A monster plant with white flowers in the shape of an umbrella and sap that can cause severe burns and possible blindness is rearing its dangerous head this summer.

In the Capital Region, state Department of Environmental Conservation crews, with the help of homeowners, are making sure giant hogweed plants in Albany and Rensselaer counties are cut back or sprayed, said Naja Kraus, the department's giant hogweed program coordinator.

The plant, once used as an ornamental feature in backyard gardens, is believed to be spreading throughout the state. DEC is receiving more calls on its hotline as the public learns about its dangers.

The threat is more serious than the rash caused by poison ivy and poison oak, Kraus said Tuesday.

"It's different because (giant hogweed) changes your skin, making it more susceptible to the sun for a number of years," she said. It's a condition known as photo-dermatitis, sensitivity to sunlight.

"If the sap gets on your skin, and the sun shines on your skin, especially if there's moisture like sweat -- and it needs the sun -- it makes the skin unable to protect itself from sunlight, and you can get third-degree burns and blisters," Kraus said.

If the sap comes into contact with the eyes, it can cause eye irritation and "can lead to blindness," she said. DEC officials know of no case in the state where blindness was linked to the plant, she said.

"The big difference is poison ivy rashes are itchy and irritating, but a giant hogweed is a burn," she said.

The blisters are painful for a time and can result in permanent scarring, mostly on the arms and legs, exposed areas of the body. The DEC website, which has extensive information and photos of the plant, said contact between the skin and the sap occurs "either through brushing against the bristles on the stem or breaking the stem or leaves."

Native to the Caucasus Mountain region between the Black and Caspian seas, the plant is identifiable by giant leaves that produce white flowers that are in bloom at this time -- from late June to mid-July.

The DEC is in its fourth year of a control program, starting in 2008 with a federal grant of $40,000. Funds that supported last year's and this year's programs of six crews totaling 14 people who will visit most of the 944 sites in the state, are $763,000 in stimulus funds, Kraus said. There is no funding for next year.

Giant hogweed has been around for 100 years, brought to this country in the early 20th century, "because it's an amazing ornamental plant. It can grow to 14 feet tall," and was used "as a showpiece for ... flower gardens," Kraus said. The flower head can be 21/2 feet across and shaped like an umbrella. Once in the United States, seeds were distributed to both botanical gardens and home gardens.

In Altamont, a giant hogweed was planted in a home's garden, and when new owners bought the house, one of them got burned. It was reported to the state Department of Agriculture and Markets which controlled it the first year. Last year, DEC went in, and since then, the homeowner "is doing a great job" controlling it, Kraus said. A DEC crew still checks on it.

The first year, 30 big plants with big flower heads were removed, she said. Last year, there were 20 to 30 smaller plants, but by spraying them, they did not flower. The plants can be attacked either by digging up roots or spraying with herbicides. What comes back each year are new plants from seeds, that are in the soil. It could be a number of years before all the seeds sprout, Kraus said.

The other local plant being controlled is at a home in Averill Park. Last year, DEC crews worked on a big flowering plant and a number of smaller plants, and this year it's being watched. "We have no idea how it got there," Kraus said.

"It takes each plant three or four years to get enough energy in its roots to flower, and there's enough time to cut through roots or spray before it will flower," she said.

Once it flowers, the individual plant dies, but younger ones are growing from seeds, which can be found within 30 feet of the parent plant.

In Salem, Washington County, less than 20 plants have been reported at a home, but the homeowner refuses to let DEC control it, Kraus said.

Sightings of the plant are more prevalent in the central and western parts of the state where large sites of five or more acres in fields or along stream banks can be found, she said.

The 2-to-4-inch stalks of the plant are hollow, and the hotline received a report that kids were using the stalks as telescopes, putting them up to their eyes, Kraus said.

If giant hogweed isn't enough to look out for, try another dangerous plant called wild parsnip, found along roadsides and in fields. This plant also has the "same ability to cause burns" and is common around the Capital Region.

Reach DeMare at 454-5431 or cdemare@timesunion.com.