5 Common Poisonous Plants in Hawaii

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Looks can be deceiving. What appears to be green and lush can actually be poisonous. We’re talking about plants in Hawaii. Even those that look exotic—they practically lure you in—can actually be harmful even with a single touch.

Just as weeds crop up in unexpected places, poisonous plants can also take root on commercial properties that are not carefully maintained. This becomes a safety issue for visitors, staff and passersby on your property.

Identifying common poisonous plants is important so you can avoid making contact with these species and have them removed by a properly trained landscape professional, if necessary. Here’s your “hit list” of five common poisonous plants on Kauai to avoid.

Crown of Thorns

Poisonous plants in Hawaii: Euphorbia 'Crown of Thorns'

According to legend, this euphorbia is the plant that the Romans used to make a mock crown that was placed on Christ’s head during the crucifixion. The prickly plant does not welcome picking!

And you won’t get poisoned by its thorns: Actually, the plant’s milky sap contains the highest concentration of poison and skin contact with it will result in skin rashes and blisters.

The key to managing crown of thorns is to wear gloves and avoid contact with the poisonous secretion.

Desert Rose

Desert rose (Adenium obesum)Adenium obesum contains cardiac glysocides that can actually disrupt the heart. Fun fact: those toxins are actually used in Africa as arrow poison. (Well, maybe not so fun for the target.)

This desert rose is not so sweet. You’ll recognize it by its colorful flowers, and they are sometimes grown in pots and used for bonsai.


Tonga Tabu

Sea mango, one of the common poisonous plants in HawaiiAlso known as Sea Mango, Cerberah manghas thrives in seaside environments without watering, which is why you’ll find this plan on Kauai.

The medium sized tree has an attractive profile, with large green foliage and fragrant white flowers. These trees are used in the landscape, but it’s important to know that the tree produces a poisonous sap, and the flowers seeds are poisonous.



Araceae family

Xanthosoma sagittifoliumThis attractive, flowering plant is known for its leaf-like spathe and spadix (column of flowers)—as with the wild calla.

There is a full range of tropical plants in the araceae family, and they can be highly poisonous because they contain oxalis crystals that constrict breathing if swallowed.



Wedelia is one of the poisonous plants in Hawaii that thrives in salty coastal soil.This invasive species goes by the botanical name Sphagneticola trilobata and can fill in quickly on a Kauai commercial property.

The low-growing plant seldom reaches more than 1 foot tall, and its fleshy leaves have a slightly hairy finish. It produces bright yellow flowers year-round, and small cylindrical seeds.

Because wedelia tolerates salty soils and love coastal environments, you’ll find it trailing over rocks and sand. Touching wedelia can cause skin irritation.  

Look Out For Poisonous Plants In Hawaii

Why is knowing what plants are poisonous on your Kauai resort property so important? Because you are ultimately responsible for the safety of those who visit your property.

Worried that you’ve got one of these poisonous plant suspects in your landscape? Call us any time at 808-335-5887, or fill out this simple contact form and we’ll get in touch with you.

At No Ka Oi, our experienced landscape maintenance team is a knowledgeable set of eyes and ears on your property. We’re constantly keeping an eye out for plants that could pose a risk so we can properly warn our commercial clients and remove the plants, if necessary.


Image credits: Desert Rose, Tonga Tabu, Araceae, Wedelia


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