They're causing serious damage to wildlife and river banks.
Invasive species are threatening our biodiversity across the midlands.
Japanese Knotweed and Himalayan Balsam are two particular plants that are taking over and destroying native wildlife.
They don't have natural predators to control them and can quickly dominate, upsetting eco-systems and eroding river banks.
While the Himalayan Balsam can be pulled, Offaly Heritage Officer Amanda Pedlow is warning people not to touch Knotweed.
She says if you think you've spotted some, send a picture on to the County Council and a trained professional with treat it:
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