Inside a true bulb is a central shoot that contains layers of leaves and immature flowers. With bulbs planted in your garden, this central shoot forms after flowers fade. This is why it’s important to let leaves of bulbs like tulips and daffodils remain and stay green until they naturally die back. As long as leaves are green, they’re helping to store food that helps form the shoot for next year’s show. Most true bulbs have a protective papery skin (think onion, daffodil, tulip). An exception to this rule are the lilies, including Asiatic and Oriental types.