In addition to pink, lisianthus cultivars are available with purple, blue and white flowers.
Prairie gentian, usually marketed as lisianthus, has fleshy gray-green opposite leaves, each with 3-5 conspicuous veins. The leaves are oblong, without hairs, and about 3 in (7.5 cm) in length. In summer the plant sends up erect, 1-3 ft (30-90 cm) tall stalks, each bearing 6-8 flowers, shaped like upturned bells about 2 in (5 cm) across. The five petals are waxy looking and light purple with darker centers. Numerous cultivars and cultivar series with differing flower colors, larger flowers, differing mature heights, and some with double flowers are on the market.
Location Eustoma grandiflorum (formerly called Lisianthus russellianus) is a native American wildflower that grows in the prairies of Texas, New Mexico, Oklahoma, Colorado, Kansas, and Nebraska.
Adapted to growing on the prairies of North America, this gentian prefers a neutral to alkaline soil and fares poorly in acidic soils. Support the stems to keep the flowers from falling over. Deadhead spent blossoms. Prairie gentian has a long tap root and this makes it difficult to transplant successfully. Light: Prairie gentian needs full sun. Moisture: Prairie gentian needs a slightly moist soil, but it must still be well drained. It does not do well in humid or rainy climates. Hardiness: USDA Zones 8-10. Prairie gentian can be grown in cooler climates if given an indoor head start on the season. Propagation: Gentian seeds need light to germinate, so don't bury them; instead, press the seeds lightly into the surface of the soil. Sow the seeds outdoors in autumn or winter for spring germination. Alternatively, you can start them in pots 8-12 weeks before the average last day of spring frost to give them a head start.
The fleshy grey-green leaves create a beautful background for the delicate tulip-shape flowers. Grow lisianthus in containers as annuals if they are not hardy in your area.
Prairie gentian flowers are perfect for cutting. The satiny blossoms will last three weeks or more in a vase of water. In the garden, use these late blooming annuals in beds and borders, but keep them near the front where their delicate beauty won't be hidden by more robust summertime plants. You'll need to support the flowering stalks with little twigs. The flowers will close up on rainy days. Prairie gentian can be used as an indoor, potted flowering plant in a bright, well lit room, and was originally introduced for that purpose before it was marketed as a bedding plant.
Seeds may take a few weeks to germinate and the little seedlings grow quite slowly at first. Pinch stems back a couple times to force branching. Do not over water. Prairie gentian is usually an annual, blooming its first year and then dieing.
Sometimes called Texas bluebell, this gentian should not be confused with Texas blue bonnet (Lupinus texensis), which is a member of the legume family, Fabaceae. Native to the American prairie where natural, lightning-caused fires once swept across the landscape at frequent intervals, prairie gentian has a well developed taproot which stores the carbohydrates needed to recover quickly after the top gets burned to the ground. There are just three species in the genus Eustoma, and they occur in grasslands in North America, Central America and northern South America. Prairie gentian is new to the horticultural trade, having been introduced only in the 1980's.