Idina Menzel Broadway musical is thin, sappy

The title character of “Redwood,” the musical that opened Thursday night at the Nederlander Theatre, is a humongous northern California tree. 

Onstage, the centuries-old conifer enters dramatically like a wooden grande dame and towers over the five actors. The majestic set piece by designer Jason Ardizzone-West is so big, star Idina Menzel and the rest are able to scale it using ropes and harnesses. 

Too bad the Broadway show named after the wooden giant is a toothpick. 

The story of a collapsing New York woman named Jesse (Menzel), who escapes west to the forest on the first anniversary of her son’s death, “Redwood” is a shallow exploration of grief that’s as obvious as its sledgehammered central metaphor: She’s the tree, roots and all. 

Falling apart, Jesse hops in the car without telling photographer wife Mel (an underused De’Adre Aziza) about her spontaneous journey to the other coast. Not even a “so if you care to find me, look to the western sky.” 

Once in Eureka, Calif., in the wilderness strikingly depicted on large screens, she stumbles upon a pair of scientists. 

Despite traveling thousands of miles to take a hike, Jesse’s not a nature girl. “I hate greenery,” she proclaims. “If I even think about grass, I get Lyme Disease.” 

Indeed, writer-director Tina Landau has all her characters abruptly announce their defining traits like they’re on “The Dating Game.” 

When Jesse meets Finn (Michael Park), a veteran climber and optimist, he proudly says, “Got my head in the clouds!” 

His younger colleague Becca (Khaila Wilcoxon), irritated and skeptical, quickly retorts: “Got my feet on the ground.” 

Got my head in my hands. 

Jesse, normally a risk-averse workaholic, is immediately compelled to ascend the redwood that the duo has been studying. Finn, a kindhearted hippie, is on board with the idea. But rule-abiding Becca is adamantly opposed. (Clouds! Ground!). That muddled character, whose volcanic anger only exists to drum up conflict where there otherwise is none, is the worst-written in the show. 

Wilcoxon wows anyway with her powerful voice, but it gets wasted on composer Kate Diaz’s loud and repetitive ballads. One, in which Becca explains how the redwoods witnessed “human history’s growing pains,” is a lecturing “We Didn’t Start The Fire” that packs in the birth of Jesus, the writing of the Magna Carta and the Civil War. Lofty! 

Predictable as sunset, Jesse still goes up and Menzel straps in. The aerial sequences, in which the actors push themselves off the tree and spin around while accompanied by lush orchestral music, are supposed to be euphoric and life-affirming. “I’m flying, Jack!” That kind of thing. At best, however, they’re surreal. 

Menzel’s songs are tailored to the actress’ pop belt, which is thrilling in parts and wobbly in others. As she wails lesser versions of “Defying Gravity” and “Let it Go,” you sense the creative team’s mantra was “give the people what they want.” What we want, though, is Menzel now — not Menzel in 2003. I was worried she wouldn’t make it through some of the trickier numbers. She moves closer to 2025 with her maternal acting. 

Alone and making camp hundreds of feet in the air, Jesse battles the unforgiving elements and her own buried fears and insecurities. In a stormy monologue, Menzel vulnerably inhabits a mother who’s both running to and from the memory of her son Spencer, even if her quick-cut, poetic speech could end with “Moo with me!” 

The musical, which premiered in San Diego last year, also presciently concerns west coast wildfires.

There’s trauma after trauma. Yet what’s so puzzling about “Redwood” is that it’s a textbook tearjerker — a mom in mourning rediscovering herself midair, weighty speeches about losing everything — that leaves your eyes totally dry. 

The closest the musical comes to being remotely affecting is a quiet song toward the end called “Still,” beautifully sung by Zachary Noah Piser as Spencer. 

Jesse’s winding explanation for her son’s death should be scrapped and completely rewritten, but Piser has a velvet voice and an easily emotional presence regardless. 

“Redwood” gave me a renewed appreciation for “Into the Woods” and its composer-lyricist Stephen Sondheim. His show has the same themes, and the song “No One Is Alone,” softly sung by Cinderella, is a wise meditation on loss among the leaves that goes straight for the soul. 

There’s nothing half so deep from Elsa.