Residents are being warned to be on lookout for the “UK’s most dangerous plant” as fears emerge about giant hogweed growing in Dumbarton’s canal stretches.

Giant hogweed, which can grow up to five meters high and is common in green areas, has been spreading through the UK recently as a result of hot weather.

However, with green leaves and small white flowers, giant hogweed can often be mistaken for cow parsley or common hogweed which is harmless and regularly found along Dumbarton’s canal stretches.

Giant hogweed made national headlines two years ago when a 10-year-old girl suffered severe burns from the plant sap in Loch Lomond.

This week, passers-by mistook common hogweed for giant hogweed on the pathways opposite the Vale of Leven Academy and Jameston Road.

This was reported to West Dunbartonshire Council but was found to be harmless.

The plant has a thick stem and a height of up to five meters whereas common hogweed will not grow taller than two meters and has a much thinner stem.

Common hogweed has a “hairy” stem whereas giant hogweed will be smooth with bristles at the leaf joints.

The toxic plant will also have up to 50 flower stems whereas common hogweed is likely to have around 12 to 15.

Giant hogweed can also be identified by its purple hue stem.

A spokesman from the council said: “Common hogweed is a harmless plant, although it is often easily confused with giant hogweed.

“There is a helpful guide available on the council website which highlights the differences between common and giant hogweed.

“Any residents who spot giant hogweed on council-owned land are asked to report it via the ‘contact us’ area of the website or by calling Greenspace on 01389 608413”

Giant hogweed can be harmless if left undisturbed however the hairs on the stem and the sap inside the leaves, which contain toxic chemicals called “furanocoumarins”, can cause burning, itching and blistering if they come into contact with skin.

Effects can be especially severe in warmer weather when exposure to the sun makes the skin sensitive.

If residents spot giant hogweed growing their garden a strong weed killer can be an effective way of getting rid of it.

Herbicide is the most commonly used control method of giant hogweed however, it is best to ask for advice when purchasing in order to get the most appropriate product.

Cutting the plant is not recommended as this will expose the toxic sap which is the most dangerous part of the plant.

It is also advised that giant hogweed is not placed in a compost or brown bin.

A spokesperson for the Scottish Wildlife Trust said: “The main thing for members of the public would be to avoid touching or cutting giant hogweed plants, and if they do come into contact with it to cover the exposed area and wash with soap and water, as advised by the NHS.”

Giant hogweed can also have harmful effects on dogs as the animals may eat it or run into the plant getting the sap in their eyes.

Symptoms of giant hogweed sap may not appear straightaway, however if you believe your dog may have had contact with the toxic plant it is important to see a vet as soon as possible.