Propagating true lilies (Lilium species) allows gardeners to multiply their favorite varieties. Lilies naturally produce clones, and propagation accelerates this process. The best time to propagate is when the plant is dormant, typically in early fall after the foliage dies back or in very early spring before new growth emerges. This timing ensures the parent plant has stored maximum energy and minimizes stress.
Propagating Lilies by Separation
The simplest method for creating new lily plants is by separating the natural offsets that form around a mature bulb. Lilies can become overcrowded after three to five years, signaling that the clump is ready to be lifted and divided. To begin, gently lift the entire clump using a garden fork, taking care not to damage the underlying root system.
Once the clump is lifted, the larger bulbs, called offsets, can be separated from the main mother bulb. Offsets are fully formed, smaller bulbs that developed next to the original. They will typically produce flowers the following season. Gently twist or pull these bulbs apart and replant them promptly into their new location.
Many lily varieties also produce smaller reproductive growths called bulblets and bulbils. Bulblets are tiny, underground bulbs that form along the stem between the main bulb and the soil surface. Bulbils are small, dark, pea-sized bulbs that some species, such as Tiger Lilies, produce above ground in the leaf axils. Both can be harvested from the stem and planted separately to grow new, genetically identical plants.
Propagating Lilies Using Bulb Scaling
Bulb scaling is a high-yield technique that produces numerous new plants from a single parent bulb. This method utilizes the fleshy, modified leaves of the lily bulb, as each scale contains the potential to regenerate a new plant. Start by gently digging up a healthy, mature lily bulb, preferably in late summer or early fall.
To harvest the scales, gently twist or peel the outer, healthy scales away from the basal plate. Ensure a small piece of the basal tissue remains attached to each scale. It is recommended to only remove the outer one or two layers of scales so the remaining parent bulb can be replanted and survive.
The harvested scales must be prepared to prevent fungal rot during incubation. Treat the scales with a fungicide or a light dusting of sulfur powder before placing them in a sterile, moist medium. A slightly damp mix of vermiculite, or a peat moss and perlite blend, provides a clean, moisture-retentive environment.
Place the prepared scales and medium into a plastic bag, ensuring the scales are not directly touching the plastic to avoid localized condensation. Seal the bag and place it in a dark location at a warm room temperature, ideally around 70°F (21°C). This warm incubation phase lasts approximately four to six weeks and encourages the scales to form tiny bulbils at their base.
Following the warm period, the bulbils must undergo a cold treatment, known as vernalization, to break dormancy and stimulate shoot growth. Move the sealed bag into a cold environment, such as a refrigerator, for six to twelve weeks at a temperature just above freezing. This mimics the natural winter cycle and prepares the bulbils for active growth.
Nurturing and Growing New Lily Plantlets
Once the bulbils have developed roots and completed their cold period, they are ready for transition into a growing medium. Pot the small bulbils into a well-draining soil mix. A blend formulated for bulbs, or a standard potting mix amended with perlite or grit, will prevent waterlogging and reduce the risk of rot.
Plant the small bulbils approximately a half-inch deep in starter pots, ensuring they are spaced far enough apart to allow for initial growth. Place the pots in a location that receives bright, indirect light or partial shade, as the tender new foliage can be scorched by intense direct sun. Water the pots consistently, but allow the top layer of soil to dry slightly between waterings.
During the first growing season, apply a dilute, balanced liquid fertilizer every few weeks to support bulb and foliage development. The young plants should be protected from harsh winter conditions for the first year. Depending on the species and method, it can take two to four years for propagated lilies to reach a mature size capable of flowering.
The largest offsets from division may bloom in the first year. However, the smaller bulbils from scaling or stem growth will require more time to build up sufficient size and energy reserves. Once the young lilies have established a robust root system and the risk of frost has passed, they can be carefully transplanted into their final garden location.