At the very least, weeds can ruin the look that gardeners wish to have in their gardens. However, at their worst, weeds can sap the valuable nutrients that keep a gardener’s favorite plants alive. Many gardeners rush to the store to find herbicides that will kill off the troublesome weeds. These herbicides can be very helpful if used correctly, but can also kill some plants unintentionally.
Killing Weeds
Herbicides are used either to kill certain species of plant or to manage these plants. Gardeners might want to get rid of a certain species of plant because this plant is no longer desirable, though the plant might be very difficult to get rid of, according to Science Encyclopedia. Herbicides are also used to get rid of weeds that can sap nutrients, light and water away from other plants.
Improving Agricultural Yields
Herbicides are essential in some forms of agriculture, since weeds dramatically reduce crop yields, according to Science Encyclopedia. Herbicides are also a time saver, since they are faster than pulling weeds by hand or cutting weeds. In some cases, pulling weeds can even cause the pulled weeds to propagate, according to Colorado State.
Spraying
Herbicides are usually sprayed on to the plants that are intended to be killed or are soaked into the soil, according to Science Encyclopedia. Herbicides are chosen based on the kinds of weeds that need to be killed and based on the plants that the gardener does not want to kill. Whether or not weeds are annual or perennial plays a role in the herbicide used, since some herbicides work by interfering with the plant’s ability to reproduce and annuals that cannot reproduce will not come back the following year.
Selective Killing
Herbicides are often chemicals that damage some plants while not damaging others, so that undesired plants can be wiped out. Other chemicals cause growth abnormalities in the plants which cause them to die. Some herbicides are taken up into the plant’s stems and interfere with the plant’s ability to synthesize amino acids. Those types of herbicides are often preferable because they do not harm animals as often, but they can sometimes kill plants unintentionally if they’re administered to plants when they are vulnerable, according to Science Encyclopedia. The crops are sometimes genetically altered in order to make them resistant to the herbicides.
Broad-Leaf Killing
Broad-leaved weed killers can damage or kill trees if they seep into the soil and are absorbed by the roots, so they should be used sparingly, according to Colorado State. The broad-leaf weed killers also often kill plants in vegetable gardens. Some herbicides can only be used by certified commercial applicators because they can accidentally damage the trees of neighbors.
Reference
http://www.coopext.colostate.edu/4dmg/Weed/herbicid.htm
http://science.jrank.org/pages/3306/Herbicides.html