A weed is a plant. There is no special biological taxonomic category for "a weed", just as there is no special taxonomic category for tree or bush. Each of these groupings is just an artificial classification that we have invented to help us describe plants that share certain characteristics.
Trees are tall and woody with branches at the top. Bushes are more branched than are trees. Weeds are merely herbaceous plants that have features that enable them to survive our attempts to eradicate them. And it is much easier to control lawn weeds when you can identify them and understand their growing strategies.
Common Lawn Weeds
Some of the plants that consistently foil our efforts to create a soft green carpet of monoculture include:
- Yellow Wood Sorrel (Oxalis stricta); the petite ground hugger with delicate yellow flowers and leaves that look a little like shamrocks
- Plantain (Plantago spp.); the prostrate whorl of leaves topped by a tough shoot that bares an unremarkable inflorescence
- Hawkweed (Hieracium spp.); the close relative of dandelion
- Dandelion (Taraxacum spp.); with its low-growing leaves, fluffy yellow flower and parachuted achenes
Characteristics of Plants that are Weedy
Weed Seeds
The seeds of weeds tend to be produced in large numbers and germinate (sprout) very quickly. Many weedy plants have wind-blown seeds, which help them to widely disperse.
Plant Growth Form
All of the weedy plants listed above have flattened leaves that hug the ground. Even if a hungry herbivore munches on the flowers, or the blades of a lawn mover whack them off, the main body of the plant is so low that it usually remains intact and able to generate new stalks and flowers.
Plant Life Cycle & Hardiness
Both of these factors impact how quickly a plant will populate. Just like the seeds of these species germinate quickly, the new seedlings grow into mature plants very quickly as well. If you are a gardener who starts plants from seed, think about how long it takes for a green pepper plant to germinate and grow large enough to produce mature peppers with the next generation of seeds. This process requires at least 3 months, under the best of conditions. And peppers are picky; green pepper germination and growth requires warm weather and evenly moist soil.
Compare that to the 8 weeks it takes a dandelion seed to develop into a flowering mature dandelion puff with its own little seed parachutes. And dandelions are not fickle about their growing conditions; cold weather, hot weather, no problem. Dry periods with little rainfall are not an issue either; the dandelion has a very long tap root that enables it to drink deep.
Roots of Weeds
In fact, all of the weedy plants named above share the vital characteristic of having tap roots. A tap root is a long, single root. In addition to being able to draw water from deep in the ground, tap roots store a great deal of energy. Even if a frustrated gardener pulls the majority of the weed out of the ground, any taproot that is left can generate a new plant.
More Information
If you’d like to control the weeds in your lawn organically, see the GardensAlive! website. To learn more about gardening in general you can turn to additional Suite101 articles, such as Grow an Easy Vegetable Garden, and Container Kitchen Herb Garden.
Tami Port - Tami Port is a college professor of cell and microbiology and creator of ScienceProfOnline.com, a free science education website.
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