Potted flowering plants are traditionally given at Easter. Here's how to enjoy them longer:
Remove the yellow anthers from the flowers if the grower hasn't already. This will make the flower last longer and keep the pollen from spilling onto the white petals. Place it in bright but indirect light, in a cool room, for the longest-lasting flowers. Remove flowers as they fade. Water when the top inch of soil feels dry. Do not overwater. After all danger of frost has passed, you can transplant the lily to a well-drained location that receives morning sun and afternoon shade. Plant the bulbs 3 inches below the surface and pile an additional 3 inches of soil on top. If you are planting more than one, space them at least 12 inches apart. As the plant begins to die back, cut the stems to ground level. Apply a slow-release fertilizer. The plant may rebloom in fall or bloom next spring; eventually it will begin to bloom at its normal time, midsummer. Easter lily is the species Lilium longiflorum, hardy in Zones 3 through 10.
Keep pots of blooming bulbs—tulips, crocus, hyacinth, daffodils—in a bright, cool room, but out of direct sunlight. Water when the soil feels dry, taking care not to overwater. Once the flowers have faded, remove them. Leave the foliage as is. Move the pot to a sunny spot outside once the temperature remains above freezing and keep it watered. After the leaves die back, you can plant the bulbs immediately or wait and plant them in the fall. (Related: Can I plant potted tulips in my garden?)
Hydrangeas grown for the potted-gift trade can be challenging to keep in the garden; they are perhaps best enjoyed as a one-time seasonal houseplant and then discarded. They have been fed to produce many blooms on a relatively small plant, at the expense of their future health. Hydrangeas don't do well as permanent houseplants because they can't receive the winter dormancy they require (triggered by temps around freezing) or sufficient light and water. To enjoy your potted hydrangea for as long as possible, keep it in a bright but cool location and water it frequently. It may need water twice a day. The flowers can be pretty as they fade. If you do want to try transplanting it to the garden, do so in early spring, preparing the planting hole with plenty of compost and watering the plant well until it is established. Choose a sunny location. Potted hydrangeas are the species Hydrangea macrophylla and are appropriate for Zones 6 through 9. (Related: When to prune hydrangeas.)
Get a bunch of great resources on growing houseplants and gardening in containers for a special low price in the Growing an Indoor Garden Value Pack.
Find ideas and advice on non-traditional houseplants, including bulbs, perennials and shrubs, in Tovah Martin's The Unexpected Houseplant.