In Western Australia's South West, motorists can enjoy the sight of wildflowers that have been planted along the Bussell Highway.
The state's transport authority planted the native everlastings to improve soil quality.
However, people are enjoying the flowers so much that they are stopping to pick them, which Main Roads says is "dangerous" and "illegal".
The popular drive between Bunbury and Busselton, about 200 kilometres south of Perth, has become more scenic, with the median strips awash with blooming everlasting flowers.
But Main Roads WA has criticised the risky behaviour of motorists who are pulling over on the Bussell Highway to grab handfuls of the flowers.
Regional director Dominic Boyle urged people to leave the flowers alone and not create unnecessary hazards on the road.
"Not just because it's illegal to pick these flowers, but also they are putting themselves in danger."
Mr Boyle said the decision to plant flowers, rather than shrubs, to revegetate the median strip on the Bussell Highway, was unusual.
Everlastings were chosen because they were hardy and would improve soil quality.
However, reports of ardent flower pickers stopping to gather blooms have alarmed the agency.
"There's a big safety concern. We also want to make sure that seed gets back into the soil," Mr Boyle said.
"So we really encourage people just to keep themselves safe and to leave these flowers alone."
The City of Bunbury has also planted the everlastings on its road reserves and the flowers are proving popular.
Bunbury Deputy Mayor Cheryl Kozisek took a positive approach to reports of flower theft.
"I think it's a real compliment that people are picking them," she said.
South West Wildflower Society's Kelly Paterson said people illicitly picking wildflowers was an issue throughout the region.
"It's a disappointing thing to see. "Taking those flowers before they are able to set seed means that seed is not going into the seed bank to produce additional plants in the future."
Commercial flower seed supplier Jen Egerton-Warburton said picking wildflowers on other people's land was not on.
"It's kind of rude, isn't it? Someone else has planted them, for you to go and pick them, so I don't think it's appropriate.
"I don't think it's appropriate to pick any wildflower in Western Australia that is not in your garden.
"If people want to pick wildflowers, grow them at home."
The Department of Biodiversity, Conservation and Attractions said Western Australia's native everlastings were protected.
"It is an offence to take native flora, including wildflowers, from Crown land, public reserves and road verges without lawful authority," a spokesperson said.
Penalties can be significant, with fines of up to $50,000 for unlawfully taking native flora and up to $500,000 if critically endangered flora is involved.