Giant Hogweed
Heracleum mantegazzianum
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Its sap causes severe burns that recur in sunlight for years. Do not touch it.
An enormous biennial or perennial umbellifer reaching five metres, with thick hollow green stems blotched purple and covered in coarse bristles, huge jagged leaves up to a metre and a half across, and vast flat white flower heads. Introduced from the Caucasus as an ornamental, it grows along the Nith and other riverbanks and on waste ground around Dumfries.
Behaviour
The sap contains furanocoumarins that destroy the skin's protection against ultraviolet light. Contact followed by sunlight causes severe blistering burns, and the affected skin can remain sensitive and re-blister for years afterwards; sap in the eye can cause blindness. Never strim or cut it. It also seeds prolifically along watercourses and shades out native bankside plants.
When to see it
Quick facts
- Family
- Carrots (Apiaceae)
- Height
- Up to 5 m
- Status
- Invasive non-native; sap causes severe burns — do not touch
Photo by Lucas Kendall, CC BY-SA 4.0, via Wikimedia Commons