Lilies (Lilium) are celebrated for their vibrant, trumpet-shaped flowers and are grown from a specialized underground storage organ known as a bulb. Propagating them vegetatively—creating a new plant from a piece of the parent—is an efficient way to clone desirable specimens. This asexual reproduction ensures the new plant is genetically identical to the source, maintaining the exact flower color and characteristics. Gardeners use these methods to increase their stock or rejuvenate older clumps by stimulating the development of new, independent bulblets.
Choosing the Best Propagation Method
The term “cuttings” in lily propagation refers to two distinct methods: bulb scaling and stem/leaf cuttings. Bulb scaling is the most widely utilized technique because it offers the highest yield, often producing multiple bulblets from a single parent bulb. This method involves separating the individual fleshy scales, each containing the potential for new growth. Scaling allows for rapid multiplication, though the newly formed bulblets typically require two to three years before reaching flowering maturity.
Stem and leaf cuttings are typically faster to initiate growth but generate fewer new plants per attempt. Stem cuttings involve taking small sections of the flowering stalk, often including a leaf axil. Leaf cuttings use the detached leaves themselves. This technique relies on the plant’s ability to form tiny bulblets at the base of the leaf or stem tissue, producing genetically identical clones.
Essential Timing and Preparation
Successful lily propagation depends on timing aligned with the plant’s natural growth cycle. Bulb scaling is best undertaken when the bulb is dormant, typically in late summer or early fall after the foliage has died back. This timing allows the newly separated scales to form protective calluses and develop bulblets before the onset of winter. Stem and leaf cuttings, which utilize green tissue, are taken earlier, usually after the lily has finished flowering in mid-summer while the stem is still firm.
Preparation requires attention to hygiene to prevent fungal or bacterial infection. All cutting tools, such as scalpels or sharp knives, must be sterilized with alcohol or a bleach solution before use. A planting medium that provides excellent aeration and moisture retention, such as coarse sand, vermiculite, or a peat/perlite mix, is necessary. A horticultural fungicide is often applied to the scales to protect the wounded tissue, and rooting hormone encourages faster bulblet formation on both scales and cuttings.
Step-by-Step Propagation Technique
Bulb Scaling Procedure
To begin scaling, carefully excavate the mature, healthy lily bulb, brushing away excess dirt without damaging the basal plate. Gently snap off the outer, fleshy scales by pulling and twisting slightly. Ensure a small portion of the basal plate remains attached to the base of each scale, as this tissue is where new bulblets will form. If you plan to replant the parent bulb, do not remove more than one-third to one-half of its scales.
Once separated, immediately treat the scales by dipping the broken end into a fungicide powder or a rooting hormone containing fungicide. Place the treated scales in a plastic bag with a slightly damp medium, such as vermiculite or peat moss. Ensure the medium is moist but not saturated. Seal the bag, allowing for minimal air exchange, and place it in a dark location at a consistently warm temperature (around 70°F) to stimulate bulblet formation.
Stem/Leaf Cutting Procedure
Propagating with stem or leaf cuttings requires selecting healthy, firm green tissue from the flowering stem. For stem cuttings, cut a section containing a leaf axil—the point where the leaf joins the stem. Alternatively, gently pull off a leaf with a small piece of stem tissue, often called a “heel.” This stem tissue contains the meristematic cells needed to generate a new bulblet.
Dip the base of the cutting, where the bulblet is expected to form, into a rooting hormone. Insert the prepared tissue into the rooting medium, such as moist sand or a sand/peat mixture, burying the heel or basal end one to two inches deep. Position cuttings so the leaf blade remains mostly above the surface, allowing for continued photosynthesis to fuel bulblet development.
Post-Planting Care and Development
After the scales or cuttings are placed into their rooting environment, consistent care is necessary to promote the formation of independent bulblets. For scales in a bag, the warm temperature of approximately 70°F must be maintained for four to eight weeks, depending on the lily species, with periodic checks to ensure the vermiculite remains lightly moist. Bulblets will begin to appear as tiny, pea-sized growths at the base of the scale.
Once bulblets have formed on the scales, they require a period of cold stratification, or vernalization, to break their dormancy and initiate shoot growth. This is achieved by moving the sealed bag into a cool environment, typically a refrigerator set just above freezing, for six to twelve weeks. For stem or leaf cuttings planted in trays, they should be kept in a humid environment away from direct sunlight, and the medium must be kept evenly moist but never waterlogged.
When the bulblets from either method develop small leaves and a root system, they are ready for transplanting. This usually occurs after the cold period for scales or within six to eight weeks for cuttings. The new bulblets should be planted individually into small pots containing standard, well-draining potting soil. Before moving the young lilies to a permanent outdoor location, they should be gradually exposed to outdoor conditions over a week, a process known as hardening off.