GBG Note No. 22

Many cultivars of Asiatic hybrid lilies have been tested over the years at the Georgeson Botanical Garden. This group of lilies is the most reliably hardy lily in Interior Alaska and provides brilliant color displays in late July and August. Homeowners and commercial growers can easily increase their quantity of lilies by vegetatively propagating the bulbs.

Asiatic hybrid lilies have scaly bulbs. These bulbs are not enclosed in a papery covering such as an onion or tulip. Instead, the bulbs are composed of a series of loose, fleshy scales. Anytime after flowering and throughout winter, these scales can be harvested and propagated to produce tiny bulblets that will flower in two or three years. The following method is an easy and quick way to get plenty of bulbs from one large bulb.

Remove the parent bulb from its packing material (wood shavings, sawdust, etc.). Wash the bulb in clean water to remove this material. Peel off no more than 25 percent of the spoon-shaped, fleshy scales. Discard any that appear diseased or broken.

Fill two-thirds of a new plastic bag (Ziploc® works well) with vermiculite that is available at garden centers and commercial greenhouses. Moisten the vermiculite until it is uniformly wet but with no standing water.

Drop the scales into the bag and mix into the vermiculite. Make sure each scale is completely surrounded by moist vermiculite. A quart-sized bag can hold about a dozen scales. Some commercial growers dust the scales with a fungicide prior to inserting into the bag, but I have never found that necessary. Close the bag.

Pot up the parent bulb. Place the container in a cool environment (38 to 45°F) until growth begins. When young shoots appear, bring the container into a warm room or greenhouse to bloom. With care, this parent bulb can be planted outdoors in spring. If flowering occurs indoors, keep growing the plant after flowering, and don't remove any foliage. Plant the bulb and attached stem in the garden in June.

Set the bag full of scales and vermiculite in a warm room (approximately 70°F). Avoid cold windowsills or hot south-facing windows. Check the bag at least once a week to make sure vermiculite stays moist. In about three weeks, begin checking for small bulblets forming at the base of each scale. Keep the scales in the vermiculite until you notice some roots and green shoots developing from the bulblets.

Carefully remove the bulblets from the scale, and plant them in flats or shallow containers using sterile potting mix. Water to keep the soil moist.

After the bulblets form one, or rarely two, strap-shaped leaves, they go dormant. Place the containers or flats in a cool environment (root cellar, refrigerator, a non-freezing, approximately 40°F garage). Keep the flats moist, but avoid over watering to prevent fungal growth. They need about two months of cold temperatures to break dormancy.

Depending on the time of year, the bulblets can be returned to the warm room or greenhouse in late spring to encourage new growth. The tiny bulblets can also be planted directly outdoors in a warm, sunny location. Some cultivars may bloom during the second summer, but the flower display is best beginning in the third summer.