Giant hogweed
Heracleum mantegazzianum · Apiaceae
The gardener's calendar
Ideal time to plant giant hogweed: set it out when the soil is neither frozen nor waterlogged, and water generously as it establishes.
ID card
- Foliage
- Deciduous
- Blooming
- June to August, white flowers in umbels
- Adult size
- 1.5 to 2.5 m in height
- Growth
- Very fast
- Hardiness
- Very hardy (down to -20°C)
- Origin
- Caucasus
- Soil type
- Rich, moist, well-drained
- Exposure
- Full sun to partial shade
Care
Watering
Caucasian hogweed appreciates constantly moist soil, especially during spring growth. Water regularly during dry periods, but avoid waterlogging. In temperate climates, natural rainfall is generally sufficient once established.
Exposure
Choose a location in full sun or partial shade for optimal growth. The plant tolerates partially shaded areas well but flowers more abundantly in sunlight. However, avoid overly hot exposures in Mediterranean climates.
Pruning and cutting
No pruning is necessary. Simply remove faded flowers if you wish to prevent significant self-seeding. Cut the plant down to ground level in late autumn or winter when the foliage dries completely.
Soil
Choose soil rich in organic matter, moist and well-drained. Adding compost at planting time promotes establishment. The plant adapts to many soil types but dislikes prolonged drought.
Fertilizer
A moderate application of balanced fertilizer in spring stimulates growth. A layer of compost on the surface before the growing season is generally sufficient for established plants. Avoid excess nitrogen, which would promote foliage at the expense of flowering.
Diseases and pests
Caucasian hogweed is generally robust. Watch for slugs and snails in humid periods, as well as aphids in spring. No major fungal diseases typically affect this species under normal conditions.
Did you know?
Caucasian hogweed is notorious for its invasive nature: introduced to Europe in the 19th century as an ornamental plant, it escaped from gardens and aggressively colonizes natural habitats, forming impenetrable single-species stands. More remarkably, its sap contains phototoxic furanocoumarins that cause severe burns when skin exposed to sunlight comes into contact with it, making it a "plant at risk" to handle with caution.
Where to buy it
Plant in spring or early autumn, avoiding spells of intense heat. Pick a plant with healthy foliage and roots that are not exposed. Best time: March, April, May, September.
Add this plant to my garden →Plants from the same family
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Tips generated and checked by Viridia — adapt them to your local climate.