Giant Cow Parsley Heracleum mantegazzianum
Other Common Name(s):
- Phonetic Spelling
- heh-RAK-lee-um man-teh-GAZ-zee-ay-num
- This plant has high severity poison characteristics.
- See below
- Description
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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 https://caldwell.ces.ncsu.edu/wp-content/uploads/2018/06/Giant-Hogweed-Pest-Alert.pdf?fwd=no. The rapid rate at which is grows means it can outcompete native plants, especially along riparian corridors.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.
- See this plant in the following landscape:
- Cultivars / Varieties:
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- Tags:
- Cultivars / Varieties:
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- Tags:
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Attributes:
- Genus:
- Heracleum
- Species:
- mantegazzianum
- Family:
- Apiaceae
- Life Cycle:
- Biennial
- Perennial
- Country Or Region Of Origin:
- Asia
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Whole Plant Traits:
- Plant Type:
- Herbaceous Perennial
- Perennial
- Poisonous
- Weed
- Habit/Form:
- Erect
- Growth Rate:
- Rapid
- Maintenance:
- High
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Cultural Conditions:
- Light:
- Partial Shade (Direct sunlight only part of the day, 2-6 hours)
- Soil Texture:
- Clay
- Loam (Silt)
- Sand
- Soil Drainage:
- Good Drainage
- Moist
- USDA Plant Hardiness Zone:
- 3a, 3b, 4a, 4b, 5a, 5b, 6a, 6b, 7a, 7b, 8a, 8b, 9a, 9b
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Fruit:
- Fruit Color:
- Cream/Tan
- Display/Harvest Time:
- Fall
- Fruit Type:
- Schizocarp
- Fruit Length:
- < 1 inch
- Fruit Width:
- < 1 inch
- Fruit Description:
- 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
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Flowers:
- Flower Color:
- White
- Flower Inflorescence:
- Umbel
- Flower Bloom Time:
- Summer
- Flower Description:
- Large white flat-topped umbel (carrot-like) inflorecences appear from June-July. They can reach 2.5' across.
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Leaves:
- Leaf Color:
- Green
- Leaf Type:
- Compound (Pinnately , Bipinnately, Palmately)
- Leaf Arrangement:
- Alternate
- Leaf Margin:
- Lobed
- Hairs Present:
- No
- Leaf Length:
- > 6 inches
- Leaf Width:
- > 6 inches
- Leaf Description:
- 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.
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Stem:
- Stem Color:
- Green
- Stem Is Aromatic:
- No
- Stem Cross Section:
- Angular
- Stem Form:
- Straight
- Stem Surface:
- Hairy (pubescent)
- Stem Description:
- Hollow green stems with dark reddish-purple splotches and prominent coarse white hairs angled stems 2-4 inches in diameter.
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Landscape:
- Problems:
- Contact Dermatitis
- Poisonous to Humans
- Weedy
