Crinum americanum is commonly known as string lily, southern swamp lily or Florida crinum. It is native to the swamps, marshes and river banks of the southeastern United States. A common plant in many old Southern gardens, it is considered a good "pass-along" plant, because it is easy to give friends offsets or seeds for their own gardens.
The showy flowers of Crinum americanum bloom from May to November on one to three-feet-tall stalks. The flowers resemble a star with six narrow petals and sepals. They are white with red stamens. The flowers may be tinged with pink.
The strap-like leaves are bright green with a leathery texture. They grow one to four feet long and form a rosette.
Crinum americanum grows in Zones 7 to 11. It may die back to the ground during winter in Zones 7 and 8, but will return in the spring. It grows best in partial shade, but will grow in full sun. It will grow in any type of soil and is moderately drought tolerant.
Crinum americanum will also grow in wet areas, such as along the edge of water or in low-lying boggy places. It is a good plant for coastal gardens, because it is tolerant of salt spray.
Crinum americanum is a slow-growing, long-lived plant. It gradually spreads by offsets from the mother plant. Established plants do not like to be disturbed, but new plants may be started from offsets or by seeds.
Pests and Diseases
Grasshoppers, caterpillars and other chewing insects can damage the leaves of crinum americanum. The insects can be removed by hand or sprayed with an insecticide approved for Crinums at the rate recommended by the manufacturer.
Fungal leaf spots may disfigure the leaves, although the fungus will not kill the plant. Leaf spots can be treated with a fungicide approved for Crinums following the manufacturer's instructions.
Crinum americanum can be grown in a perennial bed, a tropical garden, or near a water feature. It also makes an imposing specimen plant. It can be grown as a houseplant in a large container in a bright room. It prefers a cool nighttime temperature--about 55 degrees.
All parts of Crinum americanum are poisonous and can cause stomach irritation if eaten. The sap can cause skin irritation.