What is it?
This Asian native first became popular in the southern United States, where it was planted on people’s porches. It now is known commonly as the vine that ate the south. Kudzu is a perennial, trailing vine that can grow up to 1 foot a day and as long as 98 feet. A single root crown may produce as many as 30 vines, which become hairy and woody and expand out in all directions.
Is it here yet?
No. Kudzu was discovered in Clark County, but was treated and removed. There are no other known infestations, but it has been found in Oregon and poses a great risk to Washington.
Why should I care?
Kudzu is a highly aggressive, invasive plant that is extremely difficult to control once established. Kudzu is so aggressive it covers and smothers all other plants in its path resulting in solid stands that eliminate native species. Kudzu may cover trees, killing them by blocking out light for photosynthesis, or damaging tree limbs with the weight of the vines. Once established, kudzu can render lands unusable for growing trees or agriculture. The weight of the vines can bring down power lines and collapse buildings.
What should I do if I find one?
How can we stop it?
- Do not purchase, plant, or trade this species.
- The Washington State Noxious Weed Control Board has listed kudzu as a Class A noxious weed since 2003. County weed coordinators are on the lookout for this species. State law requires that all Class A weeds be eradicated.
What are its characteristics?
- Dense stands of kudzu are characterized by thousands of single-colored plants covering everything in their range.
- Kudzu leaves are alternate and compound with three oval- to nearly heart-shaped leaflets reaching 3 to 4 inches in length.
- Leaves are dark green and may be entire or slightly lobed.
- Leaves and stems are hairy.
- Kudzu flowers are purple or purplish-red with flower clusters that reach up to one foot long.
- Each floret is pea-like, ½ to ¾ inches long.
- The flowers are fragrant and described as grape-like.
Where can I get more information?
- Washington State Noxious Weed Control Board
- King County
- U.S. Department of Agriculture
- See more photos at the University of California - Berkeley