What is a Weed?
The name “weed” has usually been associated with plants, both native and of foreign origin, that are not desirable. From the agronomic standpoint, a weed is described as “a plant that can cause economic loss in a production unit.” Many gardeners and home landscape managers view a weed as a “plant growing out of place.” Still others view a weed as a “plant whose virtue has yet to be discovered.”
Weeds are often invaders. Weeds are part of the natural process known as plant succession. Weed species both herbaceous and grass species are some of the earliest pioneer plants that appear over time in newly developing soils. Weeds can withstand long periods of drought and grow where little soil exists. Weeds also produce an abundance of seeds for continuing the future life of the species.
Weeds are seen in different eyes. Form most, weeds in our fields and pastures are deemed to be bad. Over time man has caused disturbances to the system by plowing, raking, dozing, livestock grazing and in some cases the use of prescribed burns. From these human activities, weeds appear on the landscape. Most weed seeds are in the top inch of soil in pastures, yards, parks, roadsides, fence-lines, and other sites.
What do weeds tell us? Weeds present in pasture, fields, yards, etc. tell us that over time human management tied with drought and financial management decisions often lead to actions, which can build a weed environment.
So what is in the name “weed”? It turns out that no single plant in Texas has the name “weed”, but the term is used to classify what the eye of the beholder perceives. On any day and under any condition, any of the 5,000 species of plants known to occur in Texas, can get classified by humans as a weed. Generally, humans use the name “weed” when they do not know the correct name of the plant that they are looking at. The name of a weed is important because all knowledge known about a particular weed (its value and management) is tied to the plant’s name. By knowing the plant’s name, we can determine the management strategy to control this plant in the landscape.
Many weeds we deal with are herbaceous plants. Others are classified as forbs, grasses, sedges, and brushy weeds to name a few. Weeds may be annuals, living less than one year, or perennials that live for many years. Some germinate in the fall, over-winter in a rosette stage and go through stem elongation and flowering in the spring. This type of plant is considered to be a cool season annual. Warm season annual weeds will germinate from seed in the spring, go through stem elongation during the latter part of the spring and early summer, begin flowering in early to late summer, and then die by the fall or winter months. Biennial plants take two growing seasons to complete their life cycle. These factors are important when determining their value and management.
Annual weeds are easily controlled when they are young. Perennial weeds are typically controlled in the flowering or reproductive stage. Biennial plants are easily controlled in the rosette stage. For example, take woolly croton otherwise known as dove weed or goat weed. This is a summer annual that is easily controlled when the plant is young and before stem elongation occurs. On the other hand, blackberries or dewberries are perennial plants that are typically controlled in the flowering stage or early fruit stage. Bull thistle is a biennial weed that if controlled in the rosette stage before stem elongation takes place, control can be achieved successfully.
So as you can see, several factors help contribute to having weeds in our landscape. A Weed is a plant that is growing out of place or whose virtue has not yet been discovered. What is determined to be a weed to one person may be a desirable plant to another. The plant’s value to the landowner determines how it is managed.
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