China does not have a national flower but debate is now under way as to whether the peony, considered a 'royal' flower on the mainland, or the wintersweet, a symbol of persistence in Chinese culture, should get the honor.

Meanwhile, Games organizers also have to be careful not to offend local sensibilities. A patch of white flowers would be considered offensive, as this is traditionally used at funerals.

"Red, pink, yellow and orange-colored flowers are our top choices," said Xu, who will help make the selections for the Games. "My foreign customers prefer light colors and odd-looking plants like dried bamboo sticks and willow twigs," said a local flower seller in Beijing.

The problem is that all these mutant strains pose a potential threat to Beijing's ecological system, according to some local experts. Xu says no way.

"About 76 percent of the flowers that will be used for the Olympics only live for one season, so playing with their reproductive calendar will have no negative impact on the environment," she said.

When Canada Goldenrod (Latin name: Solidago Canadensis) was tagged as an invasive alien flower that squeezed out homegrown varieties with its super adaptability to almost any environment, a national campaign was launched in 2002 to eradicate the flower from the country. Now China is more careful about introducing foreign species.

About half of the flowers being "groomed" for the Olympics are indigenous to China. The rest are imports.

Xu said none of the foreign varieties are overly aggressive.

"We carefully scrutinized the flowers' culture before importing them to make sure they can't branch off and find ways of independently adapting to Beijing's climate," she said.

The Canada Goldenrod, for example, may threaten local plants in wet and balmy Southern China, but not in arid Beijing, with its freezing winters. On the contrary, it would be a welcome addition to the city if it could somehow survive the harsh conditions.

"We would happy to have them here. They are useful to prevent desertification," said Xu.

Beijing has vowed to host a Green Olympics, and this remains more important than hosting a colorful Olympics, officials stress.

The government landscaped 130,000 square meters of rooftop gardens in 2007 alone and the rate is expected to rise in coming years.

"The city will keep on investing in these green projects," said Xu.