Things You'll Need
Lilies are warm-weather plants that bloom in a wide range of colors and thrive in almost any sunny location. The spider lily is a specific type of lily that features long, thin petals in place of the normally wide growths and grows only in shades of white. Spider lilies look different from standard lilies but still grow from bulbs as standard lilies do. Divide spider lily bulbs to propagate new plants.
Divide spider lilies at the end of their growing season, in late summer and early fall. At this time, there should still be foliage left on the bulbs, but the plant is going dormant and will take little damage from being interrupted. Dig up the bulbs of an established spider lily plant and carefully lift them up out of the soil. Locate the natural divisions in the bulbs, where individual bulbs are marked with a seam. Each side of the seam should be growing individual roots and stems.
Use a knife to slice each bulb at this division, or twist the bulbs with your hands to break them apart. Replant one of the bulbs at the old site, and water it with 2 inches of water to help it re-establish. Always plant bulbs with the stems facing upward and out of the soil.
Prepare a new site for the new spider lily bulbs. Choose a site that gets full sun and good drainage and amend it to a depth of 1 foot with a mixture of half quick-draining soil and half compost. This mixture will give the new spider lily the good drainage and nutrition it requires. Plant the new bulbs 4 inches into the soil, so that the bulb is fully covered and any foliage rises above ground level. Water the new bulb with 2 inches of water.
Put the new spider lily on the same watering schedule as your old spider lilies, and mulch it for the winter with 2 inches of organic mulch. Expect it to bloom and start growing in the spring, when all your other spider lilies wake up.
Divide lilies every three years or so to keep your established plants neat and healthy. If a lily plant stops growing or blooming, it might be crowded and in need of division.
Lilies suffer in cold temperatures and standing water.