The Formosa lily loves the heat and begins producing its huge fragrant blossoms in mid-summer
Formosa lily is one of the tallest of all the lilies, easily reaching 6-7 ft (2 m) in height before blooming in late summer in the South or autumn up north. In much of the south, this tall beauty is called August lily. Formosa lily sends up 2-3 stems from a bulb about an inch (2.5 cm) in diameter. The bulbs themselves are stoloniferous, spreading new plants out from the original. The stems are clothed, bottle brush-like, with numerous dark green linear leaves, each 3-8 in (7-20 cm) long. At the top of the stem, and causing it to be top-heavy to the point of falling over, stands one, two, or a cluster (umbel) of as many as ten, trumpet shaped white flowers, each 5-8 in (12-20 cm) long. The flowers gaze outward and (like all lilies) have six tepals (three petals and three similar looking sepals). The fragrant flowers, with their reflexed tepals, often flushed with purple, last for several days and each ultimately gives rise to a 3-celled capsule, 3-4 in (7-9 cm) long, with numerous little flat seeds packed two rows per cell. The brown, papery seed capsule is itself ornamental and looks good in the fall garden or in a dried arrangement.
Lilium formosanum var. pricei gets only 18-24 in (45-60 cm) tall and has flowers flushed more deeply with purple.
Location Lilium formosanum is native to the island of Taiwan (formerly called Formosa). It supposedly was first found growing on Mt. Morrison on that politically contested island.
Jack's Formosa lilies are planted among and supported by blue salvias, butterfly ginger and other tall perennials.
Formosa lily is, unfortunately, susceptible to lily mosaic virus which causes yellow splotches on the leaves and can kill the plant within a year. The virus is spread between plants by aphids, and there is no known cure. If yours die suddenly, get new bulbs from a clean source and replant in a different area. Light: August lily does best in full sun. Moisture: August, or Formosa lily likes a moist, acidic soil. Hardiness: USDA Zones 5-9. Although they survive and bloom in zones 5 and 6, Formosa lilies there may not have a long enough growing season to replenish their bulbs for the following year. Thus they usually survive only a couple years in the north. Not a problem! Get more bulbs and treat them as biennials. Most lilies, including Formosa lily, need a cool dormant period for the bulbs to "rest", and will not survive in zones 9 and 10 unless dug up and refrigerated for a few weeks during what passes for winter. Propagation: After the stems have died back in winter, lift and carefully divide the bulbs by hand. In the South, you can usually get 2-3 new bulbs from the original each year. Plant bulbs at a depth 2-3 times their height. Sow seeds shallowly as soon as ripe.
One of Steve's rebar crosses supports a huge Formosa lily in his garden. As a bonus, if something dies you'll have a convenient place to put it.
Elegant August lilies are a beautiful sight in late summer when it's so hot you don't even want to go outside during the middle of the day. These big white beauties bloom right through the scorchers and even smell sweet while they do it! I grow August lilies with several kinds of small palms in my "spikey" garden. With their bristle-like linear leaves all along their tall stems, they fit right in. Plant some August lilies along a fence where you can tie them up when they start to fall over, which they surely will. I prop up unruly lilies and other plants that get too tall for their own good with crosses I make by welding a 2 ft (60 cm) length of rebar to a 3-6 ft (1-2 m) length of rebar. I use a vise to bend the ends of the horizontal piece inward a little to help keep the plant stems under control, and then just stick the shank of the cross in the ground. The crosses quickly become almost invisible within the plant's foliage.
Fragrant Formosa lily flowers last for days in a vase of water, and buds that aren't quite open will continue to open as though they were still in the garden. Don't cut more of the stem then you need, because the green stem and its leaves are producing food for storage in the bulb for next year's flowers. And don't cut the stems down in autumn until they have turned brown.
The similar Philippine lily (L. philippinense) is sometimes confused with Formosa lily, but it is shorter, only to 3 ft (1 m), and has slightly smaller flowers. Philippine lily is sometimes found growing wild in Florida where it has escaped cultivation.
The true lilies, genus Lilium, are perennial (pun intended) garden favorites with more than 100 natural species and thousands of hybrids and cultivars to choose from. Lily lovers classify their proteges into nine divisions based on floral characteristics and parental histories. There are dozens of lily societies for those who are smitten; start with the North American Lily Society.