Environmentalists are going on the offensive against several plants which have invaded central Scotland.
Contact with the giant hogweed causes skin irritation
Japanese knotweed and giant hogweed, which is poisonous, were first introduced to the country as ornamental garden plants.
But they are now regarded as invasive weeds which create problems to health and the environment.
Now the Stirling Landfill Trust has embarked on an information campaign to eradicate the fast-growing plants.
Contact with the sap of giant hogweed, which can grow as tall as five metres, can cause skin to blister, especially in sunlight.
Stirling Landfill Trust project manager Audrey Morrison urged residents in the area to keep a look out for the plants.
She said: "Of course Japanese knotwood is quite pretty in its way - that's before it grows underneath your house and comes up through your foundations and asphalt.
"Both plants are very invasive and so fast-growing they shade out native flora."
The plants often take over riverbanks, causing problems for fishermen and walkers.
Japanese knotweed forces out native plant life
The giant hogweed's large flower stems clog rivers and weirs and in winter the weeds die back, leaving the bare riverbanks at risk of erosion.
The plants were originally brought to the UK by the Victorians - avid plant collectors who sought out exotic species from around the world.
Ms Morrison said anyone discovering the plants should not panic, adding: "They can be treated with a herbicide containing glyphosate which you can buy in any garden centre or supermarket."
She said giant hogweed was best treated now, at the start of the growing season, while Japanese knotweed should be sprayed when all the leaves are out.
They should then be left to die off before being burned or buried.
The landfill trust's campaign has been backed by both Stirling Council and environmental body Scottish Natural Heritage.