Invasive Species on Kaua’i


Strawberry Guava. Java Plum. African Tulip. They sound like lovely, lush, exotic plants at first glance. In fact, they are just a few of Kaua’i’s invasive species that grow so big, so fast, and so quick, other other plants can’t survive.

Below are  just a few common Invasive Species on Kaua’i.

Removing a thicket of Hau Bush

Hau Bush

These ‘bushes’ can grow to be up to 100 ft. trees, thriving in wet, standing water, or drier terrain. This species spreads by a branch falling over and taking root on the earth, creating a new mother plant. The Hawaiian Dictionary describes Hau as “some spreading horizontally over the ground forming impenetrable thickets,” (p. 60, Pukui, Elbert).

Guinea Grass

Also known as Buffalo Grass, this species can reach up to 15 feet in height, with clumps of dense grass which contain tiny, razor-like spikes on the blades which resemble fiberglass.

When the grass flowers, the seeds blow in the wind, creating more grass wherever they land. This grass can be found in most of the old sugar cane lands on Kaua’i.

Java Plum

Of the largest trees growing in Hawai’i, Java Plum trees grows fast to looming heights. The species takes over by spreading the messy, acidic, grape-shaped plums on the earth below. The plums (and the tree’s leaves) are so acidic that it’s hard for other plants to grow in the surrounding soil. Java Plums can create a canopy so thick it shades the forest from getting light to grow more varieties underneath.

Shredding a field of Guinea Grass

The Problem With Invasive Species

They can cause massive soil erosion. The invasive species grow so dense that they block out the sunlight from reaching the ground below, preventing stabilizing ground cover to root. When no ground cover roots over, the soil is left with bare, loose dirt for chickens and pigs root up, and then heavy rains causing unstable earth that ultimately ends up in Kaua’i’s rivers, streams, and into the ocean.

 Invasive Species choke out native, sustainable plants and inhibit natural diversity in the Hawaiian landscape.

They make gardening and farming a battle.

Solutions to Combat Invasive Species

• Shredding smaller species. Any of the invasive species listed above with trunks 8 inches or less in diameter can be shredded instantly, and be spread as mulch or as ground cover. Up to 24 inches in diameter can be fed into a wood chipper

• Removing larger species. Excavators and other machines can be used to remove the species, the stumps, and the root systems. If the tree is simply cut or bush shredded, it will simply grow back if the roots are not removed.

• Maintenance. After removal, the area can be seeded with grass or some type of ground cover. Once the soil is stabilized, the land is ready for planting.

What are the invasive species where you live?

About the Author

Lois Ann EllLois Ann Ell is co-owner and office manager for RYLO Excavation & Landscaping, specializing in communications and public relations. She is a graduate of the University of Hawai’i at Hilo with a degree in English with Writing Emphasis, and a certified mediator in alternative dispute resolution. Lois Ann is a writer for various publications and editor of Kauai Backstory, an online literary journal. She has been a part of RYLO since its inception, and loves being involved in the ground breaking business of moving earth.View all posts by Lois Ann Ell →

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