The trumpet flowers attract some pollinators, especially butterflies, but mostly we grow them for their ability to grow 7 or 8 feet tall and add drama to the perennial beds.
Our first one came from Old House Gardens several years ago and it has multiplied many times over the years. Fine Gardening says they commonly multiply by seed.
Another resource says Robert Fortune, the English horticultural botanist visited Taiwan in 1854 and called them Lilium japonicum. Fortune is thought to be the first westerner to ever visit Taiwan collecting plants. In his book, "A Residence Among the Chinese" he says that it is the largest and most lovely lily he had ever seen.
Interestingly, they are considered endangered in Taiwan and they are considered invasives in south Africa where homeowners are asked to remove and discard the bulbs. New Zealand also considers them to be an "unwanted species" and requests that citizens remove them when found.
For the rest of us, they are a celebration of summer heat and being outside in the garden.
If your Formosa lilies form seedpods and you would like to try your hand at planting the seeds rather than increasing your stock by dividing the bulbs, there are easy to follow directions on an east Tennessee garden blog called Fairegarden. Click here to read all about planting them from seed.
Since this post went up, several people have weighed in on the precise identification. Pacific Bulb Society agrees with the bulb seller that it is a Formosa Lily. Horticulturist Russell Studebaker thinks not and his friend Tony Avent of Plant Delights Nursery says it is a member of the Pink Perfection Group.
Trumpet lilies belong to Division 6, Trumpet and Aurelian Hybrids on the classification of lilies. Division 6 includes hybrids of L.leucanthum, L. regale, L. sargentiae and L. sulphureum. Aurelian hybrids are lilies that has Lilium Henryi in their ancestry.
So, I'm sharing a bulb with Studebaker and Avent so they can grown them and make the final determination for themselves.