A garden nursery in Burnaby, B.C., has discovered aggressive colonies of European fire ants on its property and is warning others to beware of this non-native species.

Fire ants may seem similar to native ant species. They are medium-sized and reddish-brown in colour, but when disturbed can swarm in the thousands.

Scott Pearce with Gardenworks says after the invasive ants were found, the nursery moved all their plants away from that area.
    
"We don't want those ants to be spread. We don't want customers or our staff to be subject to them at all," he said.

Fire ant expert Rob Higgins with Thompson Rivers University, says the ants are difficult to kill and can deliver a vicious sting to unsuspecting humans and other animals.

"In a single square metre you can have 4,000 or more ants that are ready to come pouring out to defend their territory," said Higgins.

"So when people sort of come in contact with a situation like that, the people lose fairly quickly."

Pesticides aren't effective and the ants' sting can hurt for hours and itch for days.

Higgins advises everyone to check potted plants before bringing them home.

With files from the CBC's Meera Bains