The crinum lily -- known scientifically as Crinum asiaticum and also called the swamp lily and the spider lily -- is a perennial plant that features long evergreen leaves arranged in a spiral rosette, with showy, fragrant flowers. Depending on the cultivar, the blooms can be white, pink or even candy-striped. A native of Asia, the crinum lily, which can grow to 6 feet tall and 7 feet wide, thrives in warm-weather locations. You can propagate crinum lily with little difficulty by division.
Put on heavy garden gloves to avoid skin irritation that can result from dividing your crinum lilies.
Dig up the clump of crinum you want to propagate, starting about 1 foot away from the plants and digging down at an angle. Use a sharp, clean knife or strong scissors to separate the small offset bulbs cleanly from the parent bulb. Take care while lifting the bulbs; some can weigh up to 13.6kg. Replant the parent bulb in its original location.
Select a planting site for your offset bulbs in full sun with moist, fertile, well-drained soil with a pH of 6.1 to 7.8. Crinum lilies can grow well in partial shade, but to produce the best blooms, they should get six hours a day of direct sunlight. Space the bulbs of the new crinum lilies at least 36 to 48 inches apart.
Dig a hole 12 inches deep and around twice the size of the bulb for each crinum lily bulb, and loosen the soil at the edges of the hole to promote good root establishment. Plant the bulbs with the tip of the bulb barely protruding from the ground. Tamp soil down firmly to eliminate air pockets, which can harbour diseases that may stunt the plant's growth.
Water thoroughly and apply a 2-inch layer of pine needle or straw mulch around the base of the lilies to conserve moisture, protect the roots and provide a physical barrier against fungal diseases.
Feed your propagated crinum lilies once a month during the growing season using any commercial fertiliser designed to encourage blooming.
Autumn is the best time for dividing crinum. The lilies can be divided every three to five years. It can take a year or two for the offsets to begin flowering. Crinum lilies are very effective planted in the middle of a ground cover, which provides contrast for the crinum's imposing height and brightly coloured flowers.
All parts of the crinum lily are poisonous if ingested. Don't plant it where children or pets may play.