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Singleseed hawthorn flowers. Photo Credit: Robert Vidéki, Doronicum Kft., Bugwood.org -
Singleseed hawthorn shrubs. Robert Vidéki, Doronicum Kft., Bugwood.org -
Also known as: English hawthorn, common hawthorn, oneseed hawthorn, Mayblossom
Like invasive blackberry, singleseed hawthorn is an all-too-common weed that is a thorn in landowners and land managers’ side! Commonly growing in vacant lots, forest understories, and along roadsides, this plant has sharp thorns that can pierce leather gloves! Even worse, this plant threatens endangered Oregon oak woodlands by outcompeting young seedlings.
Description:
| Life Cycle: | Perennial (life cycle lasts more than one year) |
| Early Detection and Rapid Response species: | No |
| Height: | Can grow up to 45 feet (14 meters), but more commonly between 6.5 – 20 feet (2 – 6 meters) tall. |
| Leaf Description: | Dark green leaves are alternatively arranged with deep lobes. Its branches are smooth with pale grey bark and have many stout thorns. |
| Fruit & Flower Description: | The flowers grow in clusters of five to twenty five and are white. Each flower has five petals. The plant also produces egg-shaped, dark-red berries that contain a single seed. |
| Bloom Time: | May to early June |
Habitat:
- Singleseed hawthorn thrives in a wide variety of habitats including forest understories and meadows.
- It prefers moist soils, but established plants can survive in moderate drought conditions.
Impact:
- Singleseed hawthorn is especially problematic in oak woodlands, where it outcompetes native Oregon white oak (Quercus garryana).
- It can also hybridize with native Douglas hawthorn (Crataegus douglasii), creating a weedier, more competitive hybrid species.
- It grows in thorny thickets that make it difficult for animals to access to water and food.
What you can do about it:
- Pulling or digging up small hawthorn trees or shrubs is easiest in the fall through spring when the ground is damp. Make sure to monitor the area for several years and pull any re-sprouting plants.
- Weed wrenches can assist with removing hawthorn. If you are in Washington County, we lend these tools for free from our Tool Loan Program.
Look-alikes:
The native Douglas hawthorn looks similar to singleseed hawthorn. Douglas hawthorn has stout thorns, like singleseed hawthorn, but its leaves are weakly lobed and its fruits are dark purple, rather than dark red.
Noxious Weed Listing:
| State of Oregon: | Class B |
| State of Washington: | Class C |
More Resources:
Download the Singleseed Hawthorn Best Management Practices Factsheet
- Pacific Northwest Weed Management Handbook: English hawthorn
- University of California, Weed Research & Information Center: English hawthorn