Bouquets of purple blooms spotted alongside roadsides during spring should not be mistaken for wildflowers.

They are a ‘fasciation’ of Paterson’s Curse, the noxious weed that plagues pastures in Western Australia and other Eastern States.

Department of Agriculture and Food, Western Australia weeds researcher Sandy Lloyd said that spring usually prompted calls from the public about the plant.

“Some people report it, thinking that it is a mutant or ‘triffid’ Paterson’s Curse plant,” she said.

“But there is no cause for concern. It is not a sign that the dreaded Paterson’s Curse is evolving into a super weed.”

Ms Lloyd said fasciation was the result of damage to the growing tip of the stem of the young plant.

“It is not known how the damage is caused, but it could be due to insect attack or disease. Instead of growing from one point, the stem of a fasciated plant grows from many points.”

Other weeds that commonly show fasciation are flatweed and skeleton weed, but they do not provide such an impressive display as Paterson’s Curse.

Ms Lloyd said fasciated Paterson's Curse plants could be spectacular, especially when the plants flowered, developing a staghorn shaped display of tiny leaves and a mass of purple flowers.

Paterson’s Curse is one of the most conspicuous weeds of pastures and roadsides in Western Australia. It is a declared plant in this State, and costs sheep and cattle producers millions of dollars every year in lost productivity in pastures, wool contamination and control measures. It is also toxic to livestock, particularly horses.