Herbicides are chemical substances applied to plants and soil to prevent growth of and kill weeds and other invasive plants. Unless otherwise noted as organic or natural, herbicides are synthesized by humans. A vast array of options spans the wide spectrum of invasive weeds and plants that compete with garden plants and food crops. Identify different herbicides and the invasive plants they control.
Glyphosate is a very commonly used herbicide, according to the University of Florida IFAS Extension. When invasive plants infest your garden, glyphosate is applied to foliage as a means of killing the plants for control of subsequent problems. When applied, this plant herbicide inhibits normal plant function; glyphosate ceases growth of amino acids that are necessary for development of enzymes and proteins within the plant. This herbicide is nonselective, meaning it will injure or kill plants other than the plant in need of control if contact occurs. Apply carefully to avoid damaging other plants. Glyphosate will not provide effective control when applied to soil. Plants controlled by glyphosate include, but are not limited to, barnyardgrass (Echinochloa crus-galli), annual bluegrass (Poa annua), chickweed (Stellaria media) and yellow foxtail (Setaria glauca), according to the University of California Cooperative Extension.
Triclopyr is another commonly applied herbicide for plants. This chemical controls certain weeds, brush and trees. Triclopyr kills and controls invasive plants and is generally sprayed on the plant. Like glyphosate, triclopyr does not continue for extended periods when incorporated in soil, according to the University of Florida IFAS Extension. Triclopyr affects plants by causing hormonal imbalances in plants, thereby ruining their ability to function normally. Some of the weeds effectively controlled by triclopyr include clover (Medicago and Melilotus species), dandelion (Taraxacum officinale) and pigweed (Amaranthus species), according to the University of California Cooperative Extension.
Imazapyr is a widely used herbicide for invasive plant management, according to the University of Florida IFAS Extension. Imazapyr is applied to plant foliage, but it also remains active in soil and continues to work by absorption through plant roots. A drawback to herbicides that remain active in soil is the potential for damage to nearby plants that are non-invasive. This herbicide acts similarly to glyphosate whereby it inhibits the development of amino acids within the plant. However, imazapyr does not affect the same amino acids as those altered by glyphosate. Weeds controlled by this plant herbicide are cocklebur (Xanthium strumarium), goosegrass (Eleusine indica), lovegrass (Eragrostis cilianensis) and wild oat (Avenuea fatua), according to the University of California Cooperative Extension.