Aztec lilies produce seeds and bulblets. Pollinated flowers will set seed. Leave the seed pods on the plant until they split, as the mature seeds are fertile. However, since Aztec lily does not flower every year, the most reliable way to increase the number of plants in your garden is by separating the bulblets that grow from the parent bulb.
Separate the bulblets during autumn when the plant is dormant. Plant them individually in 6-inch flowerpots, or in the ground from 8 to 12 inches apart. Dig a hole about 4 inches deep and place the bulb in it so that the neck is showing above the ground. Aztec lilies do not need a dormant period until they reach maturity at two years of age, according to the Wisconsin Master Gardener Program.
Someone may have given you a lovely Aztec lily as a gift. You can transplant it to your garden during the growing season for your region of the country (see Resources). Choose a sunny area in your garden that has good drainage. You may want to add the lily to a terraced planting or to your rock garden.
Aztec lilies are not frost tolerant. If you live in an area that gets an occasional light frost, protect the bulbs with a layer of mulch. However, if you live in a colder climate, then dig up the bulbs before the first frost, and store them in a dry, frost-free area, such as a heated basement.