Sunflower broomrape
Orobanche cumana
Family: Orobanaceae
Other Scientific Names:
Orobanche ceruna subsp. Cumana
Weed class: A
Year Listed: 2026
Native to: Eurasia
Is this Weed Toxic?:
Not known to be
Legal listings:
Why Is It a Noxious Weed?
Sunflower broomrape can reduce sunflower and tomato yield by 80% to 100%. It also heavily impacts tobacco, potatoes, peppers, sage, and potentially our native sunflowers.
How would I identify it?
General Description
Sunflower broomrape is only visible above the soil when it is going to flower soon, is flowering, or is seeding. This process can take only a couple weeks in June and July.
Before flowering, it can look like a ghostly, pale, fuzzy asparagus.
It can reach up to 2 feet in height, but is usually shorter.
Flower Description
Flowers are curving trumpet-shaped tubes. They are fuzzy and can be purple, white, tan, or brown, generally with a yellowish center when fully open.
Leaf description
As an obligate parasite, which does not photosynthesize, it does not have true leaves. There are small, triangular bracts that appear on the stem and near the flowers, but are not leaves.
Stem description
Stems are upright and unbranching. Before and during flowering, they are fuzzy, and tan to brown to white, perhaps with some purple tint.
After flowering, the stems become thin, firm, and dark brown, with small pods with the dust sized seed inside.
Fruit Seed Description
The seeds are produced prolifically, are dust sized, can easily spread on the wind, and can remain viable in the soil for at least 50 years, but likely longer.
The seeds are stored in small hard, brown pods or capsules, which open at the top and look like very tiny tulips when opened.
May Be Confused With
Hellroot, Orobanche minor, is another non-native broomrape. It is only known in Western Washington currently, where it is found in open grassy, and often disturbed sites. It looks very similar to sunflower broomrape, so make sure to send photos and samples to WSDA and your local county weed board if you are concerned!
Suksdorf’s broomrape (Aphyllon ludovicianum) and Pine broomrape (A. pinorum) are two native holoparasite plants that are covered in fuzzy hairs like sunflower broomrape, and have white, purple, or tan stems and flowers. Pine broomrape only parasitizes off of ocean spray (Holodiscus discolor) in Washington and thus is primarily found forest understories. Suksdorf’s broomrape parasitizes on woody plants in the Asteraceae family, including sages (Artemisia) just like sunflower broomrape. However, the centers of Suksdorf’s broomrape flowers are very obviously yellow and the entire plant looks much bristlier and more robust than sunflower broomrape.
Where does it grow?
Agriculture lands, flower fields, sagebrush steppe, pasture, grasslands, open areas, and among sunflower, tomato, tobacco, potato, and pepper crops.
How Does it Reproduce?
Seed only.
How Do I Control It?
It is very important if you think you have found sunflower broomrape to contact WSDA and your local county weed board as soon as possible! Don't control it on your own, special techniques need to be taken to ensure all seeds and plant parts are fully destroyed to stop this plant from taking ahold in North America.
For More Information
Our draft written findings on sunflower broomrape.
WSDA's page on sunflower broomrape.
Additional Photos
