“Mother’s Day” is an ensemble holiday comedy packed with all the sappy sentimentality and mawkish manipulation that only the old master, Garry Marshall would dare give it.

It’s not very funny, and the plot points are so head-slappingly obvious that the audience is an hour ahead of the movie for most of its not-quite-excruciating two hour running time.

But it’s for Mom, so let’s all guilt ourselves into dragging her to it before the holiday it’s named for is here and the only movie options are about guys in tights and masks.

The “Valentine’s Day/New Year’s Eve” formula of interlocking stories returns for this Atlanta dissertation on the trials of motherhood, and the trials mothers can be.

Sandy (Jennifer Aniston) is the divorced mother of two, coping with the news that her ex-husband (Timothy Olyphant) has “married a tween.” Maybe she’ll be used to it “when her face clears up.” The new bride (Shay Mitchell) is young. Get it?

Jesse, played by Kate Hudson as if she’s doing an infomercial for her line of sportswear, and Gabi (Sarah Chalke) are sisters who live next door to each other. They have secrets. One’s married to an Indian-American doctor (Aasif Mandvi). The other’s gay and living with her partner (Cameron Esposito).

They both have kids, and they’ve never told their parents. Because, well, Mom and Dad (Margot Martindale and Robert Pine) are from Texas. They’re bigots. Get it?

A single-dad (Jason Sudeikis) plans on having his two girls ignore Mother’s Day since their military mom (Jennifer Garner) was killed in combat a year ago. Because the movie needs a dollop of sad, and Marshall loves to show how he supports the troops. And that gives Sudeikis the chance to play the awkward dad buying tampons for his teen, while Aniston, his “We’re the Millers” co-star, flirts with him. That’s comedy pre-packaged for your protection, get it?

There’s a young couple (Britt Robertson, Jack Whiteall) with a baby and no wedding rings. He’s an aspiring stand-up comic who tends bar, she’s a waitress who doesn’t know who her birth mother is.

And then there’s the infomercial queen, Miranda, played by Julia Roberts, given a wig and wardrobe that exaggerates her features into something tacky and a little frightening. She’s chosen “career” over motherhood, so she’s cold and a monster. Get it?

That gives Aniston and Roberts a chance for a couple of big-screen scenes together.

Marshall and his gaggle of writers are hard-pressed to find more than a giggle in all this. The stand-up comedy scenes are supposed to paint over that hole. Teens curse, a kid gets sick, and the Texans show up, letting the “trailer park” jokes pile up.

“I don’t get that joke, but it sounds racist.”

Martindale makes those scenes come the closest to working.

“And I put on a bra for this.”

Hector Elizondo plays Miranda’s agent, given to dispensing Hallmark card pearls of wisdom.

“We are who the world thinks we are. Or we’re not.”

Hospital scenes are peppered with hospital employees well past retirement age, many of them with “Marshall” as surnames. The director rounded up many of his equally elderly cronies and relatives with the promise of “I’ll PUT you in the movie.”

It’s all as predestined, slow-footed and played-out as People Magazine (equally played-out) naming Aniston its “Most Beautiful Woman” — again — cynically timed for this wilted daisy of a comedy’s release.

But will all that manipulation pay off at the box office? Why shouldn’t it? You’ve got to do something with mom after taking her to dinner on May 8. She’d better be an easy laugh, though. Otherwise, it’s “And I put on a bra for this?”

MPAA Rating: PG-13 for language and some suggestive material

Cast: Jennifer Aniston, Julia Roberts, Jaspn Sudeikis, Kate Hudson, Sarah Chalke, Britt Robertson, Margot Martindale, Hector Elizondo, Jack Whitehall
Credits: Directed by Garry Marshall, script by Tom Hines, Lily Hollander, Anya Kochoff, Matthew Walker. An Open Road release.

Running time: 1:58