Otherworldly “trees” as tall as Aloha Tower, giant flowers fashioned from Lego blocks, close to 1.5 million real plants representing more than 19,000 species and varieties — all are in bloom at Gardens by the Bay, one of Singapore’s top attractions.

Singapore is half the size of Oahu but has four times the population — some 5.5 million people. Although its skyline is a parade of highrises, the concrete is balanced with an abundance of greenery and flora, creating a “city in a garden.”

Opened just 5 1/2 years ago beside the Marina Reservoir in downtown Singapore, Gardens by the Bay is a spectacular example of that effort.

“To me, the most wonderful aspect about the Gardens is their ability to inspire awe, delight and appreciation for plants in people who might not otherwise be interested,” said Janelle Jung, senior researcher in the Research and Horticulture Department. “We display some of the world’s most unique and culturally and historically significant plants in the world in an enthralling theme-parklike setting.”

Born and raised on Oahu, a “Palolo girl” who graduated from Punahou School, Jung holds a Ph.D. in plant breeding and genetics from Cornell University. She moved to Singapore a year ago to work at Gardens by the Bay.

Half of its 250 acres have been developed as a visitor attraction comprising two large conservatories, four smaller themed gardens, high-tech “Supertrees” and a children’s playground offering treehouses, a trail and a water play area.

Two serene parks in the other half of the Gardens are popular for strolling, jogging, cycling and picnicking.

Tight on time? Here are three must-see sights.

Cloud Forest Dome

Lush, green, veiled in mist, this 2-acre, 19-story conservatory recreates cool, moist tropical highlands. No pillars support the 2,577 glass panels used to build it, and its centerpiece is a mountain that’s encircled by two aerial walkways, blanketed with vegetation and refreshed by a waterfall cascading nearly 100 feet.

Showcased here are some remarkable specimens. The pretty sundew (Drosera spp.) is the femme fatale of carnivorous plants. On its bright green leaves are little red tentacles. The glands at the tips of these tentacles produce droplets of sticky digestive fluid that attracts insects. When a bug lands on the leaf, the tentacles and eventually the leaf itself slowly curl over, trapping the bug, which is digested by the plant.

Keep your eyes peeled for the alula (Brighamia insignis), which is endemic to Hawaii.

“Evolutionary biologists have rappelled down cliffs to pollinate it, since its natural pollinator is likely extinct, but the most recent surveys from 2014 show only a single wild individual on the Na Pali Coast,” Jung said. “Fortunately, this species has been saved from extinction through the combined efforts of researchers and horticulturists, and is prized in the horticultural trade as an ornamental plant and botanical curiosity. Our two alula are thriving, and they’re definitely among the Cloud Forest’s crown jewels.”

A thought-provoking message is shared in the Sixth Extinction exhibit: Earth has gone through five mass extinctions. Displays pose the question, are we in the middle of a sixth because of human activities such as pollution, population growth, habitat destruction and overuse of natural resources?

“Right now, species are likely going extinct faster than at any other time in Earth’s history,” Jung said. “Humans need to protect our environment and slow the loss of biodiversity — for our own selfish preservation, if nothing else. But this dire situation can be so overwhelming that it’s often easier to ignore it and hope the problem somehow solves itself.

“At Gardens by the Bay, we are taking a more encouraging approach. Our aim is to show our guests that — far from being boring green background — plants are wonderful creatures: beautiful, fascinating, precious and essential to our lives.

“We hope that in our gardens, guests find wonder; in wonder, appreciation; and in appreciation, the inspiration for personal action to care for our natural world.”

Supertrees

Rising up to 16 stories high, these 18 “vertical gardens” look like props on the set of a sci-fi flick, at once strange and wonderful. Wrapped around their trunks of steel and reinforced concrete are about 163,000 plants, including orchids, bromeliads and ferns in an array of hues. Their canopies resemble thin, leafless branches in the shape of inverted umbrellas.

The moniker “Supertrees” is even more apropos when you consider that 11 of the trees have environmentally sustainable features. Four are air exhaust structures for the conservatories; photovoltaic cells on the other seven harvest enough solar energy to light the trees in the evening and power a free, twice-nightly music and light show.

A dozen trees are clustered in the Supertree Grove, two are connected by a 420-foot walkway seven stories above the ground. From the walkway, the panoramic view of the gardens and the Marina Bay resort is equally breathtaking by day or night.

Plan on lunch or dinner at IndoChine, a bistro perched atop the tallest Supertree that serves Asian fusion cuisine (think lychee beignets with Kurobuta pork, fresh rice paper rolls with tiger prawn, and Japanese matcha cheesecake with roasted cashew nuts and chocolate ice cream).

Flower Dome

Take a thousand rainbows and release them in a glass building that’s big enough to hold 75 Olympic-size swimming pools.

This is the 3-acre Flower Dome — bright, airy, filled with a montage of vivid colors. Certified as the largest glass greenhouse in the world by Guinness World Records, it was constructed from 3,332 glass panels and replicates a cool, dry Mediterranean climate.

“Most conservatories or greenhouses are heated, making it possible to grow tropical plants in a colder climate,” Jung said. “Our conservatories are the opposite — they’re air-conditioned and covered with specially tinted glass to let light in but keep heat out, so we can grow and display plants from cooler, temperate climates, despite the eternal summer heat of tropical Singapore.”

The Flower Dome’s exhibits represent every continent except Antarctica. Don’t miss the Japanese camellia (Camellia japonica), native to China, Korea and Taiwan as well as Japan. Interestingly, it flowers in the cold, between January and March, which inspired its nickname “rose of winter.”

Hailing from New Zealand, Tahiti, Central America and South America is the fuchsia (Fuchsia spp.). Its pendulous blossoms resemble drop earrings, hence its nickname, Lady’s Eardrops. The small reddish or purple berries of most of its 110 species are edible and may be eaten raw or made into juice, jam and puddings.

Also of note is a gnarled olive tree from Spain (Olea europaea). More than 1,000 years old, it is the oldest plant in the gardens’ collection. And be sure to find the 32-ton African baobab (Adansonia digitata), often called the upside-down tree because its branches, when bare, look like roots. It stores water in its bloated trunk much as a camel does with its hump.

Exploring the Gardens

Gardens by the Bay is open daily. Hours for the Flower Dome and Cloud Forest are 9 a.m. to 9 p.m.; admission to both conservatories is about $21 for adults and $11.50 for children 3 to 12 years old.

The outdoor gardens are open from 5 a.m. to 2 a.m. Admission is free, including the music and light show held at 7:45 and 8:45 nightly in the Supertree Grove.

Tulipmania will be on view in the Flower Dome through May 13. Special exhibits coming up are Begonia Brilliance, May 25-July 1; Orchid Extravaganza, July 13-Aug. 22; Sunflower Surprise, Aug. 31-Oct. 21; and Poinsettia Wishes, Nov. 2, 2018-Jan. 6, 2019.

For information, go to gardensbythebay.com.sg/en.html.