Every spring, ads in Sunday newspaper supplements promise plants with unbelievable yields or fantastic blooms all summer. They boast of trees that grow as tall as a house in a single season.

One that's truly not what it seems is the "tree tomato," said University of Georgia expert Wayne McLaurin.

NO TOMATOES. The South American fruit, Cyphomandra betacea, is often called "tree tomato." But it isn't a tomato at all. "The fruit is more tart and jelly-like and has more seeds," says UGA horticulturist Wayne McLaurin.

"That old plant resurfaces almost every year," said McLaurin, an Extension Service horticulturist with the UGA College of Agricultural and Environmental Sciences. This year's ads list the plant as "Giant Tree."

"As usual, the seller promises yields up to 60 pounds per plant and stems that grow to 8 feet tall," he said. "The plants supposedly don't need staking or caging, either."

But it looks like the same plant McLaurin has seen before. "If it's what has been marketed before as a 'tree tomato,'" he said, "it's botanically known as Cyphomandra betacea, a very different species from garden tomatoes."

Actually, the "tree tomato" is a tropical, semiwoody shrub. It grows as much as 10 feet high and starts bearing fruit in the second or third year. However, the least amount of frost will kill the plant," McLaurin said.

And that's not all the of the bad news. "This plant is in no way related to the tomato," he said. "The fruit is more tart and jelly-like than our garden tomato. And it has many more seeds."

He smiles and shakes his head as he reads the ad closely. "They're sending out a seed planted in a pot at about $3.50 each (plus shipping)," he said. "That's one expensive plant."

McLaurin's advice to potential buyers is simple. Take care of your true tomatoes. "You'll be much happier," he said. "It's always wise to read all the fine print in these ads. And keep in mind that old saying, 'If it sounds too good to be true, it probably is!'"