Salt-tolerant plants best in coastal yards

By Heidi Bornhorst

Dear Miss Heidi: We love the beach. My husband surfs and I gain inspiration for my art by being close to the salty ehukai wind, taking a walk on the beach which is right outside our door and so on. But now, surfers delight, the waves are attacking my yard; my plants are eating it! Even the naupaka and "railroad vine" are salt-soaked with brown sunburnt leaves. What should I grow? What can I do?

— 'Ehukai in Hale'iwa

The tough, salt-repelling leaves and white blossoms of the kamani tree do well in O'ahu's coastal areas. Advertiser library photo • May 2001

Get out the garden hose and rinse the excess salt off your plants. The naupaka and railroad vine (pohuehue or beach morning glory) are well adapted to these conditions, and they will recover once the highest waves subside. Rinsing off the salt will do a lot to save your plants — and refresh you.

Choosing tough salt-tolerant plants will make gardening less stressful during the high surf season. This is a great time to look around your neighborhood and see what plants are doing fine in the salty sunshine.

Native Hawaiian coastal plants such as your naupaka and pohuehue are great, adapted and thriving under these conditions. They may look bedraggled now but they will probably recover and put out even stronger leaves. Beach vitex or kolokolokahakai (the name means traveling alongside the beach), 'ilima papa (the low, ground-hugging, coastal form), hinahina, nehe, 'ohai and other native coastal plants should do well. Low growing, silvery leaved plants such as our beachside natives, often are salt- and wind-tolerant and their low form also helps them thrive.

Look for plants with waxy or tough salt-repelling leaves: Plumeria, crotons, tiare or tahitian gardenia all like some salt in their diet.

Many Polynesian-introduced plants do well along the sea. Kamani, milo, hala, niu and kou all do well. Kukui, which many people think of as a mauka plant, does well at the coast, too.

Tahinu or beach heliotrope is related to natives hinahina (the lei flower of Kaho'olawe) and kipukai. It has silvery leaves and high salt and wind tolerance. You see this small tree all along the windward coasts and on the North Shore.

There are all kinds of beachside gardens and the degree of saltiness and salt winds that they are exposed to.

A Waikiki garden, with occasional salty kona winds, is very different from one in Waimanalo or along the beach in Kailua, with their nearly constant onshore salty winds. Kahuku usually is super windy and salty.

The North Shore usually gets kind of a side salty breeze, but the big waves that pro surfers crave can come right up into your garden. Wai'anae side gets yet another wind exposure and this pattern is present in various forms on Neighbor Islands, too. Figuring out the conditions of your garden and what thrives best there is part of the fun of island gardening.

Other microclimates exist within your garden. And do use the hose: Simply rinsing and refreshing your plants is one of the best and easiest things a Hawai'i gardener can do.

Heidi Bornhorst directs Honolulu's five botanical gardens. Reach her at heidib@hawaii.rr.com.