Types of Weeds in Phoenix

We offer weed control services to the entire Phoenix valley and surrounding areas.

Common Names: Crabgrass, Large

Other Names: Hairy crabgrass, crabgrass, summer grass

Origin: Native to Europe and now widespread in the United States.

Biology: A summer annual grass weed, found in virtually any situation – row crops, orchards, pastures, roadsides, landscape, turf. Seeds germinate from very early spring throughout the summer months, and plants mature from late spring through the summer into early fall. Lower joints of the stems also tend to extend roots where they touch the ground, and the plants will spread laterally in this manner.

Identification: One of two principal species of crabgrass, Large Crabgrass may be distinguished from Smooth Crabgrass by its larger, hairy leaves. Mature plants may be prostrate or upright, depending on the growing condition. In regularly mowed turf they adapt with lower stems. Stems may be as long as 28 inches, and are branched at the base. Stems tend to be thin and weak. Leaves are light green and up to about 7 inches long. The edges of the leaf blades are covered with fairly long hairs. The flower head is arranged umbrella-like, consisting of from 3 to 11 slender branches that may be up to 4 inches long. The branches arise from separate but very close points at the end of the stem, or a few may arise from the same point. Flowers are arranged on one side of each branch.

Characteristics Important in Control: Germination once soil temperatures have risen sufficiently. In the west generally this is by the first of March.

Common Name: Desert willow

Origin: Native to the southwest states of the United States and into Mexico. It is found from Texas north to Kansas and west to California in the more arid regions.

Biology: A perennial shrub to a bushy tree that reproduces from seeds. This is primarily an arid-lands or desert plant that is highly tolerant of dry, sandy soils. It may grow along roadsides where its thick foliage can obscure visibility.

Identification: A dense shrub with multiple, branching woody stems, and growth to as high as 25 feet. Leaves are elongate and narrow, and up to 6 inches long, and will fall from the plant in the winter. Flowers occur on elongated stems at the ends of the branches, with several to two dozen flowers alternating along the stem. The flower is pink, white, or lavender, with a long basal tube and irregular shaped petals.

Characteristics Important in Control: Control generally is not needed for this native plant. When it is growing in an undesirable location it can be physically removed.

Common Name: Saltcedar

Other Names: Tamarisk, tamarik

Origin: Native to Eurasia and introduced to the United States as an ornamental plant. Now found widespread in the U.S.

Biology: A perennial, evergreen shrub or small tree whose leaves are small and very reminiscent of cedar branches. Commonly found in streambeds or along canals and reservoirs, and their growth can be so intense that they choke out other forms of vegetation, offering little plant diversity for wildlife. Their intake of water is so high that they can actually deplete the available water in ponds or streams.

Identification: Mature plants can grow as high as 20 feet, and they are multi-branched and extensively spreading. The bark on the stems is reddish brown. Leaves are small and scale-like, giving the foliage almost the look of a conifer such as cedar. Flowers are pink to white and are very small, but grow in showy clusters of many dozens of flowers on finger-like branches at the ends of the stems.

Characteristics Important in Control: This is a perennial with an extensive root system, and physical removal would be difficult.

Common Name: Red sorrel

Other Names: Sheep sorrel, sour grass, Indian cane, field sorrel, horse sorrel, sour weed, red-top sorrel, cow sorrel, red weed, mountain sorrel.
Origin: Native to Europe, now distributed widely across the United States and southern Canada.

Biology: A perennial broadleaf plant, with slender, creeping rhizome rootstocks. Foliage usually stays green throughout the year, with some yellowing in the fall possible. Reproduction is from seeds and from the rhizomes, with rhizomes forming new buds in early spring to produce new basal rosettes of leaves.

Identification: Mature plants generally are low but may grow to 2 feet tall, with somewhat woody stems at the base. Underground structures include a yellow taproot and numerous slender rhizomes. Mature leaves are widely arrow shaped, with 2 wide lobes at the base and a long stem. Leaves form as a rosette from a common base. Flowers are produced throughout the summer on long, thin stems, as clusters of tiny yellow (male) or reddish (female) flowers on separate plants. Flower stems are numerous and heavily branched.

Characteristics Important in Control: A problem weed in landscape, turf, roadsides, and agricultural crops. It thrives best on acidic soil, and in soils low in nitrogen. Physical removal is difficult, as rhizomes break loose and will grow additional plants. Poorly drained soils also may encourage its growth.

Common Name: Russian thistle

Other Names: Tumbleweed, common saltwort, saltwort, Russian tumbleweed, tumbling weed, windwitch, witchweed

Origin: Native to Eurasia, but introduced to the United States from Russia in sacks of flaxseed, that spilled along railways as it was transported, spreading the weed throughout the western U.S.

Biology: An annual broadleaf weed that grows particularly well in drier climates, but capable of infesting virtually any agricultural, landscape, or roadside situation. It also serves as a host of the sugarbeet leafhopper, which transmits curly to virus to vegetable crops. Seeds germinate from late winter into early summer, and the plants mature in late summer into the fall. Each plant produces enormous numbers of seeds, and due to its rolling movement in strong winds it may disperse these over great distances.

Identification: Mature plant is very bushy and wide, and up to 5 feet tall. Branches are numerous, stiff and thin, and nearly hairless. Young plants are smoky dark green, and when mature the plant is gray to grayish brown. Once it dies the shallow root breaks away to release the plant in the wind. Leaves are extremely thin, almost resembling pine needles up to 3 inches long. As the plant matures the tips of these leaves become spiny, giving it the misnomer of “thistle”. Flowers are tiny and inconspicuous, growing in clusters at the base of the leaves.

Characteristics Important in Control: Heavy seed production makes pre-emergent control more difficult. Mature plants become stiff and leathery and do not disintegrate easily in the winter, creating piles of dead plants to deal with if they are allowed to grow to maturity.

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