Plant purple stargazer lilies in a sunny or partially shady spot in well-drained soil. Choose a location where water doesn't collect after it rains. Amend clay or sandy soil with 4 inches of compost mixed into the top 6 inches of soil.
Plant purple stargazer lilies eight to 12 inches apart. Place small lily bulbs 2 to 4 inches deep and larger bulbs 4 to 6 inches deep.
Water the top 6 inches of the lily bed after planting and keep the soil moist at all times.
Fertilize stargazer lilies as soon as shoots appear and repeat the application once a month through the growing season. Use 4-8-4 fertilizer at the rate suggested on the label.
Spread 2 inches of mulch over the soil around the purple stargazer lily to keep the roots cool and to retain soil moisture.
Deadhead the stargazer lily when flowers fade by snapping them from the stem. Allow the foliage and stem to remain to continue to feed the bulb.
Cut the purple stargazer lily's stems to the soil when the plant turns brown. Add 2 more inches of mulch to protect the bulb through the winter. Pull back the mulch in spring.