Stargazer lilies produce upward-facing flowers with a sweet fragrance that fills summer gardens. These oriental hybrid lilies grow well in most temperate climates and come back each spring from their underground bulbs.
Stargazer lilies grow in USDA Zones 4 to 9. They prefer full sun, moist but well-drained soil, and a spot where their roots stay cool. The flowers bloom in mid to late summer on stalks that reach 3 to 4 feet tall. Plant the bulbs 6 inches deep in slightly acidic soil that has good drainage.
Origin of the Stargazer lily
Leslie Woodriff bred the first Stargazer lily in the 1970s. He wanted an oriental lily with upward-facing flowers instead of the downward-facing or outward-facing blooms common in most oriental types. Before Stargazer, oriental lilies (Lilium spp.) typically nodded toward the ground or faced sideways. Woodriff likely crossed Lilium auratum with Lilium speciosum to create this new form. Stargazer became one of the most widely grown lily cultivars in the world and set the standard for upward-facing oriental hybrids. The North American Lily Society classifies Stargazer in Division 7, which includes oriental hybrids and their crosses.
Stargazer lilies are perennial plants that return from their bulbs each spring. With proper care, the bulbs can produce flowers for many years. The plants adapt easily to different garden settings and need less fussing than many other ornamentals once established.
Growing zones and climate
Stargazer lilies grow best in USDA Zones 4 through 9. They tolerate winter cold down to about -30°F (-34°C) but need some freezing weather to perform well. Areas that never drop below 32°F (0°C) in winter do not provide enough dormancy for the bulbs. The plants also struggle in regions where winter temperatures stay below -30°F for extended periods. Most temperate climates with distinct seasons fall within this range. The bulbs go dormant in fall, survive frozen ground through winter, and push up new shoots when soil warms in spring.
Summers in Zones 4 to 9 provide enough warmth for Stargazer lilies to bloom without stressing the plants. Hot, humid climates can challenge the plants if drainage is poor or if fungal diseases become active. Good air circulation and well-drained soil become even more important in warmer zones.
Soil and planting depth
Plant Stargazer lily bulbs in slightly acidic soil with a pH between 6.0 and 6.5. The bulbs tolerate neutral soil but perform better when acidity is on the lower end of that range. Add sulfur or compost to acidify soil that tests above 7.0. Soil drainage matters more than pH. Stargazer bulbs rot quickly in waterlogged ground. Loose, crumbly soil that drains within a few hours after heavy rain works best. Sandy loam or amended clay both work if water does not pool on the surface.
Bury each bulb about 6 inches deep. A common guideline is to plant bulbs at a depth three times their height. Stargazer bulbs are usually 2 to 3 inches tall, so 6 to 8 inches deep is about right. Deeper planting protects the bulbs from frost heave in cold zones and keeps them cooler in hot zones. Space bulbs 12 to 18 inches apart to allow room for the mature plants.
Full sun produces the strongest stems and most blooms. Stargazer lilies need at least 6 to 8 hours of direct sunlight each day. They tolerate light afternoon shade in hot climates, but too much shade weakens the stems and reduces flower count. Plant them where morning sun can dry dew from the leaves, which helps prevent fungal problems.
When to plant
Plant Stargazer lily bulbs in fall before the ground freezes. September through November works in most zones. Fall planting gives the bulbs time to develop roots before winter dormancy. The roots grow slowly through late fall and early winter, then surge in early spring when soil warms. Potted starter plants are usually available in spring and can go into the ground after the last frost date. Spring-planted potted lilies often bloom the same year if planted early enough.
Add 2 to 3 inches of organic mulch over newly planted bulbs. Shredded leaves, straw, or composted wood chips all work. Mulch moderates soil temperature, keeps the ground from freezing too hard in cold zones, and slows early growth if a late frost threatens. Pull back some of the mulch in early spring once shoots appear, but leave a thin layer to conserve moisture and suppress weeds.
Watering and ongoing care
Keep the soil evenly moist during the growing season. Stargazer lilies need consistent moisture from the time shoots emerge in spring until foliage dies back in fall. Dry soil slows growth and reduces flower size. Water deeply once or twice a week if rainfall is scarce. The top 2 inches of soil can dry between waterings, but do not let the root zone become bone dry. Drip irrigation or soaker hoses work well because they keep foliage dry and deliver water directly to the root zone.
Reduce watering after flowers fade and foliage begins to yellow. The bulbs enter dormancy as summer ends. Too much water during dormancy can cause rot. Let the foliage turn completely yellow before cutting it back. The leaves photosynthesize and send energy back to the bulb, which helps the plant return stronger the next year.
Feed Stargazer lilies once in early spring when shoots are 4 to 6 inches tall. A balanced granular fertilizer with equal parts nitrogen, phosphorus, and potassium works well. Scatter the granules around the base of each plant and water them in. Avoid high-nitrogen fertilizers, which push leafy growth at the expense of flowers. A second light feeding right after blooming can help the bulbs store energy for next year.
Managing deer and small mammals
Deer eat Stargazer lilies. They chew off flower buds, strip foliage, and sometimes dig up bulbs. An 8-foot fence is the most reliable barrier, but many gardeners cannot or will not install one. Motion-activated lights or sprinklers can startle deer and train them to avoid the area. Reapply deterrents after rain. Egg-based sprays work if applied every few weeks. Mix one beaten egg with five parts water and spray the foliage and ground around the plants. The smell repels deer but fades quickly.
Planting deer-resistant companions around Stargazer lilies sometimes helps. Lavender, yarrow, and salvia have strong scents that deer avoid. Surrounding lilies with these plants can reduce browse pressure. Netting or wire cages around individual plants also work, but they are less attractive in a garden setting.
Voles, chipmunks, and other small mammals dig up and eat lily bulbs. Hardware cloth buried 12 inches deep around the planting area blocks tunneling animals. Mixing sharp gravel into the soil around each bulb can discourage digging. Castor oil repellents upset the digestive systems of burrowing animals. Mix three parts castor oil with one part dish soap, dilute with water, and pour into tunnel entrances. Reapply every two weeks. Some gardeners plant extra bulbs to compensate for losses, which is easier than constantly battling small mammals.
Controlling aphids
Aphids cluster on Stargazer lily buds and stems. They suck sap from the plant and can spread viral diseases. Check the undersides of leaves and the tips of flower buds for small green, yellow, or black insects. A strong spray of water from a hose knocks most aphids off the plant. Hold a bucket under the foliage to catch dislodged aphids, then dump the water away from the garden. Repeat every few days until the population drops.
A spray of water mixed with a small amount of rubbing alcohol or insecticidal soap can kill aphids on contact. Mix one tablespoon of rubbing alcohol or insecticidal soap per quart of water. Spray the stems, leaf undersides, and buds. Avoid spraying in full sun or on very hot days, which can burn foliage. Reapply weekly if aphids return.
Releasing ladybugs into the garden provides natural control. Ladybugs eat aphids and do not harm plants. Purchase them from garden centers or online suppliers. Release them in the evening when temperatures are cooler, so they settle in rather than flying away immediately.
Dividing bulbs
Divide Stargazer lily bulbs every three to four years. Crowded bulbs produce fewer flowers. Division also creates new plants for other parts of the garden. Dig up the bulbs in early spring just as shoots begin to emerge. Lift the entire clump with a spade, taking care not to slice through the bulbs. Shake off loose soil so the bulbs are visible.
Pull apart bulbs that separate easily by hand. If they resist, use a sharp knife to cut through the basal plate where roots attach. Each division needs at least one growing point and a portion of the basal plate with roots attached. Replant divisions immediately at the same depth they were growing before. Water them in well. Divided bulbs may produce smaller flowers the first year but recover quickly.
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