Flowering bulbs provide a good context for learning about plant features such as leaves, buds, and flowers. Many plants from bulbs are large and easily observed. They grow quickly and can be measured easily. Different kinds of bulbs provide contrasts in types of leaves and flowers, and size of the plants that grow from the bulb.

Most children are not familiar with bulbs at the beginning of the unit, although a few have grown them at home. They have a range of ideas about what the bulb is and how it will change over time. Some think it will become a "flower" (plant), others think it will not change, "it's already an onion." Some children think that a small bulb becomes a big bulb. At the end of the unit, some children expressed surprise that the plants from large and small bulbs can be very close in final size.