Expect a spectacular garden display to sprout inside the Hono­lulu Museum of Art over the Mother’s Day weekend.

It will include exhibits of flower arranging, horticulture, photography and botanical jewelry as well as a special exhibit promoting sustainable growing practices.

The Garden Club of America Major Flower & Horticulture Show, presented by the Garden Club of Hono­lulu, returns to the museum Friday through Sunday.

It is one of only nine major flower shows being held in the nation this year and happens only once every three years.

This year’s theme, "Echoes of Rainbows," was inspired by a Peter Moon song and reflects Hawaii’s diversity of native flora and the optical phenomenon so often seen in isle skies.

More than 100 club members are participating in the show, which features five divisions, each of which includes several categories of competition.

In the floral arrangement division, for instance, displays in the "Prism" class must be suspended in air. Entries must be visible underwater for the "Water" class and focus on a color of the rainbow for "Spectrum."

In the horticulture division, look for gold-toned flowering specimens of the oncidium orchid in the "Pot of Gold" class, and parent-and-keiki pairs (where a "keiki" plant is propagated from a parent plant) under "Reflections."

The "Eat Your Greens" category calls for edible plants displayed on a tabletop framework. Members competing in this class have filled eight planter boxes with edible plants — each with a different theme, such as nasturtiums (florals), Hawaiian (kalo, uala, akulikuli) or pesto plants (arugula, sorrel, watercress and spinach).

The emphasis of major flower shows today is as much about education as it is about spectacle. While the garden club’s goal is to broaden the knowledge of horticulture and floral design among its members, a key part of its mission is to promote sustainability and conservation.

"We are careful to not include any invasive plants or flowers in our exhibits," said co-chairwoman Dotty Nitta, a nationally recognized garden show judge.

You might be surprised to learn what’s on the list of invasives: Hilo grass, christmasberry, white ginger and rose myrtle.

Nitta and co-chairwoman Victoria Hill helped steer the organization’s members through a maze of strict regulations and requirements for each exhibit.

Floral arrangements must be executed on site, for instance. Botanical jewelry cannot include glitter or locally invasive plant material.

All entries must have been owned and grown by the exhibitor a minimum of three months in advance of the exhibit (and six months in advance to qualify for some awards). They must also have the correct botanical information (including genus and species) on the entry card.

"It takes creativity, but you need to do your research, too," said Hill.

Seventy judges from the mainland will select the winners. Besides best in show, there are novice awards and various medals and certificates of excellence in horticulture, photography and conservation.

This year’s conservation/education exhibits are titled "Colors of Sustainability."

The first celebrates gardens in schools as a way to educate future generations about nurturing the land and where their food comes from. The second features more than 20 kinds of succulents arranged on letters that spell "grow." The display reuses lumber from an exhibit taken down from the museum.

Its purpose is to illustrate how succulents use less water, as well as how planting a vertical "living wall" can take up less space than a horizontal garden.

Some setbacks suffered by gardening enthusiasts this year included the onslaught of hail that fell on Windward Oahu during a thunderstorm in March, which ruined some garden club members’ plants.

The museum held its first flower show in 1931, shortly after the Garden Club of Hono­lulu was accepted into the national organization.

While most club members in those days were ladies who supervised yardmen and wore hats and white gloves to meetings, today they are passionate, hands-on horticulturists who reach out to the community.

This year, club members also wanted to send a message about sustainability by creating unique, colorful sculptures out of recycled plastic bottles. Members diligently collected hundreds of bottles; spent hours painting, cutting and putting them together; and gave the sculptures a tongue-in-cheek botanical name, "Recylocium plastica (Landfiller)."

The sculptures will be strung up at the entrances to various exhibits in the gallery to add color as well as remind the audience of how much space plastic bottles take up in landfills.

For the 2009 flower show, members grew kukui from seed, which are now planted at the Peace Garden at Diamond Head. This year, members grew loulu palms from seed and will also plant them in a public setting after the show as part of the club’s ongoing legacy.

In conjunction with the garden show, the museum’s Doris Duke Theatre will present a Garden of Cinematic Delights Film Festival featuring movies about gardening and humans’ connection with nature.