Planting a potted lily outside is generally the best way to ensure the plant’s long-term survival and annual return. Hardy varieties of the Lilium genus are perennial bulbs that thrive when established in garden soil, allowing them to enter a natural dormancy cycle. Moving a potted lily from an indoor environment to the garden requires careful timing and preparation to help the bulb acclimate and store the energy needed for future blooms. Success depends on identifying the type of lily, choosing the right spot, and following precise transplanting steps.
Identifying Your Lily Type
The first step is confirming you have a true lily, which belongs to the genus Lilium. Many plants are commonly called lilies, such as Daylilies (Hemerocallis) and Calla Lilies (Zantedeschia), but these are not true lilies and have different hardiness requirements. True lilies grow from a scaly bulb and have leaves that spiral or whorl around a single, unbranched stem.
Hardy true lilies, suitable for most temperate gardens, include the popular Asiatic, Oriental, and Trumpet hybrids. Asiatic lilies are typically the shortest and earliest to bloom, while Oriental lilies are known for their strong fragrance and larger flowers. These perennial bulbs are adapted to survive winter dormancy outdoors in USDA Hardiness Zones 3 through 9, depending on the specific variety. If your potted plant is a tender variety, like a Peace Lily, it must be treated as a houseplant and cannot survive freezing temperatures outside.
Timing and Preparing the Planting Site
The ideal time to move a potted lily to the ground is either in the early spring, once the soil is workable, or in the late summer and early fall. Fall planting, which should occur about six weeks before the ground freezes, allows the bulb to establish a strong root system before winter dormancy. If you are transplanting a lily that has just finished blooming indoors, you should first “harden off” the plant by gradually exposing it to outdoor conditions over seven to ten days.
Lilies require a site that receives six to eight hours of direct sunlight daily for optimum growth and blooming. In regions with intense summer heat, choosing a location that offers afternoon shade can prevent scorching and prolong flower life. Good drainage is essential, as lily bulbs will quickly rot in soggy soil. You can improve drainage by amending the planting area with organic material like compost or planting the lily in a slightly raised bed. Lilies prefer rich, well-drained soil with a pH that is neutral to slightly acidic, typically between 6.0 and 7.0.
Step-by-Step Transplanting Guide
Begin by preparing a hole two to three times wider than the pot and deep enough to accommodate the bulb’s size. The general rule for planting depth is to set the bulb so the top is covered by soil three times the height of the bulb itself, often six to eight inches deep. This deep planting encourages the development of stem roots, which helps stabilize the tall stalk and keeps the bulb cool.
Carefully slide the lily from its pot, minimizing disturbance to the roots and any existing foliage. Place the bulb, with its roots facing downward, into the prepared hole, ensuring the stem is oriented upright. Incorporate a handful of bone meal or a balanced bulb fertilizer into the soil around the bulb to provide a slow-release source of phosphorus and potassium. Backfill the hole with soil, pressing gently to remove air pockets, and water the newly planted area thoroughly to help the soil settle.
Essential Outdoor Care and Winterizing
After transplanting, the lily needs consistent care to establish itself. Water the plant deeply once or twice a week during dry spells, aiming to keep the soil moist but never saturated to prevent bulb rot. Lilies are heavy feeders, so fertilize them twice during the growing season: once in the early spring as the shoots emerge and again when the flower buds begin to form. Use a balanced fertilizer, such as a 10-10-10 formulation, or a high-potassium liquid feed.
In the fall, after the flowers have faded, resist the urge to cut back the green foliage immediately. The leaves are still performing photosynthesis, storing energy in the bulb for the next season’s bloom. Wait until the foliage has completely yellowed or died back naturally, typically in late fall, before cutting the stem down to about two to three inches above the soil line. For the first winter, especially in colder climates, apply a thick layer of three to six inches of organic mulch, such as straw or shredded leaves, over the planting site. This insulation will protect the newly established bulb from extreme cold and damaging freeze-thaw cycles that can push bulbs out of the ground.