Whether it’s the century-old monkeypod trees that shade the driveway leading to the porte-cochere or the quietness of the valley, there’s a timeless quality to the grounds at the Manoa Heritage Center. The trees were planted by Charles Montague Cooke Jr., a descendant of wealthy missionaries, when he built the gracious, Tudor-style home on the property in 1911.

The current residents, Sam Cooke, 78, and wife Mary, 79, are the third generation of Cookes to raise their family in the home, which they refurbished 45 years ago. Having inherited his family’s love of history, Sam Cooke filled the home with paintings by Hawaii artists and a collection of Pacific navigation books.

“Houses like this don’t exist anymore,” he said, noting the exterior rock work by Japanese craftsmen. Other than plumbing and electrical upgrades, the home has been left as his grandfather, a noted Bishop Museum malacologist (someone who studies mollusks) built it. Today, Sam and Mary’s twin 8-year-old grandchildren are among those who love to explore the garden.

The home, listed on the National Register of Historic Places, will eventually be converted into a historical museum, but the Cookes have already been sharing the garden with schoolchildren and other visitors. They founded the nonprofit Manoa Heritage Center in 1996 to promote stewardship of Hawaii’s natural and cultural heritage. Spread over 3.5 acres, the garden showcases more than 30 species of native Hawaiian plants. Its centerpiece is the Kuka‘o‘o heiau, an agricultural temple restored in the early 1990s by rock masonry expert Billy Fields and believed to be the last intact heiau in the ahupuaa of Waikiki.

Standing in front of the stone heiau, visitors get a sweeping view of Manoa Valley and for a moment can imagine it as it once was, filled with terraces of taro. Guided tours of the garden and heiau are open to the public, with volunteer docents explaining the legends and natural history of Manoa and traditional uses of native plants.

Entering the garden through an iron gate, visitors take a stone staircase down to a clearing of plush St. Augustine grass with a stone bench and lily pond. Nicknamed the White Garden, it pays homage to Charles Montague Cooke Jr., who planted the magnolia tree that produces large, white blooms.

The Cookes’ contributions to the garden include Kauai white hibiscus, or kokio keo keo, which is endemic to Hawaii, and fragrant hibiscus. An endemic red ohia lehua replanted about seven years ago from a 3-gallon pot blooms during spring and summer. At about 20 feet tall, the tree is proof the species can grow in Manoa and not just at higher elevations.

A lava rock pathway, shaded by kukui and hou trees, passes by the meticulous layers of rocks that make up the lower heiau. Along the path is the Arbor, furnished with three stone benches originally cut as slabs for the home’s windowsills. The benches surround a konane, a Hawaiian board game similar to checkers.

Mary Cooke knows all the native plants by name but also has a penchant for the colorful orchids that fill a greenhouse and decorate the front of the home. Her father, William Moragne Sr. of Kauai, developed new plumeria hybrids in a mix of pinks, yellows and whites, naming them after the girls in his family. A small grove of plumeria trees celebrates his work.

The Cookes are also partial to the Kokia cookei, a small deciduous tree that no longer grows in the wild. Described as the rarest plant species in the world, it was discovered on a Molokai cliff in the 1860s and named after the family. When in bloom, its flowers are bright red. Other plants in the garden include ilima, with delicate orange flowers, and nanu, a rare native gardenia.

Landscaping staff trim the hedges and mow the lawns daily, while native-plant specialist Anthony Ortiz comes once a week. A tour of the garden ends behind the home at a section dedicated to Polynesian-introduced plants, or edible canoe plants. Ortiz has cultivated several varieties of taro, two types of sweet potato, as well as olena (ginger), sugar cane, a mountain apple tree and coconut trees.

The Cookes are planning to build a new visitor education center on the lot next door, plus a rain garden to absorb runoff, thanks to a donation by the Garden Club of Honolulu. Construction is expected to begin sometime this year.

The couple no longer walks the rocky pathways of their garden regularly, but visits the heiau from time to time. According to Mary Cooke, they enjoy spending time on their breakfast lanai, which looks out upon the monkeypod trees in front of the home.

The Manoa Heritage Center is at 2859 Manoa Road. Tours (by reservation only) are $7 for adults, $4 for seniors and military, free for children, students and school groups. Call 988-1287 or visit manoaheritagecenter.org.

“Garden Party” spotlights Hawaii’s unique and exceptional gardens. Call 529-4808 or email features@staradvertiser.com.