Priscilla Growney has always had a way with plants, indoors and outdoors. This week she’ll test her gardening mettle as a first-time participant in the Garden Club of America’s Major Flower & Horticulture Show over Mother’s Day weekend.

The show, taking place at the Honolulu Museum of Art, is presented only once every three years by the Garden Club of Honolulu.The 2015 show is themed "Shangri La: The Flower Show" and coincides with a museum exhibit titled "Doris Duke’s Shangri La: Architecture, Landscape and Islamic Art" which showcases works from the late philanthropist’s personal collection. It is the first time the pieces have been displayed outside her Black Point estate, known as Shangri La.

As part of the garden show, the museum’s Mediterranean courtyard will be transformed into a Persian flower garden.

"It challenges you," said Growney, 75, of the competition. "This year is so exciting because of the theme and connection with the museum."

Besides spectacular displays of floral design and plant specimens, there will be exhibits of botanical photography, jewelry and, for the first time, needlework.

Growney, a certified master gardener, is entering plants in more than five classes in the horticulture division, including a crown of thorns she dug up from her yard to compete in the "euphoria" class and three plants in the "longevity" class that she’s been growing for more than a year.

This year’s "rejuvenation" challenge, which requires entrants to grow a particular plant from seedlings distributed by the club, spotlights the Acacia koaia, a rare species of flowering tree in the pea family that is endemic to Hawaii. The koaia tree provides habitat for the Kame­ha­meha and Blackburn’s butterflies.

The National Tropical Botanical Garden on Kauai donated 100 seedlings for the challenge.

Growney, the garden club’s horticulture workshop chairwoman, is participating in all of the above and entering a needlework, as well. She said that recently reaching the milestone of 75 is "no excuse to slow down." On some Saturdays she serves as a "plant doctor" at the Kapiolani Community College Farmers Market. She also teaches ikebana, the Japanese art of flower arrangement.

"She has boundless energy," said sister Diana Jardine, also a garden club member, as was their mother, who taught them the botanical names of plants.

At her Diamond Head home, Growney has cultivated an edible garden in the backyard with fruit trees from Frankie’s Nursery in Wai­ma­nalo and beds of celery, sweet potatoes, arugula, tomatoes and nasturtiums, which climb up a bamboo teepee.

A striking, potted desert rose, given to her seven years ago by local businessman Thurston Twigg-Smith, sits next to the swimming pool. She wanted to enter it, but transporting the 400-pound plant to the museum proved too much of a challenge.

Two Alcantarea odorata, a rare bromeliad, are planted beneath a corner of the home. These large plants with slender, pointed leaves bloom only once in five years before dying. Growney will not dig them up for the competition, but has potted specimens she’ll be carefully transporting to the museum to enter in the "majesty" class.

Judges use magnifying glasses to examine the bromeliads, assigning scores based on how well they are centered in the pot, uniformity of leaves, presence of a natural, silvery-white powder finish, and other criteria. Although members covet the recognition of a major show win, it’s all for the fun and learning, according to Growney.

The Garden Club, with about 82 active members, offers opportunities to meet other gardeners and for community involvement. Members organize horticulture classes at Lyon Arboretum and participate in conservation efforts. Six years ago, for instance, members grew kukui trees from seed and planted them at what is now the Leahi Millennium Peace Garden at Diamond Head. The grove is thriving.

After this competition, the koaia saplings will be donated to Papahana Kuaola, the nonprofit arm of native plant nursery Hui Ku Maoli Ola in Kaneohe.

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