Greenway art needs to grow

The resulting sculpture installation, “Urban Garden,’’ is timid at best, save for one piece. That’s a pity, because the Greenway has wonderfully revitalized areas of downtown Boston that were once forbidding, and it’s the perfect platform for offering intriguing public art to make people stop, think, and feel.

Tom Otterness’s “Tree of Knowledge’’ is the only sculpture in the group of three works with teeth. Otterness, a nationally known public artist, slyly deploys cute figures to make cutting social commentary. The cheeky “Tree of Knowledge,’’ a 9-foot-tall bronze tree populated with critters, needles the justice system. A blind bird holds the scales of justice as a menacing snake slithers toward it up the tree trunk. A beaver and a possum, both in business suits, represent lawyers. The beaver gnaws away devilishly at the tree’s base.

But the other two works, James Surls’s 14 ½-foot-tall abstract wheel, “Walking Flower times the Power of Five,’’ and John Ruppert’s four giant gourds in the “Pumpkin Series,’’ are pallid, vanilla offerings that few are likely to remember in years to come.

“There’s room for whimsy in Boston,’’ says Nancy Brennan, the conservancy’s executive director.

We have whimsy, with “Make Way for Ducklings’’ in the Public Garden. Boston deserves public art with real heft and wit - especially now that there’s ample space for it along the Greenway.

“We wanted something for everyone,’’ says Nick Capasso, the deCordova’s deputy director for curatorial affairs, and the curator of “Urban Garden.’’ “This is not the most cutting-edge contemporary sculpture. That’s intentional. The idea is to please the public.’’

Visitors to the Greenway on a recent afternoon did seem pleased.