Lamb’s Quarters

Melon (cantaloupe, honeydew), banana, peach

Lamb’s Quarters ( _Chenopodium album_) is one of the most widespread annual weeds in the world, found across North America, Europe, the Middle East, Australia, and beyond. In Arizona, it thrives in disturbed soils statewide, from the desert valleys of Maricopa, Pinal, and Mohave counties to the elevated grasslands and juniper-pine forests of Coconino, Navajo, Apache, and Yavapai counties — growing at elevations from sea level up to 9,500 feet.

A fast-growing, wind-pollinated weed, Lamb’s Quarters poses a meaningful allergy burden in Arizona from summer through fall. Its small airborne pollen grains are released between June and October, with peak concentrations in August and September when other weeds like pigweed and ragweed are also at their most active. This overlap makes the late-summer and early-fall months particularly difficult for allergy sufferers across the Phoenix metro, Tucson area, Flagstaff, and the Colorado Plateau communities.

The plant commonly colonizes roadsides, vacant lots, construction sites, agricultural fields, overgrazed rangelands, and residential gardens throughout Arizona, essentially any disturbed soil where it can take hold. It is not considered drought-adapted in the same way as native Sonoran Desert plants, but it is opportunistic enough to establish wherever moisture is intermittently available, making it a recurring presence in irrigated landscapes, drainage channels, and the edges of cultivated areas.

From a landscaping perspective, Lamb’s Quarters is not recommended for intentional planting in Arizona. It is a prolific seed producer and its classification as a noxious weed in several states reflects its aggressive spread. Gardeners and homeowners should remove plants before they flower to limit pollen production and reduce the local seed bank.