SYRACUSE, N.Y. -- Plums, peaches, nectarines and cherries all grow on just one of Sam Van Aken's fruit trees. The trees blossom in a riot of red, white and pink each spring.

The artist calls his creations the Tree of 40 Fruit. And the tree at Syracuse University, and others like it, really does bear 40 or more varieties of stone fruit, thanks to carefully planned grafts.

The hybrid trees provide both juicy fruit and food for thought about preserving agricultural heritage. But most of all, Van Aken wants to provoke a response.

"When somebody happens upon it and they see it blossom in these different colours and they see it growing all these different fruit ... there's this rethinking, there's this sort of moment that sort of interrupts the everyday," said Van Aken, who teaches art at the university.

Van Aken's first 40-fruit tree has been located for the past four years on the edge of a campus green. On a recent broiling summer day, Van Aken plucked a few yellow plums the size of golf balls and ducked under a low branch to give a trunk-to-leaf tour. Starting with a plum root stock, he has over the years grafted on a cornucopia of fruit.

"Right here is a nectarine. It comes out on a plum base, but it continues to grow up here, until you have peaches on the end," he said. "There's a couple of apricots that have been grafted on, and this out on the end is a red-leaf plum variety."

The tree project is an outgrowth of Van Aken's work as a sculptor -- one used to working with nontraditional materials. Early on, he considered arranging different trees that blossomed at different times before realizing he could "collapse the entire orchard on to one tree." He decided to work with stone fruit -- that is, fruit with pits.

"It actually started with a Tree of 100 Fruit," he said with a laugh. "I was sort of ambitious."

He eventually settled on 40, a number rich with biblical allusions, such as the 40 days and 40 nights of rain when Noah built an ark and the amount of time Jesus fasted. Van Aken was inspired to include harder-to-find fruits after reading a century-old book, "The Plums of New York," that listed hundreds upon hundreds of varieties. The abundance was strikingly different from the few types of purple plums found in modern supermarkets.

He stocked the campus nursery where he works with antique and heirloom varieties, including some from a now-defunct research orchard. Over time, he has collected more than 40 varieties of plums, peaches, nectarines, apricots, cherries and almonds that he can graft to his trees.

The trees can turn heads in the spring, when the multicolored blossoms signal something unusual. But people who walked by the Syracuse University tree on a recent day barely looked up from their phones to notice the subtle differences in fruit from branch to branch. University employee Karen Davis said she had heard of Van Aken's tree, but walked by it at least twice a day without realizing it.

"I heard about the tree but I didn't know it was right here," said Davis, who called it "fantastic."

Van Aken said there are 16 trees sited around the nation, mostly in the Northeast. More are being grown and grafted in the nursery, including eight that will be planted in downtown Syracuse next year.

Several of the trees have been donated. The cost of the others depends on his travel expenses. Each tree is planted with 20 varieties grafted to it. He returns twice a year for three years after each planting to graft the rest of the varieties.

The trees keep him busy April through September, but he likes the fact that this is a unique type of sculpture that keeps on evolving.

"Every year it's something different. It appears different. It's radically different than it was six months previous," he said. "And that part has been the most rewarding part."