A toxic, invasive plant is proving to be a much bigger problem in B.C.'s Lower Mainland than officials thought, as removal crews find the giant hogweed population has doubled in the last year.

Giant hogweed is a native of the Caucasus Region and Central Asia and is believed to have been brought to North America for its seeds, which were once considered tasty.

However, the rest of the plant is wildly poisonous and the sap can cause blisters, long-lasting scars and — if it comes in contact with eyes — temporary or even permanent blindness.

Jennifer Grenz, who represents the Invasive Species Council of B.C. in Metro Vancouver, says July is a crucial time for removal teams, as some of the plants have gone to seed.

"Each plant...can have 100,000 seeds on it and those seeds can be viable in the soil for up to 10 years," she said.

"So as soon as you have a plant that's gone to seed and drops its seed, you're going to have a problem for many years to come."

The giant plants can grow to between two and five metres tall and due to their poisonous nature, they are extremely difficult to remove. 

Giant hogweed usually grows in creeks, ditches and vacant lots, but this year crews have seen them spread to popular walking trails.

Grenz says the Invasive Species Council of B.C. has been getting 80 calls a day since June, from people spotting the noxious plant in populated areas.

"There's a lot more than we really even thought, so I think we have a lot longer battle on our hands in terms of eradicating it."