Formerly owned by the McBryde Sugar Company, which bought the land from Queen Emma in 1886, this lush swath of Lawai Valley contains two major gardens worth visiting, as well as the headquarters and research facilities of the National Tropical Botanical Garden. The 186-acre McBryde Garden, open for self-guided tours on mostly unpaved trails, boasts the largest collection of rare and endangered Hawaiian plants in the world, plus numerous varieties of palms, fruit trees, heliconias, orchids, and other colorful flowers. Its Spice of Life trail, which includes cacao and allspice trees, meanders past picturesque Maidenhair Falls. The accessible Diversity Trail follows a 450-million-year timeline as it passes through a misty tunnel and ends at a pavilion with restrooms. Allow at least 90 minutes to explore.

Open only to guided tours, the captivating formal gardens of adjacent Allerton Garden are the legacy of wealthy Chicagoan Robert Allerton and his companion John Gregg, whom Allerton later adopted. Allerton bought the land from McBryde in 1938 and with Gregg designed a series of elegant outdoor “rooms,” where fountains and European statuary bracket plants collected from Southeast Asia and the Pacific. Garden tours last about 2 1/2 hours; 3-hour sunset tours begin in the afternoon and end with a peek inside the oceanfront Allerton estate (normally off-limits), plus appetizers and drinks on the lanai. A new, 2 1/2-hour guided Discovery Combination Tour offers highlights of both gardens, plus a peek inside the research-oriented horticultural center.

All valley garden tours require a tram ride and reservations by credit card. It’s free, however, to tour the Southshore Visitors Center Garden, where the trams depart. Although somewhat neglected, its several acres include separate areas for ornamental flowers and trees, a plantation-era home garden, Hawaiian native plants, and the profusion of color and textures known as the Gates Garden at the entrance.