True lilies: It’s all in their bulbs



True lilies are distinct plants with characteristics demonstrably different from other flowers grown from bulbs, such as tulips, narcissus (daffodils and jonquils), and the ornamental onions (Allium). Lilies do not have a protective papery sheath holding and protecting the interior layers (in tulips this is called the tunic). Lily bulbs have overlapping scales exposed to invasion by fine clay particles in unamended soil, particles that can hold water, rotting the bulb. This explains why true lilies love quickdraining sandy loam. They should be planted in beds where gardeners will not tread over them while they are dormant, which would work heavy clay down into the deep soil layer where the bulbs are. True lilies form roots along the buried section of stem that emerges from the bulb and grows up through the soil with the flower buds atop—known as stem roots. There are also roots at the base of the bulb, gleaning water from the earth, and these
lowest roots also adjust the depth of the bulb by contracting to pull the bulb lower if the clumsy gardener has not placed the bulb to its liking. (Don’t you wish all plants were self-correcting?) The stem roots, growing between the bulb and the soil surface, absorb nutrients and brace the heavy flower stem. Thus most lilies have two sets of roots that perform separate functions, with the deepest roots providing water from down where moisture levels are relatively consistent, and the upper stem roots spreading laterally to provide stability. Pretty smart. But the real brains of the operation is the bulb’s basal plate. This is the woody disk at the base of a dormant bulb that generates the contractile roots and holds all of the scales in their upright, overlapping configuration, like an artichoke’s leaves. The flower stem pushes its way up through the scales directly from the basal plate. Also, the basal plate houses the plant’s unique DNA. Whether the lily you grow is a species or a hybrid, the basal plate contains the bulb’s identity, passing it along to the scales, to the baby bulbs (bulblets) that form from the plate, to bulblets that form at the junction of the stem roots and the flower stem, and to the tiny bulbs (called bulbils) that
form above ground at the leaf axils in some species. The basal plate also provides the genetic information in the pollen on the anthers and the eggs (ovules) in the ovary. In short, the basal plate tells every part of the lily how to look and what to do. Thus, when buying lilies, you should know that getting big bulbs is only part of the successful equation. Always examine the basal plate of the bulb you are selecting. In dormant bulbs it should be dry and woody. If it is spongy or has brown pithy areas, it is afflicted by basal rot (usually a botrytis fungus), and the whole bulb should be discarded. The contractile roots that may have been left on the bulb should also be firm and dry. Darkened wet roots on newly purchased bulbs should be pulled off; they are starting to decay and that decay can spread.

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