Weed Identification & Control

The first step to weed control is identifying the weed.

Weeds are a nemesis to every gardener. Dandelions are one of the most well-known offenders, but numerous others take root. These weeds often go unidentified, making weed control almost impossible. Most weeds are classified into four groups, consisting of broadleaf weeds, sedge, grasses and aquatic weeds. Knowing how to identify and control these weeds will help make gardening less tiring and more enjoyable.

Broadleaf Weeds

As their name implies, broadleaf weeds have a wide leaves that come in a variety of shapes and arrangements. The edges may be smooth or pointed, while some have a serrated appearance. Broadleaf weeds can grow vertically, varying in height, or they can spread out, growing quite close to the ground. Some species have flowers, such as white clover, which is frequently found in lawns. Other types of broadleaf weeds include lambsquarters and prickly lettuce.

Grass

Weeds classified as grasses have long, thin leaves, and the stems are usually hollow. The root systems for many species spread out just below the dirt's surface with new plants sprouting from these roots. The easiest way to identify certain plants is by the appearance of the flowers. Some grassy weeds include foxtail, crabgrass and wild oats.

Sedge

Sedge weeds are often mistaken for grasses, though distinct characteristics set the two apart. Stems on sedges are triangular in shape, whereas grasses are round and hollow. Most species of sedge have long leaves, typically appearing in groups of three. The most particular difference is in the root systems. Sedges can spread above ground, starting new plants from stolons that spread out from the base of the sedge. Other species of sedge have underground tubers from which a sedge species can start numerous new plants. As well, root systems can spread out a distance from the plant and start new plant growth. Types of sedge include blunt spikerush and nutsedge.

Aquatic Weeds

Aquatic weeds spend some portion of their life in a water environment. When growing in water, these plants are easily identified. However, some species, such as blunt spikerush, grow on land as well and are classified in both sedge and aquatic weed groups. Cattails are one of the most well-known aquatic weeds.

Control

One of the most important elements to weed control is not allowing the weed to go to seed. Hand-pull the weed or cut off the top if necessary. When preparing soil, don't dig too deep since some weeds can remain dormant until brought to the surface. Consider using mulch made from bark or straw in flowerbeds to keep weeds from feeding off the sunlight. Also, plant groundcover in bare patches to help with weed control. Herbicides may be used as well, but keep in mind that herbicides kill some desirable plants, and you may have to wait a period of time before planting in a sprayed area.

References

• University of California, Integrated Pest Management Program: Identification-Weed Photo Gallery
• University of Nevada, Cooperative Extension: Weed Identification and Control Guide
• University of Illinois Extension, Homeowner's Column: Weed Identification and Control

Resources

• Weed Science at the University of Illinois: Weed Identification
• Weed Science Society of America: Weed Identification