On the mauka side of Lani­kai, two rain gardens recently built on the same street are quietly doing their jobs.

The basin-shaped landscape feature allows stormwater from roofs, driveways and other impervious surfaces to infiltrate into the ground or evaporate, mimicking natural processes. They keep pesticides, herbicides, sediments, pet waste and other pollutants from washing into storm drains and then into the ocean.

One of the rain gardens belongs to homeowners Jon and Jean Benfer, and the other to Steve Proctor and Margo Bare, who live a few homes down and across the street. One neighbor inspired the other, and both picked up shovels to help each other.

After a morning of digging up sod, they set up folding chairs for a lunch break beneath a pop-up tent. Other neighbors came by to watch, pitch in or drop off some food.

It was, in a sense, a rain garden party.

"It’s good to feel like you’re taking care of the ocean," said Jean Benfer, a recreational paddler. "It has been a nice way to start conversations with neighbors walking by."

Hui o Ko‘olaupoko, a nonprofit group whose mission is to protect ocean health, offers a co-op program that helps homeowners build rain gardens in their yards, providing the plants, soil and mulch as well as some labor and expertise. Funding is even available for proj­ects in Windward Oahu.

While doing duty by capturing stormwater, rain gardens can also be a landscape enhancement. Hui o Ko‘o­lau­poko uses hardy, perennial native plants such as ohai, pohina­hina, kokio (hibiscus), pau o Hii­aka, nanea and akuli­kuli (Hawaii desert thorn).

"The effects are greater if the rain gardens are grouped together," said Annie Lovell, project director for the hui. "If we had five in one neighborhood, you would see greater impact."

After creating a depression about 6 inches deep with sloping walls, weed-blocking fabric and edging are installed. Soil and plants are put in. Pipes may be installed underground and connected to downspouts to route stormwater into the rain garden; water also can be routed via surface flows over a rock-lined or grassy channel.

As water collects, it is filtered and slowly absorbed by soil and plants. If well designed, rain gardens will hold water for no longer than a day or two.

Working with Hui o Ko‘o­lau­poko, homeowners provide sweat equity, oftentimes recruiting neighbors and friends to help build the garden, which can typically be completed in one morning.

Benfer, 52, is a former Navy officer who’s been posted throughout the world, including Alaska, the Philippines, Italy and Washington, D.C. She took up gardening after retiring a few years ago.

Through the University of Hawaii, she became a certified master gardener in 2012, which involves about 42 hours of classes on a range of gardening topics, from rain barrel water catchments to soil preparation and integrated pest management.

It’s also where she learned of the rain garden co-op program. She decided it made sense for her own yard, which includes a nice expanse of green lawn that offers a peek of the turquoise ocean and Moku­lua islets. Besides areca palms along the back fence, there are six colorful plumeria trees and a garden bench beneath the shade of a 20-year-old mango tree.

The most unusual item is a life-size camel by Hono­lulu artist and friend Jackie Lau, which sits beneath a plumeria tree. A 4-by-8-foot raised vegetable garden was built by Benfer from a Home Depot kit.

The Benfers’ golden retriever, ‘Ula­‘ula, has the run of the fenced-in lawn, and neighborhood canine pals often come to visit.

The kitchen window looks out on the 120-square-foot rain garden. (Generally, the size of the garden is determined by the size of the roof or drainage area and soil type.)

Across the street, Bare and Proctor, having just finished a major remodeling proj­ect for their two-story home, decided it was time to jump-start their first landscaping proj­ect and that a rain garden would be the way to do it.

Theirs is smaller, measuring about 60 square feet, but is also positioned in the front yard. The couple completed theirs about a month after the Benfers.

Bare, an instructor at Hawaii Pacific University’s School of Social Work, said she was inspired by Jean Benfer to build the rain garden. Bare enjoys the ocean and her husband enjoys stand-up paddling, so they wanted to do their part in keeping it clean.

"You drive up and down the street, and you see people washing cars in their driveways, and that ends up in the ocean," Bare said. "We wanted to sweat some to do this."

Hui o Ko‘olaupoko also installed rain gardens in the parking lot at Buzz’s Lani­kai across from Kai­lua Beach Park, at Windward Community College and the Wai­kiki Aquarium. The group is looking for more homeowners on the Windward side with ideal sites to build rain gardens.

“Garden Party” spotlights unique and exceptional gardens. Contact us via email at features@staradvertiser.com or call 529-4808.