Lilies (Lilium) are perennial plants well-suited for outdoor garden settings across many climate zones. These true lilies, distinct from daylilies (Hemerocallis), grow from bulbs and are highly valued for their stature and spectacular, diverse flower forms. With hundreds of varieties available, they provide a reliable, returning display of color and often fragrance throughout the summer. Successful outdoor cultivation relies on selecting the appropriate variety and ensuring the correct environmental conditions are met.
Selecting the Right Variety and Location
Choosing the right lily begins with understanding the local climate and the plant’s needs. Lilies generally flourish in full sun (six or more hours of direct sunlight daily), though they appreciate having their roots shaded and cooled by surrounding low-growing plants. The soil must be well-draining, as the bulb is prone to rot if kept in standing water. A soil pH that is neutral to slightly acidic (6.0 to 7.0) is suitable for most varieties.
Different lily types have distinct preferences and hardiness levels. Asiatic lilies are the hardiest and most tolerant of varied soil conditions, making them excellent choices for colder climates and alkaline soils. Oriental lilies, known for their large, intensely fragrant flowers, generally prefer slightly acidic soil and may benefit from afternoon shade in regions with intense summer heat. Trumpet and Orienpet hybrids (Lilium OT hybrids) are robust, tall, and often fragrant, extending the bloom season.
Proper Planting Techniques and Timing
The optimal time for planting lily bulbs is in the fall, approximately six weeks before the ground is expected to freeze. This allows the bulb to establish roots before winter dormancy. Planting in the spring is also possible, though fall planting often results in better first-year blooms. Planting depth is a factor for stability and stem-root development.
A general rule is to plant the bulb at a depth two to three times its height, usually 6 to 8 inches deep for most large varieties. This deep placement is necessary because many lilies are “stem-rooting,” producing additional roots along the underground portion of the stem above the bulb. Place the bulb with the pointed growing tip facing upward and space bulbs 8 to 18 inches apart to ensure adequate air circulation. After placing the bulb, gently backfill the hole, remove any air pockets by pressing the soil lightly, and water thoroughly to settle the soil.
Ongoing Seasonal Care and Maintenance
Once planted, lilies require specific care throughout their active growth period to ensure robust flowering. Watering should be deep and infrequent, keeping the soil consistently moist but never soggy. This is particularly important during dry spells when rainfall is less than one inch per week. Maintaining a layer of mulch helps keep the soil cool and conserves moisture.
Lilies benefit from a consistent feeding schedule. Apply a balanced granular fertilizer, such as a 10-10-10 or a formulation with a lower nitrogen content, in early spring as the shoots emerge. A second feeding with a higher phosphorus and potassium blend can be applied in mid-summer when the flowers are opening to help the bulb store energy for the next season. Taller varieties, such as Trumpet and Oriental lilies, may require staking to prevent heavy flower heads from bending or breaking the stem in windy conditions.
Preparing Lilies for Winter Dormancy
Proper preparation for winter ensures the lily bulb survives the cold and returns the following year. The foliage must remain after flowering and only be cut back once it has completely turned yellow or brown in the autumn. This yellowing signals that the plant has reabsorbed energy from the leaves back into the bulb for dormancy. Cutting the stem back prematurely starves the bulb and can result in reduced or absent blooms the next season.
Once the foliage is spent, cut the stems back to a few inches above the ground to mark the planting location and reduce potential entry points for disease. In colder climates, or where freeze-thaw cycles are common, apply a thick layer of organic mulch (such as straw or shredded leaves) over the planting area. This 4- to 6-inch layer of insulation helps maintain a consistent soil temperature, preventing damage from soil heaving.