What’s inside a bulb
The anatomy of the underground storage system
Most true bulbs, such as onions and daffodils (see left) comprise a basal plate at the base where the roots grow from. Then there are layers of scales, which are the leaves in their embryonic state and both store energy and protect the inner workings of the bulb, namely the stem and flower. There is a thin outer skin, called a tunic, which helps stop bulbs drying out, and the shoot, comprising the developing flower and leaf buds. When planting bulbs, it is important to get the base plate pointing downwards, so the roots can grow down and the shoot can grow upwards towards the light. Lily bulbs don’t have a tunic, so the scales are exposed. These scales can be snapped off, put in a bag with damp, gritty compost, somewhere warm, and new bulblets will develop. A tuber just has a storage root and a plant bud. Dahlias are an example. Dahlia tubers can be divided in spring after they’ve sprouted – ensure each section has both shoot and storage root. A corm is a swollen stem that has been modified into a storage organ. It has a basal plate, tunic and growing point. Clumps of crocosmia corms like these can be dug up in spring and the individual corms replanted to develop into new plants.