Giant hogweed is an herbaceous perennial or biennial flowering plant in the Apiaceae (carrot) family native to Asia. It is a very large plant reaching heights of 20 feet tall. It is a noxious weed in several states, a Federal Noxious Weed, and is a class A noxious weed in North Carolina and so far found only in Watauga County. The plant can take several years to flower but once it flowers and sets seeds it dies. However, thousands of seeds are formed. So far all sites found have been eradicated in NC. Read more at Giant Hogweed by the North Carolina Department of Agriculture. The rapid rate at which it grows means it can out compete native plants, especially along riparian corridors. Report any sightings of Giant Hogweed to the North Carolina Department of Agriculture or the NC Invasive Plant Council . The Plant Industry Division, under the NC Department of Agriculture and Consumer Services, prohibits the propagation, nursery cultivation, sale and/or distribution of Giant Hogweed. This plant prefers moist areas with some shade, particularly along stream banks, where it can lead to soil erosion and disperse seeds downstream. Cow parsnip is most often mistaken for giant hogweed and grows in NC. It is similar in appearance but a much smaller plant. Angelica, wild parsnip, Queen Anne's lace, and poison hemlock are also mistaken for this plant. Insects, Diseases, and Other Plant Problems: The sap of the plant is highly toxic and can cause sensitivity to UV rays causing severe blistering and burning from sun exposure. Removing this weed manually can therefore be quite dangerous and requires proper skin protection.
Curated pairwise relationships between this plant and others in the library — who feeds
whom, who competes, who confuses the pests. Green reads as a good pairing, red as one to avoid.
No curated interactions recorded for this species yet.
Also noted by NC State
Related species the NC State Plant Toolbox flags for this plant — look-alikes to tell
apart, and plants that play a similar role in a planting. Ones we carry in the library are linked.
Partial Shade (Direct sunlight only part of the day, 2-6 hours)
Soil texture
Clay; Loam (Silt); Sand
Soil drainage
Good Drainage | Moist
Growth rate
Rapid
Maintenance
High
Canopy layer
4 - Herbaceous
Form & Appearance
Habit / form
Erect
Leaf color
Green
Leaf type
Compound (Pinnately , Bipinnately, Palmately)
Leaf arrangement
Alternate
Leaf margin
Lobed
Leaf size
> 6 inches long, > 6 inches wide
Hairs present
No
Leaf detail
Very large green, up to 9 feet wide compound leaves with 3 deeply incised leaflets that are 3-5 feet wide. The leaflets near the top of the stem are less incised and not as large.
Flower color
White
Flower form
Umbel
Flower detail
Large white flat-topped umbel (carrot-like) inflorecences appear from June-July. They can reach 2.5' across.
Bloom time
Summer
Fruit color
Cream/Tan
Fruit type
Schizocarp
Fruit size
< 1 inch long, < 1 inch wide
Fruit detail
Ellpicial and dry, resembling small apples are .3" to .4" long and 1/4" wide. Seeds are cream-colored, flat with brown teardrop markings. Produced in August. with up to 1500 seeds
Stem color
Green
Stem detail
Hollow green stems with dark reddish-purple splotches and prominent coarse white hairs angled stems 2-4 inches in diameter.