Oriental Lilies (Lilium orientalis hybrids) are popular garden plants known for their impressive size and intensely sweet fragrance. They naturally increase their stock in a garden setting, a process fundamentally different from seed reproduction. Understanding these methods can help gardeners manage their lily collection.
How Oriental Lilies Naturally Increase Their Stock
Oriental lilies primarily increase their number through asexual reproduction that occurs underground. The mature bulb produces smaller daughter bulbs, called offsets or bulblets, which form around the base of the parent bulb and along the underground stem. These offsets are genetic clones, ensuring the new lily will have the exact same flower color, size, and fragrance as the parent.
This multiplication causes lilies to form tight clumps over time, with new stems emerging close to the original plant. While clumping indicates a healthy, multiplying lily, overcrowding can eventually reduce the vigor and flower size of the entire group. Gardeners typically divide these clumps every three to five years to maintain plant health and encourage robust flowering.
The Difference Between Spreading and Seed Reproduction
Vegetative spreading through offsets is distinct from the plant’s sexual reproduction by seed. Oriental lilies produce seed pods containing viable seeds after the flowers fade. However, planting seeds from hybrid varieties rarely produces a plant identical to the parent due to genetic recombination.
Seeds require specific cold and warm cycles to germinate and take a significant amount of time to develop. A lily grown from seed typically requires three to seven years of growth before it is mature enough to bloom. Since offsets are clones that mature much faster, the vegetative process is the primary method by which lilies multiply in the garden.
Practical Steps for Dividing and Increasing Your Lilies
Division
Active division is the most straightforward method to accelerate the multiplication of Oriental lilies. The best time to divide is in the fall after the foliage has died back, or in the very early spring before new growth begins. Dividing at this time minimizes stress and allows new bulbs to establish roots before the next growing season.
To divide a clump, carefully dig around the cluster, starting a few inches away from the stems to avoid damaging the bulbs. Gently lift the entire clump out of the ground using a garden fork or spade. Remove most of the soil to clearly see the parent bulb and the smaller offsets attached to its base.
Gently pull or twist the bulblets away from the main parent bulb. Ensure each new bulb has a portion of the basal plate and some roots intact, if possible. Replant these separated bulbs immediately at a depth typically three times the height of the bulb. The largest separated bulbs will likely bloom the following season, while smaller offsets may take one to two years to reach flowering size.
Bulb Scaling
A more intensive method for increasing stock is called bulb scaling. This technique uses the lily bulb’s natural regenerative ability by removing individual, fleshy scales from the parent bulb. Carefully snap off four to eight outer scales near the base of a healthy bulb, ensuring a small piece of the basal plate remains attached to each scale.
The scales are then placed in a plastic bag with a slightly moist medium, such as peat moss, vermiculite, or a sand/potting mix, and kept in a warm, dark location. Within two to three months, tiny bulblets will form at the base of the scales. These bulblets, still attached to the original scale, can then be potted up or planted into a nursery bed to grow on for a year or two until they are large enough for the main garden.