susceptible to this product because of their vigorous growth habits, so spring application is best. There are are some plants that are becoming immune to the effects of non-selective herbicides because certain species have genetically modified resistance in their seeds. Products in this classification use an active ingredient called glyphosate, which is also known by the brand names Round-Up, Rodeo and Prosecutor.

Vegetation Control Herbicide

Vegetation control herbicides must be used with utmost care and attention because they will kill any plant at any stage of life, and unlike non-selective herbicides this product can leach into soils and has the potential for contaminating waterways and ground water. It's best to be conservative when using such a powerful herbicide. Commonly, this is the type of herbicide applied to newly cut tree stumps to inhibit sucker growth and to completely kill plant roots. Brand names vary and there are many of this classification on the market. It's wise to read product labels and use exactly as directed.

Certified and Licensed Application

In home use it's fine to use chemical controls as indicated on the product label, but in a commercial setting an applicator must be certified to spray certain herbicides. The company selling the product must be licensed to purchase and resell the chemicals to wholesale or even retail customers. Never use a chemical on a neighbor's lawn or spray near open waterways. Many herbicides can harm wildlife, aquatic life and even pets; always keep these products out of the hands and reach of children.