Also known as: goat’s head, bullhead, Texas sandbur, calthrop, devil’s thorn, tackweed
Puncturevine is aptly named! This plant has spiny seed heads that can puncture bicycle tires, inflatable rafts, animal paws, and even shoes! Be on the lookout as it is starting to pop up in Washington County.
Description:
| Life Cycle: | Annual (life cycle lasts one year) |
| Early Detection and Rapid Response species: | Yes |
| Height: | Lays flat on the ground up to 6 feet (2 meters) across. |
| Stem & Leaf Description: | It grows many trailing, hairy stems from a central taproot. Leaves grow opposite along the stem and have several pairs of hairy leaflets. |
| Fruit & Flower Description: | Small yellow flowers have five petals that open in the morning and close in the afternoon. The fruit, also known as a bur, has sharp, rigid spines, which some say resemble a goat’s head. |
| Bloom Time: | April to October |
Habitat:
- Puncturevine is commonly found in pastures, along roads, beaches (both ocean and river), and parks.
- It is especially troublesome when growing in yards or sports fields where it goes unnoticed until a bur is stepped on.
- It is drought tolerant and grows in most soil types but prefers sunny areas with dry, sandy soils.
Impact:
- Puncturevine is toxic to livestock, particularly sheep and cattle. When livestock consume it in large amounts, it can cause blindness, paralysis, and even death.
- Sharp spines on its burrs allow its seeds to be easily transported by clothing, animal’s fur, and car or bike tires
- Its burs are painful to step on and can easily puncture bicycle tires or footwear.
What we’re doing about it:
- Puncturevine is a priority species for the Tualatin SWCD. As such, our Invasive Species Program has been actively monitoring and treating it throughout the watershed.
- If identified within Washington County, a specially trained crew can come out survey for puncturevine. If found, the crew will treat the infestation for free.
What you can do about it:
- If you think you’ve found puncturevine in Washington County, please report it to the Oregon Invasive Species Hotline.
- Wear gloves whenever handling puncturevine to avoid being poked by its sharp burrs.
- Hand pulling or tilling the soil (1 inch or less) is effective in March before plants have begun to produce seeds. After removing puncturevine, throw it away in a plastic bag in the trash—not your yard waste bin or home compost.
Noxious Weed Listing:
| State of Oregon: | Class B |
| State of Washington: | Class B |
More Resources:
Download the Puncturevine Best Management Practices Factsheet
- Pacific Northwest Weed Management Handbook: Puncturevine
- University of California, Weed Research and Information Center: Puncturevine