Carolyne Roehm's mother advised her to live in Montana and grow roses. And, says the designer who's striking enough to be a runway model, maybe Mama was right.

"It certainly would have been a less hectic and demanding life," muses Roehm as she sits in her Manhattan office. "Fashion's a tough, hard profession - 14-, 15-hour days - and there's a lot of criticism that can really hurt. When people in this business tell you they aren't affected by cutting comments - well, it's just a bunch of baloney!"Despite criticism and long hours, though, Roehm loves fashion designing. Quite honestly, there never has been anything else she wanted to do.

Born Carolyne Jane Smith, she grew up in the Midwest. Clothes quickly captured her fancy - she loved to play dress-up - and she first exhibited her natural talent by creating hats at her grandmother's sewing machine.

After taking liberal arts courses in college, it was off to New York to try her luck in the garment industry. The first job? Boring! It lasted two days. The second wasn't much better.

"They wanted me to design cheap polyester sportswear and that just wasn't what I had in mind," Roehm explains frankly. "I tried to sell them on doing better merchandise, but they weren't interested. So, instead of being miserable and frustrated, I decided to change and work for somebody who was turning out the type of clothing I admired. . . somebody like Oscar de la Renta. Once I'd seen a picture of the model Lauren Hutton in a de la Renta dress. It was elegant; exactly the sort of thing I longed to do."

Mustering her courage, Roehm called the fashion house and finally managed to get an interview. To her amazement and delight, things clicked.

"Oscar became my teacher, my mentor, my dear friend," she says. "He opened doors for me in this industry. I owe him so much."

Don't think, however, that Roehm started at the top or that success came overnight. De la Renta was a tough teacher and a great believer in giving his talented young pupil a fashion education "from the ground up." At first it was a matter of running out for sandwiches, substituting as a fitting model, helping with shows, working over patterns.

"I really did it all," Roehm recalls. "Finally, I graduated. Oscar let me paint scarf designs, work with licensing and help him choose fabrics and embroideries. The responsibilities increased every day. It was exciting, wonderful. I absorbed it all just like a sponge!"

Marriage to Axel Roehm, heir to a German chemical fortune, interrupted the apprenticeship. But the marriage was short-lived, and soon Carolyne Roehm was back on Seventh Avenue - busily working her way up to chief designer and head of Oscar de la Renta's lower priced Miss O line.

The young designer also assisted her mentor with his higher priced collection, but after about 10 years decided to take the big gamble and move out on her own.

"I was eager to express my own fashion vision, not Oscar's," Roehm explains. "Much as I admired him, I realized it was time to do my own thing."

Of course, there were doubts and fears. Fashion's a field where young designers can flash like bright meteorites on the scene - and burn out just as fast. Roehm's the first to admit she was one of the lucky ones. Her designs caught on immediately. Her financing sources worked out. And shortly after launching her own line, her good fortune in professional life carried over to her personal life as well with a happy marriage to millionaire businessman Henry Kravis.

Today she's is well established in the American fashion community and her firm is rapidly expanding (an accessories line was launched for spring and shoes are in the works for fall of '89).

Her styles, costly and elegant, are coveted by women of means and leading socialities who always fill the front row seats when new collections are introduced.

"I've never been a great believer in ruffles and that sort of thing," Roehm says. "My tastes run more to the simple silhouette that emphasizes the woman not the dress."

The designer does believe in lavish embroidery, however, and often has the famous French House of Lesage do the jeweled embellishments that appear on garments in the collection.

As for lengths, the topic that has filled fashion columns for so long, Roehm favors short and has shown it even when other designers have wavered. She thinks it looks young and fresh and modern. It also makes practical sense, in her opinion.

"A lot of women invested a great deal of money in short lengths," says the designer. "I do not think this industry can say short is dead after just a season or so and remain credible. So, for fall of '88, I stuck with short and for spring of '89 my clothes for street wear are only slightly longer. Even for fall of '89, I'll probably offer both short and long and plenty of pretty pants."

And, yes, there will be numerous outfits for glamorous evenings parading down the runway when Roehm shows her new fall styles in April. Active on the social circuit herself (she's perhaps the busiest hostess in New York and almost always there when a charity bash is given), the designer has a special affinity for party clothes.