Weed Control Service in Arizona — Phoenix Valley and Beyond

Johnsongrass, Crabgrass, Stinkgrass, Nutsedge Control

Johnsongrass ranks among the most aggressive weeds in the United States. It thrives in open, disturbed ground — particularly along irrigation ditches, streams, and moist waste areas throughout Arizona. Without consistent control, johnsongrass takes over agricultural land rapidly. It grows up to 8 feet tall with stems reaching 2.5 feet deep, produces more than 80,000 seeds per season, and flowers from April through November.

Large Crabgrass is a European native and the most widespread annual grassy weed in Arizona yards and landscaped areas. It favors moist soil and commonly appears in cultivated fields, roadsides, and lawns during summer. The plant grows 8 to 28 inches tall with many branches at the base, begins flowering in February, and matures from late May through October.

Stinkgrass appears throughout Arizona from early summer through late fall in cultivated crops, gardens, roadsides, and heavily soiled areas. It is less common in the northeastern part of the state. Researchers have found stinkgrass toxic to horses that consume large quantities over time. This European weed flowers from May through October and can contaminate crop seeding when mixed with small grains and seeds.

Yellow Nutsedge is one of the most common weeds in Arizona, flowering between May and the first fall frost. It spreads across cultivated fields, cotton fields, alfalfa pastures, dams, ditches, streams, and roadsides in large numbers.

Purple Nutsedge closely resembles yellow nutsedge but stays primarily confined to the valleys of southern Arizona. It flowers during the same window — May through fall frost. When purple nutsedge establishes itself in lawns, summer crops, ditch banks, and field borders, its stem, runners, and tubers make it extremely difficult to eliminate without professional treatment.

London Rocket, Milk Thistle, and Spiny Sowthistle

London Rocket is one of the first weeds to emerge in southern Arizona each winter, disappearing once temperatures rise. It grows predominantly in small grain fields, citrus orchards, roadsides, and gardens. London rocket is an extremely competitive winter weed, typically reaching 2 feet tall and flowering from December through May.

Milk Thistle originates from the Mediterranean region and appears most commonly in southern Arizona — particularly in the Salt River Valley. It features a stout stem with rigid branching and a reddish-purple flowering head. Milk thistle spreads along roadsides, irrigation ditches, and waste areas and has the potential to invade large areas of pastureland across Maricopa, Gila, Pinal, Pima, and Cochise counties. Once established, it forms thick clumps that crowd out desirable plants. It flowers primarily from April through June.

Spiny Sowthistle is a common European weed that grows abundantly in urban areas of the Arizona desert, particularly in the southern part of the state. Many people mistake it for a dandelion due to similar flowering buds. The key difference is its reddish, prickly stem that reaches up to 5 feet tall. Its growth rate depends heavily on winter and spring rainfall — the more rain Arizona receives, the more aggressively it spreads. Spiny sowthistle is a pest in winter vegetable crops, orchards, lawns, waste areas, and along stream banks.

Bermudagrass, Burroweed, and Climbing Milkweed

Bermudagrass is one of the most destructive plants in Arizona. Once it invades crops, fields, lawns, and gardens, it is nearly impossible to clear without professional treatment. Bermudagrass is also one of the leading causes of hay fever in the state. It serves as the most common summer lawn grass in southern Arizona but cannot tolerate freezing temperatures or shade. It flowers from mid-May through November.

Burroweed is a serious range pest that grows on dry desert roadsides, waste areas, mesas, grasslands, and slopes in eastern Arizona. Overgrazing and drought conditions allow it to spread rapidly. Animals generally avoid eating burroweed, but during severe droughts they may consume it — causing poisoning in livestock.

Climbing Milkweed thrives in arid areas and causes significant problems on ranches and residential properties. It climbs trees, fences, and ditches to spread through gardens and lawns. In Arizona, climbing milkweed appears throughout the southern and central regions in washes and arroyos. It flowers from April through October, with seedpods persisting through November.

Prostrate Knotweed, Puncturevine, Russian Thistle, and Tumble Pigweed

Prostrate Knotweed grows on dry, compacted soil in walkways, yards, and waste areas throughout Arizona. This annual weed produces many seeds and features small white flowers often hidden within the plant. It flowers primarily from March through October.

Puncturevine is one of the most abundant and problematic weeds in southern Arizona. It invades cotton fields, alfalfa pastures, roadsides, yards, citrus orchards, and walkways. After summer rains, puncturevine appears in large numbers, flowering from March through October with peak growth in July and August. The burs it produces scatter across the ground as they dry and can easily pierce shoes, bike tires, and bare feet.

Russian Thistle arrived in the United States in contaminated flax seed in the late 1800s and has since become one of the most common weeds in Arizona and other dry regions of the country. A single plant holds thousands of seeds that can remain viable for years. As the plant dries and matures, it breaks off at ground level and tumbles in the wind — scattering seeds across wide areas. Russian thistle flowers from May through November and grows in overgrazed grasslands, disturbed wastelands, and cropland throughout northeastern Arizona.

Tumble Pigweed spreads throughout Arizona in flax fields, cotton fields, cultivated areas, roadsides, river bottoms, rocky slopes, and open fields — essentially anywhere the wind carries its seeds. Like Russian thistle, it flowers from May through November, dries and turns prickly as it matures, breaks off at ground level, and disperses seeds as it tumbles in the wind.

Stop fighting a losing battle with Arizona’s most aggressive weeds. Atomic Pest Control’s dedicated Weed Division provides professional weed control across the Phoenix Valley and greater Arizona — with customized treatment plans, industry-leading products, and guaranteed results. Contact us today for a free estimate.