In the early 20th century, an exotic Asian plant was brought to America for flower gardens and landscaping. Today, that plant has rapidly spread in many areas of the country. Giant hogweed, or Heracleum mantegazzianum, is causing both environmental issues and serious human health concerns.

Giant hogweed can grow to 12 feet or more in height. The plant has many large leaves at the bottom, grows a tall stalk and has a large white flower head.

The flowering giant hogweed is at least a five-year-old plant and can be as old as 25 years. The flowers bloom in June and July and seeds form in August.

On average, one giant hogweed plant can produce 20,000 seeds and there are some reports of upwards of 100,000 seeds from one plant.

Many of the seeds fall around the parent plant and some are carried by wind.

Amazingly, giant hogweed seeds are able to float up to three days in water and survive. This allows giant hogweed to quickly spread to new areas.

Giant hogweed prefers to grow in open areas with a lot of sunlight, but is also found growing in partially shaded areas. It prefers soils that are moist, but is not able to grow in places where there is standing water for much of the growing season. It can commonly be found growing in roadside ditches and along stream banks. Because giant hogweed grows so densely, it shades out native plants, destroying the habitat in areas that it infests.

Not only is giant hogweed a problem for the ecosystems of Cayuga County, but it can also be a serious threat to humans. Giant hogweed produces a clear, watery sap throughout the entire plant.

The sap contains chemicals that, when in contact with a person's skin and exposed to sunlight, can cause phytophotodermatitis, which is an inflammation of the skin that will blister and areas of dark pigmentation and scars will form.

The reaction can start in as little as 15 minutes after contact with its peak reaction between 30 minutes and two hours.

These scars and blisters can last up to six years and a person can suffer long-term sensitivity to light. Blindness can also occur if the sap gets into the eye.

If you come in contact with giant hogweed, you should wash the area with soap and cold water and contact your physician.

You should also avoid exposure to the sunlight to limit the reaction.

This past summer, giant hogweed was located in the Owasco Lake Watershed. Measures were taken to eradicate the plant from the area, but there is still the possibility that other plants exist.

To report giant hogweed in your area or for more information, contact the Owasco Lake Watershed Inspection program or the Cayuga County Soil and Water Conservation District at 252-4171.

Also, you can visit the New York State Department of Environmental Conservation's Web site at www.dec.ny.gov/animals/39809.html.

To obtain a brochure on Giant Hogweed, contact Cornell Cooperative Extension of Cayuga County at 255-1183.

Jessica Miles is the Owasco Lake Watershed inspector