Tropical Gardening Helpline: Suggestions for noise-blocking plants

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Dwarf bananas planted closely can block a lot of road noise. (wikimedia.org/via Diana Duff)
A wall of bananas makes a great noise barrier and offers fruit as a bonus. (Diana Duff/Special to West Hawaii Today)
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Lawrence asks: We are landscaping the yard at our new house and want to include a hedge between us and the street to reduce road noise. Any suggestions for good noise blocking plants.

Tropical Gardener answer: Good idea. Putting plants between you and a noise source can always help reduce your exposure to unwanted sounds. Noise buffering plants or structures that are at least five feet tall should offer effective sound reduction. Wise plant choice and placement can reduce noise by as much as 50%.

For best results, plant noise buffers close to the source of the noise rather than close to you. Including a fence or rock wall outside of the noise buffing plants is also helpful. Several rows of plants at different heights will help increase noise mitigation. Choosing plants with dense foliage or large leaves, can also keep down the noise inside the enclosed area.

Any plant you choose will have to be planted very compactly to be effective. This is especially true of clumping bamboos. You might want to consider podocarpus, privet or panax instead for complete coverage.

Evergreens have dense foliage year round. Junipers, cedars and arborvitae are all members of the Cypress family, have dense foliage and can block sound. The Italian cypress grows tall and narrow allowing for the density needed for noise abatement. Choose fast growing species and you should have excellent noise buffers in place within a few years.

Of course, it is always a good idea to consider multiple use plants to use as noise barriers. In windy areas, your noise blockers can also serve as windbreakers. Planting trees that attract birds can offer alternate sounds to the mix. Species that can offer occasional fuel, or posts or that offer edible fruit or nuts would also be wise choices.

Mac nut trees have dense foliage and offer a protein-rich food. Unless you keep lower branches in place, you might want to plant low growing shrubs between you and the trees. Keep the ground under the trees plant free so you can harvest the fallen nuts easily.

One of the best noise blocking plants that grows quickly here is the banana. This herbaceous plant contains more internal water than most others. Planting a row of banana plants tightly is essentially putting up a wall of water. Of course you’ll need to take down the trees to harvest the fruit, but new ones will grow quickly from the underground corms.

In drier areas you might want to consider a cactus as a wall of water. The treelike saguaro is particularly good at noise reduction as well as providing a thorny blockade against intruders. Plant an understory of Natal plum (Carissa) and you’ll have good thorny protection as well as some fruit for jelly making.

Whatever you choose to plant, the additional greenery will offer lots of benefits including beauty to your property.

Diana Duff is a plant adviser, educator and consultant living part time in Kailua-Kona.

Gardening Events

This week:

Saturday: “Work Day at Amy Greenwell Garden” from 9 a.m. to 12:30 p.m. Meet at the Garden Visitor Center across from the Manago Hotel in Captain Cook. Volunteers will be able to help with garden maintenance and are invited to bring a brown bag lunch. Water and snacks provided. Call Peter at 323-3318 for more information.

Tuesday: “Food Labeling and Food Safety” from 9 a.m. to noon at Hale Iako, Suite 119, NELHA (OTEC) Campus, 73-970 Makako Bay Drive, Kailua-Kona. Review of the Food Safety and Modernization Act compliance requirements including labeling as well as food safety plans. Fee $20. Sponsored by the Hawaii Small Business Development Center. To register go to https://clients.hisbdc.org/workshop.aspx?ekey=5400003. Call 808-333-5000 or email: dennis.boyd@hisbdc.org for more information.

Farmer Direct Markets

Wednesday: “Ho’oulu Farmers Market” 9 a.m. to 2 p.m. at Sheraton Kona Resort &Spa at Keauhou Bay

Saturday: “Keauhou Farmers Market” 8 a.m. to noon at Keauhou Shopping Center

“Kamuela Farmer’s Market” from 7:30 a.m. to 1 p.m. at Pukalani Stables

“Waimea Town Market” from 7:30 a.m. to noon at the Parker School in central Waimea

“Waimea Homestead Farmers Market” from 7 a.m. to noon next to Thelma Parker Gym in front of Thelma Parker Library.

Sunday: “Pure Kona Green Market” 9 a.m. – 2 p.m. at Amy Greenwell Garden in Captain Cook

“Hamakua Harvest” 9 a.m. to 2 p.m. at Hwy 19 and Mamane Street in Honoka’a

Plant Advice Lines

Anytime: konamg@ctahr.hawaii.edu Tuesdays &Thursdays: 9 a.m. to noon at UH-CES in Kainaliu – 322-4892

Mon., Tues. &Fri: 9 a.m. to noon at UH CES at Komohana in Hilo 981-5199 or himga@hawaii.edu

Photos:

Diana Duff is a plant adviser, educator and consultant living part time in Kailua-Kona.