Of all the lovable things about the 1997 musicalization of Marivaux’s The Triumph of Love, that waltz-time Act 2 serenade to a severely laced little topiary may be the most lovable of all. Two stern rationalists—Helen Hedman’s brittle, barriers-up Hesione and her ascetic-philosopher brother, Hermocrates (Stephen F. Schmidt)—look glumly at a potted boxwood that they’ve been torturing into some arcanely significant shape, and in a string of lilting, half-completed, minor-key musical thoughts, they wake up to the notion that there’s something sadly incomplete about the poor plant’s circumscribed life, just as there is about their own. Dedicated life-of-the-minders both, they’ve each been awakened to passion by the story’s schemer-in-chief—a princess who, in romantic pursuit of their scholar nephew Agis (Jake Odmark), has talked her way into their no-visitors-allowed retreat, claiming to be a prospective student one minute and a fugitive from an arranged marriage the next. This Leonide (Patricia Hurley) has a fetching song or two herself, as do the henchmen of various loyalties who join forces to help ensure that all ends well, but for my money the show works best when it stops elbowing the audience in the ribs and holds still long enough to display the big, sorrowful heart on its sleeve. “The Tree,” along with a shatteringly good Act 1 ballad called “Serenity” (in which Hesione first lets down her emotional guard) are the songs where that heart beats strongest, and though everyone in Clay Hopper’s crisply staged, gorgeous-looking production at the Olney Theatre Center is doing good work, it’s those delicately shaded moments of rapture and rue, starring Schmidt and especially Hedman, that I’ll tuck away in memory to revisit now and again.