07/01/2026
Our W**d of the month for July is Giant Hogweed, not to be confused with the native Cow parsnip.
ID 🕵️♀️
Giant Hogweed has a native lookalike, Cow Parsnip. Attention to detail is necessary to differentiate the two species. The most obvious sign is that Giant Hogweed is as its name says - very large! It can grow up to 12 feet tall, and has flowering umbels that can be over 1 foot wide, with leaves around 2 feet wide. The leaves are also deeply divided and almost spiky in shape. Stems will have blotchy, irregular dark red patterns, whereas Cow Parsnip has neatly lined dots. Giant Hogweed also blooms a full month after Cow Parsnip.
IMPACTS ‼️
Partly due to its often-gargantuan size, this species easily outcompetes native plants. It is toxic to wildlife, livestock, and humans. Giant Hogweed does have a deep taproot, but because it dies back over the winter, it provides very little erosion control. It often grows near waterways, where this impact is especially pronounced. This species can host some types of fungi that negatively impact a range of edible crops.
MANAGEMENT
Remove Giant Hogweed carefully. The sap from leaves and stems can cause chemical burns to the skin or eyes, so always take safety precautions. This species is not widely known in Oregon, so if you see it, report it at OregonInvasivesHotline.org right away. Replace Giant Hogweed with native species like Cow Parsnip, Pacific Rush, or shrubs like Red Osier Dogwood and Common Snowberry.
