In April, 2018, I visited the Foster Botanical Garden in Honolulu and was delighted to see a double coconut, Lodoicea maldivica, (palm family Aracaceae) growing there. The double coconut, also called the Seychelles coconut, sea coconut, and coco de mer, has the largest seed in the world. It is endemic to two islands Seychelles, small islands in the Indian Ocean. At the time, the Foster Garden was proudly displaying seeds their double coconut had produced.The plants are rare and they are dioecious so a "male" and "female" plant are needed for reproduction.The Seychelles is trying to preserve and increase the wild populations so is not sharing seeds. To pollinate their female palm, Hawaiian botanists brought pollen from Singapore, where there is a male plant. (Blog posts from that visit the plant; getting the seeds. )
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Seed of double coconut, Lodoicea maldivica,
largest seed in the world, Foster Garden 2018
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Flying the pollen from Singapore to Honolulu in 2011 produced seven seeds. It took 6 years for them to mature on the mother palm. Then, they were planted and everyone waited. Double coconuts send down a massive root, and it is usually more than a year before the first leaf appears.The photo below shows one of the five that had germinated and produced a leaf in 2018. The largest first leaf in the world.
I returned to Foster Garden in fall of 2025 eager to see what the plants looked like. They had grown toa be taller than their protective fence:
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| Double coconut, Lodoicea maldivica, Honolulu 2025 |
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Another of the young double coconuts,
Lodoicea maldivica, Honolulu 2025 |
Looking at the big palm, their mother, they have a long way to go.
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mature double coconut Lodoicea maldivica
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But they are much taller than I am. A selfie with me for scale to show how big the young plants are at 7 years old. (I am 5'2", the photo may tilt up slightly).
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Selfie to show you how big and tall the young
plants are after 7 years |
The leaves are massive too. They can be 7-10 meters long, 4.5 m wide and on a 4 m. leaf stem (petiole) according to Wikipedia, confirmed by the leader of the tour I took at Foster Garden. Those numbers, for those of us not fluent in the metric system are 21-30 feet long, 13 1/2 feet wide, on a 12-foot leaf stem. Important to dodge them as they fall in a strong wind! They must also be hard work to sweep up (none were on the ground at Foster Garden). I calculate one medium double coconut leaf equals 2,321 of the maple leaves I recently raked up off the paths in my backyard. (Not considering the leaf stem or whether the double coconut is thicker than the maple leaves, which it is.) There are plants with bigger leaves, but not very many.
The leaves do not look that impressive up in the air because there is nothing up there for scale.
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| Really big leaves on double coconut |
Oh, but what is this? I saw seeds developing on the double coconut. This plant is female, so to have seeds it has to have gotten pollen from another mature double coconut. In 2011 the nearest male plant was in Singapore. Did they do that again?
developing seeds on double coconut
They look big but when mature will be 20" long and
up to 40 pounds
No, my tour guide at Foster explained, they had not gone to Singapore. Some young double coconuts have been growing in the Ho'omaluhia Botanical Garden (
link) in eastern Oahu. One of them flowered for the first time and turned out to be male. So in 2022 botanists carried pollen to hand-pollinate the plant at Foster. The seeds are developing but they take 6-7 years to mature. And another 1-2 years to send up their first leaf after they are planted. From germination, they will take 20 years or more to reach maturity and flower. You need patience to work with double coconuts. But a second group of Hawaiian-produced double coconut seeds is a very hopeful event.
This is a very rare plant. The female and male on Oahu are the only mature ones in the United States. Double coconuts germinate in Florida but the plants are very frost-sensitive and die in Florida's occasional frosts. Although not common, frosts in Florida occur more often than the 20 or 25 years that double coconuts need to reach flowering size. The reports of the seeds in beach drift in Texas are doubtful: I can find no report of them growing in a garden anywhere along the Gulf of Mexico or tropical Atlantic shores. And the huge seeds are quite valuable, whether alive or dead; no one would let them just drop into the ocean. In their native Seychelles, in the Indian Ocean, both the trees and the seeds are strongly protected. There are a few gardens across the tropics where they are reportedly growing, in Africa and Australia, as well as Singapore and Honolulu, probably a few others. The success in Hawaii will very slowly build a protected population of double coconuts that will help preserve this remarkable species.
Go see a double coconut palm if you get a chance.
References
Missouri Plant Finder.
Lodoicea maldivica,
link
Zimmerman, K. 2022.
Lodoicea maldivica, Double Coconut, in Cultivation in Hawaii. Plantspotter69.
link Good video (Accessed 11/29/25)
For those who don't read the internet or prefer books, I gathered posts together into books, for example:
Kathy Keeler.
Curious Stories of Familiar Plants from Around the World available from Amazon
link
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