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Heracleum mantegazzianum is often confused with:
Conium maculatum White flower clusters.
Plants that fill a similar niche:
Lonicera japonica Lonicera japonica flowers
Sorghum halepense Form - Summer - Warren Co., NC
Wisteria sinensis Flowers

Heracleum mantegazzianum

This plant has high severity poison characteristics.
See below
This plant is an invasive species in North Carolina
Description

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:
Tags:
#invasive#poisonous#weedy#large leaves#high maintenance#fast growing#aggressive#large flowers#Noxious Weed List#perennial weeds#skin irritation#federal noxious weed list#large plant
 
Cultivars / Varieties:
Tags:
#invasive#poisonous#weedy#large leaves#high maintenance#fast growing#aggressive#large flowers#Noxious Weed List#perennial weeds#skin irritation#federal noxious weed list#large plant
  • Attributes:
    Genus:
    Heracleum
    Species:
    mantegazzianum
    Family:
    Apiaceae
    Life Cycle:
    Biennial
    Perennial
    Country Or Region Of Origin:
    Asia
  • Whole Plant Traits:
    Plant Type:
    Herbaceous Perennial
    Perennial
    Weed
    Habit/Form:
    Erect
    Growth Rate:
    Rapid
    Maintenance:
    High
  • 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
  • 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
  • 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.
  • 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.
  • 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.
  • Landscape:
    Problems:
    Contact Dermatitis
    Invasive Species
    Poisonous to Humans
    Weedy
  • Poisonous to Humans:
    Poison Severity:
    High
    Poison Symptoms:
    Sap from the plant causes senstiviety to UV rays which results in severe burns and blistering of the skin.
    Poison Toxic Principle:
    Furanocoumarins
    Causes Contact Dermatitis:
    Yes
    Poison Part:
    Sap/Juice