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  • Writer's pictureAmy Christmas

A Hawaii Artist discovers beauty and more in Island Sourced Materials!

Ironwood, Sheoak-Casuarina equisetifolia

-4 Things you may not know about this Kauai plant

Forest & Kim Starr, Starr Environmental

1. What is it? The Ironwood is a common site in the Hawaiian Islands, especially near the beach. It is often thought to be a type of pine tree, but actually is a member of the Sheoak family. Its leaves look like pine needles to the casual observer, but if you look closely, although they appear to be long needles, they are actually segmented whereas pines needles are smooth. The needle-like leaves are in whorls of 6-8 and vary in length from 9-15”. The way the branches droop look similar to a horsetail which is another common name for this plant along with whistling tree for the sound it makes when any breeze blows through it. The Sheoak is an evergreen but does shed its leaves regularly making it quite messy. It can grow up to 100’ in Hawaii. It has the ability to fix nitrogen, grows rapidly, and has an aggressive root system making it a good aid in controlling soil erosion. Unfortunately, the con of the carpet created by constant shedding and persistent rooting habit makes it very hard for any plant to grow under it. Ironwood shares the ability to fix nitrogen like the Legume family, and grows rapidly. It’s bark is greyish brown and gets more shaggy as it ages. It’s male flowers look similar to pine tree catkins and the female flower is reddish but rather small and inconspicuous. The female flowers are followed by a warty cone-like fruit which turns brown and releases a small tan winged seed. The Ironwood can handle a lot of pruning, making a beautiful hedge, will tolerate poor soil, temperatures as low as 42 degrees F, and salt. It flowers and fruits all year, has naturalized in many regions, and is considered to be invasive in Hawaii, South Florida, the Caribbean, India, and Brazil.

2. Where did it come from? The Ironwood is native to a fairly large region from Southeast Asia, Northern Australia, and the Pacific Islands. It is believed to have been one of the plants introduced by King Kalakaua in the late 1800’s, and 4 acres were planted near Lihue by Grove Farm in 1874. There were more than 70,000 starts planted in the forestry preserves on the 4 main Hawaiian islands with as many as 38,000 being planted on Kauai from 1928-1940. The main use of the tree is as a windbreak, a control for dune stabilization, and for reforestation. It’s wood is very hard and heavy making it highly regarded as firewood and charcoal. It doesn't cut easily but has also been used in ship masts, boat oars, posts, and tool handles and shingles. In India, it’s wood fiber is used in the production of paper pulp. Root extracts have been used in treatment of dysentery, along with other stomach ailments. Another interesting use is as a bonsai plant with especially popular in South-east Asia and the Caribbean.

3. When is the best time for collecting?

The cones are collected as they brown and fall to the ground. We can always find them so we gather them as needed. They store well in open-air containers indefinitely.

4. How are the collected plant parts used?

In my research, I saw the cones used in potpourri and sliced and used in jewelry. We use the cones to depict different things on our ornaments. They have been made to look like pineapples, a coconut bra for our hula angel, a horse for our paniolo, and most currently as a Kapa pounder for our traditional Hawaiian mother angel.

*Amy is a University of Hawaii Certified Master Gardener Emeritus, has a Bachelor of Science-Landscape Horticulture degree from Ohio State, has been a volunteer tour guide at NTBG, and is a self-proclaimed "plant nut"! She and her husband Ron have been making and selling their baskets for more than 20 years.



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