Kenneth and Patty Kupchak of Kai­lua are lifelong hikers, so it was only natural that their garden reflect the flora they appreciate along the trails.

Front and back, the yard of their 7,700-square-foot property is full of many of the same native plants found on Oahu’s uppermost ridges and in its verdant valleys.

Along with a small strip of grass out front, the Kupchaks have akia, a low-maintenance ground cover that mingles with ulei, an indigenous Hawaiian hawthorn with glossy green leaves and clusters of white blossoms. There are also a few slow-growing loulu palms with fanlike leaves, the only palms native to Hawaii, and uki uki, or Hawaiian lily, with purplish-blue berries that are used as kapa dye.

"I enjoy hiking, so I want to have the plants I enjoy hiking with," said Patty Kupchak. "Hawaii’s plants are unique, and most are found nowhere else in the world."

The striking lau hala tree that greets visitors on the left side of the driveway was planted from a seed Kupchak found while hiking in Kahana Valley in the ’70s. It anchors the garden as well as a number of colorful orchids Kupchak grafted onto it with bark cloth.

More than a dozen ohia lehua trees, a species of evergreen in the myrtle family, also grow in the front and back yards. When in bloom in spring, they offer bright red and yellow blossoms.

"The ohias are my favorite," said Kupchak, 69, a self-taught gardener.

She has a library of gardening books and learned mostly by trial and error. She also credits the late naturalist Lorin Gill, a close friend, for teaching her about the many native species.

Gill was the founder of the Hawaii chapter of the Sierra Club and is considered by many as the father of environmental education in Hawaii. He died in October 2010 at age 82.

"Whenever you hiked with Lorin, he would tell you things about the plants, the legends, geology and biology," she said. "While hiking with him you eventually absorbed it all. That’s the best way to learn."

Kupchak volunteers at the Hawai‘i Nature Center in Makiki and co-chairs a forest restoration committee that removes invasive species from Hawai‘i Volcanoes National Park.

Her husband, Kenneth Kupchak, 72, is president of Hono­lulu law firm Damon Key Leong Kupchak Hastert. Before becoming an attorney, he studied chemistry and meteorology and served as a meteorologist for the Air Force and the University of Hawaii.

They’ve hiked practically every trail in Hawaii since 1971, serving as hike leaders for the Sierra Club and advising the group’s high school hiking program. Both their sons grew up hiking.

To fulfill their interest in natural history, the adventurous couple also backpacked in various parts of the world, including Bhutan, Tasmania and the Arctic National Wildlife Refuge.

ONE OF PATTY Kupchak’s prized specimens is an ihi­ihi­lau­akea, an endemic fern found along the Ka Iwi coastline at Maka­puu which resembles a four-leaf clover. The plant was added to the federal endangered species list in 1992. Kupchak acquired hers from the native plant nursery Hui Ku Maoli Ola in Kane­ohe, one of her favorite places to shop.

"We couldn’t sell the place because I couldn’t leave the plants," said Kupchak, referring to their home of more than 40 years.

Not every plant and tree in the garden is native.

Kupchak loves the fragrant, yellow-green paka­lana, also known as Chinese violet, and so she has a vine growing along the fence. Most passers-by notice the generous Pope mango tree while passing the side of the yard.

Any mangoes hanging low along the perimeter probably will be gone before they are ripe, said the Kupchaks. Luckily, a bed of lauae ferns cushions the ones that fall inside the yard.

In the backyard, Kupchak has an acacia koaia tree, a rare, smaller cousin of the large forest koa, and native shrubs such as ala­hee, mountain nau­paka and naio papa.

Most of these native plants seem to thrive in the area.

"That is the beauty of the native," said Kupchak. "You really don’t have to take care of it once it’s established."