Tuesday, May 19, 2009

Vernicia fordii, the Tungoil Tree

We're doing a bit of spring planting this week in the Asian Collections; among other things I planted this interesting arboreal member of the Euphorbiaceae. I'm not very optimistic about its chances of surviving even a benign Zone 7 winter. Initial forays into the literature suggest that it's hardy to about USDA Zone 9. I hope to be pleasantly surprised. {15 minute hiatus for more research!} Actually, I just looked in Krussmann and he has it (in its old genus Aleurites) as USDA Zone 6 !?!? That feels like a mistake but hey it looks great with the sun shining through it!

For many years the tree has been cultivated in China for the oil extracted from its nuts. In modern times it has been exported to other areas around the world with suitable climates (not Zone 6, more likely Zone 9 and up). It is actually a listed invasive plant in Florida so maybe we don't want ours to survive! But seriously, if it manages to survive the winters here, its vigor would very likely be reduced to the point where it would not be a problem.

Though removed from the genus Aleurites, it retains a close kinship to the Kikui nut tree, Aleurites moluccanus, which is itself an interesting plant and the state tree of Hawaii. As I write this I sit more or less underneat a Kukui nut necklace I brouch back from Hawaii: the large wooden seeds are threaded onto a string. They are pretty hefty nuts; 18 of them make a good sized string.

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