BugwoodWiki Article

giant hogweed
Heracleum mantegazzianum Sommier & Levier

Overview

Appearance
Heracleum mantegazzianum is a herbaceous biennial or monocarpic perennial that can grow up to 15-20 ft. (4.3-5.8 m) in height. The stem is hollow and usually blotched with purple. Both the leaf stalks and stem produce pustulate bristles. The stem can be 2-4 in. (4.8-9.6 cm) in diameter.
Foliage
The leaves are ternate or ternate-pinnate with pinnately lobed lateral segments. They can be up to 9.8 ft. (3 m) in breadth.
Flowers
Heracleum mantegazzianum flowers from June-July. The inflorescence has many white florets (with petals about 0.4 in. [1 cm]) that form a flat-topped umbel. Each inflorescence can have a diameter of up to 2.5 ft. (0.72 m).
Fruit
The fruits are dry and elliptic, measuring 0.3-0.4 in. (8-11 mm) long and 0.25-0.3 in. (6-8 mm) wide. The fruits have brown resin canals that can be up to 0.04 in. (1 mm) in diameter.
Ecological Threat
Heracleum mantegazzianum can outcompete species for habitat, especially in riparian zones, and it may cause increased soil erosion. This plant is on the federal noxious weed list because of its poisonous sap. This sap makes skin very sensitive to UV radiation, causing blistering and severe burns. Caution should be taken when handling this weed. Removing it manually becomes very difficult because of the danger caused by its sap.

Resources

Selected Images


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giant hogweed
Heracleum mantegazzianum
Fruit(s)
Jan Samanek
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giant hogweed
Heracleum mantegazzianum
Flower(s)
Thomas B. Denholm
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giant hogweed
Heracleum mantegazzianum
Flower(s)
Terry English
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Heracleum mantegazzianum
Foliage
Donna R. Ellis
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giant hogweed
Heracleum mantegazzianum
Infestation
USDA APHIS PPQ Archive
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Heracleum mantegazzianum
Infestation
Jan Samanek
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Heracleum mantegazzianum
Control
Terry English
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giant hogweed
Heracleum mantegazzianum
Plant(s)
Randy Westbrooks
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giant hogweed
Heracleum mantegazzianum
Foliage
Jan Samanek
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giant hogweed
Heracleum mantegazzianum
Stem(s)
Leslie J. Mehrhoff
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giant hogweed
Heracleum mantegazzianum
Feature(s)
Leslie J. Mehrhoff
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giant hogweed
Heracleum mantegazzianum
Fruit(s)
Leslie J. Mehrhoff
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giant hogweed
Heracleum mantegazzianum
Flower(s)
USDA APHIS PPQ Archive
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giant hogweed
Heracleum mantegazzianum
Infestation
Barbara Tokarska-Guzik
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Heracleum mantegazzianum
Seed(s)
USDA APHIS PPQ Archive
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Heracleum mantegazzianum
Seed(s)
Cesar Calderon
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giant hogweed
Heracleum mantegazzianum
Plant(s)
Randy Westbrooks
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giant hogweed
Heracleum mantegazzianum
Plant(s)
Thomas B. Denholm
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giant hogweed
Heracleum mantegazzianum
Control
Thomas B. Denholm
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giant hogweed
Heracleum mantegazzianum
Damage
USDA APHIS PPQ Archive

Maps


EDDMapS Distribution - This map is incomplete and is based only on current site and county level reports made by experts, herbaria, and literature. For more information, visit www.eddmaps.org

EDDMapS Distribution

State Regulated List - This map identifies those states that list this species on their regulated list. For more information, visit Invasive.org

State Regulated List

Taxonomic Rank

Kingdom: Plantae
Phylum: Magnoliophyta
Class: Magnoliopsida
Subclass: Rosidae
Order: Apiales
Family: Apiaceae
Genus: Heracleum

Other System Links

Plants: HEMA17
Bayer: HERMZ
GRIN: 18896
ITIS: 502954
NPDN Pest: PFFAQBC

Categories

Category: Forbs/Herbs