One-seed hawthorne

Genus: Crataegus

Species: monogyna

Description: Single-seed hawthorn is a deciduous shrub or small tree to 20 feet (6m) tall, with clusters of white flowers in mid-spring, small red berries in autumn, lasting to late winter.

Where it grows: A common invasive species in prairies and deciduous woodlands in the Willamette Valley, Oregon, where it has been present for over 100 years. Grows best in humid or subhumid temperate regions and does well on most soil types, riparian areas, abandoned fields and pastures, oak woodlands, and other forested habitats.

How it spreads: Fruit-eating birds are the primary agents of seed dispersal, seeds also spread by clinging to farm machinery, vehicles, and animals or by fruit-eating mammals.

What it threatens: Single-seed hawthorn displaces native plants, and dense thickets alter the structure of the forest understory and make movement of large animals difficult.

More information: Nature Conservancy website

Disclaimer - Clean Water Services does not endorse or recommend specific herbicides for use in controlling these species. To protect water quality, always follow herbicide label directions and obey application laws when using any herbicide.