Can I grow this in my garden?

It is strongly discouraged due to its invasive nature and extreme health risks to humans and pets.

How do I get rid of it?

Professional removal is recommended, as any contact with the sap can cause severe burns.

Plant guide

Giant Hogweed.

Heracleum mantegazzianum

Pronounced heh-RAK-lee-um man-teh-gaz-ee-AH-num

Also known as Giant Hogweed, Mantegazzi's Cow-Parsnip

This massive biennial plant is known for its impressive height and striking white flower clusters. It is considered a highly invasive species in many regions. Please be extremely cautious, as its sap causes severe skin irritation when exposed to sunlight.

At a glance

Care level: Easy
Plant type: Herbaceous biennial
Light: Full sun to partial shade
Indoor light: Direct sun
Water: Every 3 to 7 days
Mature size: 15 feet
Growth rate: Fast
Hardiness: USDA 3 to 8
Bloom time: Early to mid summer

Care

This plant thrives in moist, disturbed soil and spreads rapidly through seed dispersal. You should monitor for unwanted seedlings to prevent it from taking over your garden. Always wear protective clothing and eye gear if you must handle this plant to avoid contact with the dangerous sap.

Watering: Keep the soil consistently moist but not waterlogged.
Feeding: Apply a balanced fertilizer during the active growing season.
Pruning: Remove flower heads before they set seed to control spread.
Repotting: Repot only if the plant is being grown in a container, though it is rarely recommended.
Soil: Moist, nutrient rich soil
Soil pH: 6.0 to 8.0
Temperature: -25 to 30°C
Humidity: 40 to 80%
Drought tolerance: Moderate
Lifespan: Monocarpic perennial, typically lives 3 to 5 years before flowering and dying.
Deer and rabbits: High

Safety

People: All parts of the plant are toxic, and the sap is a severe skin irritant that causes blistering upon sun exposure.
Pets: The sap is toxic to both cats and dogs, causing severe blistering and skin inflammation upon contact.
Children: This plant is extremely dangerous to children due to its toxic sap and potential for causing severe, permanent skin damage.
Contact allergens: The sap is a potent photosensitizing agent that causes severe skin inflammation and blistering when exposed to UV light.
Airborne allergens: The pollen can cause mild respiratory irritation in sensitive individuals.
Edibility: This plant is highly toxic and should never be ingested.

How to identify it

Reaches heights up to 15 feet
Large, deeply lobed compound leaves
Purple blotches on thick stems
Huge umbrella shaped white flower heads
Coarse white hairs on stems

Height: 2 to 5m
Spread: 1 to 2m
Leaves: bright green, deciduous
Flowers: white, 50 to 80cm
Fruit: brown, late summer

Problems to watch for

Powdery mildew · A fungal infection that creates a white powdery coating on the leaves.

By symptom

Plant problems by symptom

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Growing it

Propagation: seed
When to plant: spring, autumn
Overwintering: The plant dies back to the ground in winter, leaving only the root system to survive until spring.
In containers: It is not suitable for containers due to its massive size and deep taproot.

Because this plant is highly invasive and dangerous, it is best not to include it in any garden guild.

Grows well with

Common Nettle · They often share the same disturbed, nitrogen rich habitats.

Similar species

Cow Parsnip · It is a much smaller, native North American relative that lacks the extreme toxicity of the giant species.

Science

Family: Apiaceae
Genus: Heracleum
Order: Apiales
Class: Magnoliopsida
Native range: Caucasus region of Eurasia
Conservation: It is widely classified as an invasive species and a noxious weed in many regions, often subject to mandatory control programs.

It thrives in disturbed areas, riverbanks, and roadsides where it outcompetes native vegetation through rapid growth and dense shade.

Value to wildlife: nectar source
Pollinators: bees, beetles, butterflies
Uses: historically grown as an ornamental; now restricted or banned in many regions, botanical interest

Through the year

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Flowering

Fruiting

Foliage

Ecological indicators

Salinity: 2/9
Soil reaction: 6/9
Light: 7/9
Temperature: 5/9
Moisture: 6/9
Nutrients: 7/9

Taxonomy resolved against GBIF.

Questions people ask

Can I grow this in my garden?: It is strongly discouraged due to its invasive nature and extreme health risks to humans and pets.
How do I get rid of it?: Professional removal is recommended, as any contact with the sap can cause severe burns.

Where the name comes from

The genus name Heracleum honors the Greek hero Heracles, reflecting the plant's massive size, while the species name mantegazzianum honors Paolo Mantegazza, an Italian anthropologist.

Good to know

It can grow up to 10 centimeters in a single day during peak season.
A single plant can produce up to 100,000 seeds in one season.
It was introduced to Europe and North America as an ornamental garden plant in the 19th century.
The stems are hollow and can reach 10 centimeters in diameter.

Also in

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This guide was generated with AI on October 19, 2026 and checked against GBIF taxonomy. It is general information, not horticultural or veterinary advice. Read about how we build these guides.