Summertime, and theater is easy. Real easy. At least it is at Olney Theatre.

For its annual musical, the Maryland playhouse has revived the 1983 off-Broadway hit "Little Shop of Horrors" for a run through July 13. Gleefully macabre in spots, this is nonetheless a small show that will most likely appeal to those with a hearty appetite for low camp. Those who have never had any luck with house plants and suspect them of possessing perverse minds of their own may also respond. If nothing else, the musical vindicates all of us who have suffered pangs of guilt for letting a geranium die.

The villain of the evening, you see, is a perfectly disagreeable potted plant named Audrey II that appears to be a cross between Ollie (as in Kukla, Fran and . . . ) and a Venus' flytrap. Mushnik's Skid Row Flower Shop, where the musical is set, is about to go bankrupt, when nebbishy Seymour, the florist's apprentice, stumbles on Audrey II in a rainstorm and puts it in the shop window. Customers start turning up in droves and before long, Mushnik's is being asked to supply all the flowers for the floats in the Rose Bowl parade.

Seymour blossoms, too, and it looks as if he just may rescue the bleached blond cashier at Mushnik's (she's named Audrey, as well) from a life of degradation and settle down with her in a tract home with "a fence of real chain link."

There's one hitch in the scenario. Audrey II doesn't respond much to Miracle Gro. Water leaves it indifferent. Only human blood seems to bring a blush to its tendrils. "Feed me," growls the increasingly aggressive plant, which proceeds in the second act to sing "Suppertime," while rocking and rolling like a chubby teen-ager at the prom.

Inspired by the similarly titled, next-to-no-budget 1961 horror film, "Little Shop" is largely a single-joke musical. But the musical is brief enough that the joke doesn't entirely wear out its welcome. Howard Ashman, who wrote the book and lyrics, gets most of his laughs by underscoring the lower-class aspirations of his characters. At one point, Seymour (Jesse Foreman) rues his lack of life experiences, adding that he's "never had a fancy dinner at Howard Johnson's." Cheap, but good-hearted Audrey (Kirsti Carnahan) dreams of a place of her own, but "not fancy like Levittown." You get the idea.

The creators of "Little Shop" are not aiming high. Fortunately, they're not mean spirited. The show is an amiable bit of slumming and you can admire its cleverness. You can also come away wishing there had been more.

Alan Menken's score, a pastiche of 1960s pop music, doesn't boast any particularly memorable numbers. But it has energy, a beat and a kind of sleazy bravado, best voiced by Tichina Arnold, Tisha Campbell and Michelle Maria Weeks, as a synchronized chorus of Skid Row urchins. With "Somewhere That's Green," Audrey's hymn to a better life, Carnahan neatly expresses both the character's deep feelings and her arrested IQ. Foreman isn't much of a singer, but he compensates with jerky charm, whipping off his spectacles with reckless courage when it comes time for him to kiss the girl.

By then, he's won Audrey away from her boyfriend, a "semisadist" called Orin, whose idea of jewelry is a pair of handcuffs. Orin rides a motorcycle and wears leather by night. By day (this ought to peg the show for you), he's a dentist. Tony Rizzoli plays him with maniacal zest. Watching him sniff nitrous oxide, go into a shiver of ecstasy and then dissolve in mindless giggles amused me as much as anything else. (That, too, ought to be a clue.) Rizzoli does less well by a handful of other cameo roles, but Irwin Ziff sports the mad demeanor and fly-away hair that are appropriate for Mushnik. He's the nutty professor as a florist.

The direction by Bill Graham Jr. is serviceable, although the sets by Tom Donahue are shabbier than the circumstances require, especially when Mushnik's becomes New York's In florist shop. Still, you don't ask a lot of "Little Shop," probably because it's not asking a lot of you. Pleasantly, albeit forgettably, gruesome, it offers a change of pace, some amusingly tawdry diversions and the chance to get back at your begonias.

Little Shop of Horrors, book and lyrics by Howard Ashman; music by Alan Menken. Directed by Bill Graham Jr.; musical direction, Rob Bowman; sets and lights, Tom Donahue; choreography, Carole Lehan; costumes, Patrick Wiley; puppets, Martin P. Robinson. With Tisha Campbell, Michelle Maria Weeks, Tichina Arnold, Irwin Ziff, Kirsti Carnahan, Jesse Foreman, Tony Rizzoli, Michael Lehan, James Petosa. At Olney Theatre through July 13.