Alligatorweed

Alternanthera philoxeroides

Alligatorweed is an invasive species of perennial broadleaf weed native to South America. Its ability to thrive in damp soil and grow on water makes it tough to control.

Identify

Opposite

Elliptical

Alligatorweed has unique characteristics that make broadleaf identification easy for this species. This non-native plant has sparse hairs on its leaf base and stem, along with white flowers that bloom in mid-summer. These paperish, ball-shaped flowers are located on short stems right at the leaf/stem joint. Alligatorweed stems differ between aquatic plants and land plants. When growing in water, the stems build up into large, interwoven mats. When growing in damp soil, this broadleaf weed sprouts underground stems that can grow over 3 feet long.

Life Cycle

Alligatorweed is mostly found in the southern parts of the United States but also travels as far north as Illinois. It especially likes to infest waterways. This perennial broadleaf weed can sprout new weeds by both seeds and creeping roots—even a tiny piece of a stem can be enough to keep the weed life cycle going.

Control

Unlike some other types of broadleaf weeds, Alternanthera philoxeroides is very difficult to control through proper mowing, watering or even physical removal. That’s because this weed can spread from seeds, stem fragments or roots. Quick control is crucial with Alligatorweed, as it poses enormous threats to your grass and landscaping. The root’s thick matting can restrict oxygen levels of water and interfere with irrigation in your lawn. TruGreen® uses a selective systemic broadleaf weed killer to fight Alligatorweed in your lawn. This ensures that the control product moves throughout the entire weed, controlling it completely, root and all.