Do Lilies multiply?
Lilies do multiply but after 2 or 3 years they will need lifting and splitting. Lift the bulbs out of the soil and carefully pull off any attached bulblets. Replant the original bulb and that will flower better the following year. Also plant the bulblets but bear in mind these will take a couple of years to become established. If lily bulbs are left un-split, they will eventually be unable to flower as the bulblets take all the nutrients from the original bulb.