Giant Hogweed
Giant Hogweed (Heracleum mantegazzianum, also giant cow parsley) is a plant in the family Apiaceae, native to the Caucasus Region and Central Asia. It may reach 2-5 meters (rarely to 7 m) tall. Except for size, it closely resembles Common Hogweed (Heracleum sphondylium), Heracleum sosnowskyi or Garden Angelica (Angelica archangelica).
Description
Giant hogweed (Heracleum mantegazzianum) is a poisonous, invasive, exotic species. It is a perennial in the carrot and parsnip family like cow parsnip, which it resembles, although it is much less poisonous. Giant hogweed can measure from two to five meters high, or thirty centimetres to one meter after mowing. Its very robust stem is covered with stiff white hairs and numerous, very distinct, extensive, raspberry-red to purple spots. Its leaves can be up to 1.5 meters wide and three meters long. It flowers from late spring to mid summer, with numerous white flowers clustered in an umbrella-shaped head that is up to 80 cm (2.5 ft) in diameter across its flat top. The plant produces 1,500 to 100,000 flattened, 1 cm long, oval dry seeds that have a broadly rounded base and broad marginal ridges. Shoots die down in the autumn. Tall stems mark its locations during winter. Flowering only once in its lifetime and reproducing only by seed.
Often mistaken for
Giant hogweed has been mistaken for other species, especially others in the carrot family. These species include; Angelica, Wild carrot (daucus carota), Goutweed (aegopodium podagraria), poison hemlock (conium maculatum), water-parsnip (sium suave), spotted water-hemlock (cicuta maculata) and angelica (angelica atropurpurea). Once again, its "giant" size is the easiest distinguishing feature, as it towers above these other species.
Habitat
Giant hogweed was introduced from Europe, presumably as an ornamental, and has escaped along roadsides, stream banks, ditches, along railways, in fields, vacant lots and waste areas.
Toxicity
Phytophotodermititis can develop up to 48 hours after exposure to sap. It is characterized by localized rash and oedema (red, swollen skin), blisters, or even burns. Once healed (in approximately a week), brown spots can persist and the affected region can remain sensitive to sunlight for several months. All parts of the body can be affected, but the back of the hands, arms, legs, and face are the most commonly injured because they are more likely to be exposed to the poisonous sap and to sunlight.
What to do in the event of exposure
If your skin has been in contact with sap
- Remove the sap as quickly as possible without spreading it. Use a sheet of absorbent paper and do not rub. Wash the affected area with soap and rinse thoroughly with water.
- Then wash your hands. Change and wash your clothes to avoid contaminating other parts of your body or other people.
- Cover affected areas (gloves, long pants, and long sleeves) to avoid exposing them to light (including artificial light) for at least 48 hours.
If your eyes have come in contact with sap
- Rinse your eyes thoroughly with clean water for ten minutes.
- Wear dark sunglasses to avoid exposing your eyes to light.
- See a doctor as soon as possible.
If you must handle the plant, protect yourself:
- Cover your body head to toe with protective, nonabsorbent clothing (synthetic, waterproof material): long pants, long sleeves, and waterproof gloves with long cuffs.
- Pay special attention to areas where your protective clothes overlap (wrists, ankles, neck).
- Remove your clothes and gloves by turning them inside out. To prevent contamination, avoid putting soiled clothes in contact with other objects or clothing and wash them well before any further use.
- Protect your eyes or, even better, your entire face (visor).
Useful links:
http://www.msss.gouv.qc.ca/sujets/santepub/environnement/index.php?gberce-du-caucase-en.
http://www.dspq.qc.ca/documents/Berce_du_Causase_fiche_Web.pdf.
http://www.cbif.gc.ca/pls/pp/ppack.info?p_sci=comm&p_type=all&p_psn=195&p_null=&p_x=px&p_lang=.
http://www.mddep.gouv.qc.ca/biodiversite/nuisibles/berce-caucase/tableau-comparatif.pdf
