An update on this story is in Banned Plants. Somewhat to my embarrassment, it appears that Lilium formasanum is on the pest plant list in NZ and banned from sale.
The last of the lilies for the season is flowering now. Lilium formasanum hails, as older readers and plants people will know, from the island of Taiwan, which was formerly known as Formosa. It is another trumpet type of lily. Ours are all seedlings scattered through parts of the garden now and essentially white. Some forms have more of a pink to purple flush or streaking on the backs of the petals. The stems can be tall at up to 1.8m so it is easiest to have them growing amongst other plants which can give some support. I admit our self sown seedlings tend to flop around and need to be leaned up against nearby shrubs where there are some available.
As with lilies in general. L. formasanum prefers full sun but is not fussy about soil types. In fact it is not fussy about much at all and gently seeds down through our open woodland areas, flowering freely in late summer. By open woodland, I mean a high leafy canopy which allows good light levels but no direct sun. Unlike many other bulbs, formasanum does not take long to flower from seed. Where it has seeded down naturally, we think that it flowers two years from seed but according to bulb expert, Terry Hatch, if you gather the seed when it is ripe in autumn and sow it in early spring, you can get it flowering by late summer. That is a quick turnaround though you will only get a single flower, not the cluster in that first year. Its light foliage means that it will die down gracefully in autumn and yes it does have a scent, though only a light one.
First published in the Waikato Times and reprinted here with their permission.