Two by Noël Coward in repertory at Cygnet Theatre in Old Town

Cygnet Theatre offers a “double bill” of Noël Coward’s The Vortex (1924) and Hay Fever (1925). Staging his early plays in repertory has advantages. The dark, brittle Vortex is almost a photographic negative of the overtly theatrical Hay Fever. But the former has not worn well.

It’s tough to describe the effect Vortex had in 1924. The frank display of drugs and sexual promiscuity offended her so much, the actress cast as Florence Lancaster quit during rehearsals. The drama broke new ground for its openness about these subjects. And though it ends up with a tirade against immorality, many say it helped inspire Jazz Age behavior.

Don’t tell Florence she’s getting on in years. A lot like Arkadina in Chekhov’s The Seagull, she can’t accept aging. So she piles on make-up and takes younger and younger lovers. Her latest, Tom Veryan, is 24, the same age as her wayward son, Nicky.

He returns from Europe with a fiancée and a drug addiction (“I’m afraid I’m a little beyond aspirin”). He must convince his mother that their habits are “swirling on the circumference of beastliness.”

“Civilization makes rottenness so much easier,” he adds. “We’re utterly rotten — both of us.”

In the controversial third act, Nicky wants Florence not just to rehabilitate. “You’re going to be my mother for once,” he says, as if from Freud’s couch. “It’s about time I had one to help me before I go over the edge altogether.”

The Vortex was Coward’s first hit show. Today, it’s his least produced. What shocked in 1924 now plays heavy-handed. Acts One and Two ramble like apprentice work: people talk and dish in pairs. The third changes tone, and its over-inflated drama feels grafted on, as suddenly intrusive as a fire-breathing sermon on Fat Tuesday.

Coward said he just wanted to “write a good play with a whacking good part for myself.” He was Nicky in the original.

Cygnet director Sean Murray reset Vortex to the late ’60s. The change helps with the loose early scenes, as do Jacinda Johnston-Fischer’s splashy Mod outfits. Rattled Nicky’s a coke head; socialite Florence has affairs, but all we see is a kiss — which, in those free-loving times, wouldn’t raise an eyebrow, and which jars with the play’s relocation.

Coward wrote shallow people. Murray’s cast adds depth and subtexts where possible. As Florence, Rosina Reynolds plays the climactic scene with rich, emotional honesty. Though he tends to hard stress lines predictably, Charles Evans, Jr., does commendable work, though neither can reel in the melodrama.

Compared to The Vortex, Hay Fever is a bright, sunshiny day. The four Blisses are artists. They’re so self-centered, someone says, they “haven’t got one sincere or genuine feeling” among them. Where degradation lurks beneath the surface of Vortex, the Blisses are allergic to reality. Scratch their baroque surface and out pops uninhibited gaiety.

When each invites a weekend guest to their country house in Cookham, the Blisses live up to their name. They improvise scenes and wax madcap — at the expense of four puzzled, ultimately horrified visitors.

Coward boasted that he wrote Hay Fever in three days — in his bathtub. He could have; he laid the floorplan in Vortex. He just had to invert it. He morphed the decadent Lancasters into the devil-may-care Blisses. He based them on the “acrimonious” party games Laurette Taylor’s family played on weekends. She turned on every self-conscious guest, he writes in present indicative, “with proper abandon.”

So does Judith Bliss. The retired actress contemplates a return to the stage. Along with novelist husband David and their children Simon and Sorel, she makes scenes. The guests, anticipating an exciting weekend on the Thames just south of Oxford, find themselves trapped in an actor’s nightmare. Art, played to the melodramatic hilt, trumps life.

The Blisses’ odd behavior does have a moral payoff. Each guest brings a desire for personal gain. They are acting, too. Just not as well. They exit single file, chastened and shorn of illusions.

Directed by Rob Lutfy, Hay Fever’s fun, albeit often overdone. As if to heighten the differences between the two plays, the cast goes into display mode: they really strike poses. In the process, they add artifice to what already is artificial enough. Less would lighten the spirit and would also suggest underlying similarities between the plays.

Possibly even a third play, where the traits — of, say, Florence/Judith or Richard Greatham/Pauncefort Quentin (James Saba, excellent), Sorel/Bunty (versatile Rachael VanWormer), or Mura/Helen (Jill Van Velzer) — interweave as “sides” of the same multidimensional being.

Staging both plays in repertory requires contrasting styles and atmospheres. Sean Fanning’s handsome, glass-walled set fits both. As does a large portrait of Coward, on the rear wall, staring bemusedly down on what fools his mortals be.