Bulbs such as onions and daffodils store food underground so the plant can regrow each spring.

The longer version

A bulb is a short underground stem wrapped in thick, fleshy leaves that hold starch. Those layers are the plant's reserve, built up during the growing season and kept safe below ground through cold or dry months.

When conditions improve, the stored food fuels rapid growth before the leaves above can photosynthesise properly. Because the shoot is already formed inside, the plant can flower early and finish its cycle quickly. Offsets develop beside the original bulb, so a single one gradually becomes a cluster. Because the reserve sits below the surface, a bulb survives frost that would kill leaves exposed to the air.

Where this entry sits

Plants and Trees gathers ordinary and surprising details about how green things live, from the tallest forest giants down to the moss on a garden wall. Expect notes on flowers, seeds, roots, leaves, fungi, and the quiet tricks plants use to spread and survive. The full list sits on the Plants and Trees page, where every entry is listed in order.