The riotous foliage that practically engulfs “Suddenly Last Summer,” with its enormous ferns and squawking beasts, looks as if it has been airlifted into a New Orleans backyard directly from Jurassic Park. “There are massive tree flowers that suggest organs of a body, torn out, still glistening with undried blood, “Tennessee Williams wrote in the stage directions to his 1958 hothouse of feral sexuality and Oedipal longing, which has now received a pulse-slowing revival at the hands of director Mark Brokaw.

The central skirmish in this Southern Gothic potboiler may be waged with words, but it does its untamed setting justice. Williams managed to distill the dichotomies that so often engaged him — truth vs. power, acceptance of life’s seamier attempts at transcendence vs. blue-nosed rigidity — into a slim, faintly ludicrous 90 minutes. He did this by having an enterprising young neurosurgeon who goes by the nickname of Dr. Sugar (Gale Harold) referee a battle royale between two strong-willed women who embody these traits, each holding her share of family secrets.

In the (stage) right corner: Violet Venable (Blythe Danner), the wealthiest woman in the Garden District. An unfailingly polite gorgon whose domineering habits have been only slightly curtailed by a recent stroke, Violet has invited Dr. Sugar to her lush backyard (Santo Loquasto’s set design is suitably over-the-top) to discuss funding his clinic … along with another small matter.

In the (stage) left corner is that other matter: her traumatized young niece Catharine Holly (Carla Gugino), who has returned to America after spending the summer globe-trotting with Violet’s son, a Dorian Gray-style aesthete named Sebastian Venable. He had always traveled with Violet in the past, but the aforementioned stroke — she prefers to call it “a little vascular convulsion” — rendered Violet unsuitable for reasons that will grow clear.

Cathy has been locked up in a private sanitarium since returning, largely because of her eagerness to discuss the events that led to Sebastian’s horrific death in a squalid harbor town named Cabeza de Lobo. Her description of the “finer things” that Sebastian sought varies quite a bit from her aunt’s, and her scandalous tale has motivated the powerful Violet to inquire about Dr. Sugar’s revolutionary research in quieting agitated minds via lobotomies. (Williams set the play in 1936, when the technology was brand new — and only a few years before his own beloved sister, Rose, was lobotomized.)

The small-minded grotesques that Williams loved to include make an appearance. (Wayne Wilcox and especially Becky Ann Baker are strong as Cathy’s money-grubbing brother and mother.) More to the point, so is the icon of steely yet deluded femininity that Williams returned to again and again: With her regal bearing and her mania for propriety in the face of deviance, Violet Venable could be an older, marginally more stable Blanche DuBois (a role that Ms. Danner, in fact, played in 1988).The formidable matriarch clearly holds the upper hand in her battle with Cathy, and so Mr. Brokaw attempts to muffle the still-vibrant Ms. Danner in various ways, with mixed success.

Her breathy rushes of dialogue work well enough; Ms. Danner convincingly portrays a woman who has not yet realized that her days of Southern loquacity lie somewhat in the past. For every magnolia-scented “conflagration” or “mendicant”that spills off her tongue, far simpler words stop her cold mid-sentence, and her gasping attempts to finish the thought convey the ravages of age.

But Ms. Danner’s primary bit of physicality — a rigidly held rictus in her left hand, with two fingers perpetually jutting out as if holding an invisible cigarette — is an unconvincing and distracting mannerism, the sort of actorly detail that can easily slide into fussiness. Violet’s fearsome reputation can’t help but suffer when her “vascular convulsion” appears to have occurred in the middle of a game of Rock, Paper, Scissors.

Her account of the previous summer takes up the play’s first half, at which point Cathy arrives to give her own lurid version. This latter telling remains one of Williams’s most stagebound sequences, a fact that the 1959 movie dodged by interspersing Cathy’s monologue with extensive flashbacks to Cabeza de Lobo. (These involved several shots of Elizabeth Taylor in a skimpy white bathing suit; fans of Ms. Gugino should be forewarned that these flashbacks do not exist in the play.)

Mr. Brokaw tries to vary the scene by having his agitated confessor wander all over Violet’s garden, including up and down a spiral staircase. But this kinetic staging wouldn’t be necessary if Cathy’s story were paced with the appropriate modulations. Ms. Gugino — who conveyed emotional instability beautifully as the Marilyn Monroe surrogate in 2004’s “After the Fall,” also presented by the Roundabout — starts at something close to a fever pitch here, giving her no direction to go except up, up, up. The head-to-head battle against Ms. Danner’s compromised but cagy Violet suffers as a result.

Except that Williams intended “Suddenly Last Summer” as a head-to-head-to-head battle, with Dr. Sugar assuming an increasingly pivotal role as the play builds to its salacious conclusion. Fundamentally decent yet dependent on Violet’s largesse, clearly attracted to the woman he’s asked to evaluate (Cathy’s shapely knee buckles involuntarily as he gives her an injection), the terse but tender doctor finds himself literally standing between the two combatants.

The intensity of these opposing desires becomes clear only in the play’s final seconds, when the central dilemma suddenly rests on his broad shoulders. He finds himself in a sort of “Lady or the Tigress?”situation, and the only hints to its resolution stem from Dr. Sugar’s actions along the way.

This is where Mr. Harold’s cautious, subdued performance falls short. Despite displaying an effortless physical comfort on stage, the actor, best known for his caddish role on TV’s “Queer as Folk,” keeps his motivations frustratingly opaque. The film got plenty wrong, but Montgomery Clift turned Dr. Sugar into an equal partner in the Freudian fireworks display, a truth-seeker frantically searching for a resolution that will make him morally as well as financially secure.

Perhaps Mr. Harold has intentionally kept the drama at arm’s length as a counterweight to the histrionics on either side of him, and matching their intensity might have proved disastrous. But with just a spoonful of Sugar, Williams’s salacious melodrama doesn’t go down as smoothly or as satisfyingly.

Until January 14 (111 W. 46th St., between Sixth and Seventh avenues, 212-719-1300).