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Giant Hogweed

Heracleum mantegazzianumQuick ID:

Giant Hogweed

A member of the carrot or parsley family, a perennial with tuberous root stalks.
Stalks and stem are hollow, stems vary from two to four inches in diameter.
May grow 15 to 20 feet tall, except for size it closely resembles cow parsnip.
Has stout dark reddish-purple stem and spotted leaf stalks

Habitat:

May colonize a wide variety of habitats but is most common along roadsides, rights-of-way, vacant lots, streams and rivers.

How It Got Here:

Originally from Asia & introduced as an ornamental.
Planted as a curiosity in European and North American private gardens early in the twentieth century.

Reasons for Concern:

Giant Hogweed is a public health hazard due to it’s clear, watery sap which has toxins that cause photo-dermatitis.
Skin contact followed by exposure to sunlight produces painful, burning blisters that may develop into purplish or blackened scars.
Applicators must be careful with removal of this plant.

Video: Controlling Invasive Plants – Giant Hogweed

What is stem injection?

Stem injection is a process by which herbicide is injected directly into a plants hollow cane. This unique method is particularly effective with the invasive plant species know as Japanese knotweed. By injecting herbicide into the plants crown, as apposed to an external application you increase the transfer of herbicide throughout the plant systems roots. Not only is stem injection more effective then other forms of herbicide but since the application is done within a plants crows as applied to being applied via a spray it poses less of a threat to the surrounding vegetation. To learn more about how stem injection works click here.

Japanese Knotweed

The Japanese Knotweed is a bright green plant with a hollow stock similar to that of bamboo. Often Japanese Knotweed can grow upwards to 16 feet tall and spreads by means of its root system. Additionally Japanese knotweed and its hybrid the Bohemian knotweed can be identified by its spade shaped leaves as well as by the off white flowers that grow around the plants branched. Because the plant has few natural predators it has spread throughout North America To learn more about this invasive species click here.