Do Tulips Close at Night?

Bulbs

• Tulip blossoms appear in spring -- when bulbs are properly planted. Tulip bulbs are typically planted in the fall, usually in October, so that the flowers may grow and bloom in early to midspring. Tulips, daffodils and crocus are all spring bloomers grown from bulbs, and all exhibit some of the same characteristics.

Temperature Effects

• Some spring-blooming bulb flowers, like daffodils, stay open once they've fully bloomed, despite weather conditions. Crocus and tulips, however, close up tightly during the night when temperatures are chilly. Because tulips bloom in spring and nights may still be cold, it is common for tulips to close every night after opening wide during the day to soak up sunlight. If the flowers don't close at night, this is not a sign that there is a problem -- only that temperatures are warm enough for tulips to stay open.

Growth Habits

• Tulips respond not just to temperature effects but to light. The flowers grow toward light, and blossoms may tilt in the direction of the sun whether they're planted indoors or out. The petals of tulip spread wide to receive light, but in nighttime cold they draw in toward themselves to protect the tender inner portion of the flower blossom.

Cut Tulips

• Tulips do not have to be planted in soil to close during the night. Even after they have been cut and placed in a vase, tulips continue to grow. Tulips grow up to 1 inch taller even after cutting and may keep their habit of closing at night and opening during the daytime. The phenomenon may be forced if flowers are deprived of light and placed in a cold location after they have been cut.