Some orchid flowers do change color. This is related to the age of the flower, and in many cases orchid blossoms will darken in color just before dropping from the stem.
About Orchid Blooms
Most orchids will bloom once a year, sending up one or more flower stalks from which multiple flowers spring. With the proper growing conditions, orchid flowers can persist for weeks and sometimes months.
Orchid Color by Variety
Orchid flowers appear in every color of the spectrum, in nearly every climate in the world. Flowers range from creamy white to deep magenta, and some of the showiest species have color variations on each bloom.
Orchid Growing Conditions
Indoor growing conditions must be just right for orchids to flower. Most orchids prefer bright, indirect light, nighttime temperatures between 55 to 60 degrees and high relative humidity.
How Color Change Occurs
Most orchid flowers will retain the same color throughout the blooming cycle. But just before the flowers wither and fall, some flowers will deepen in color, turning from white to pink, or from pink to a darker shade. Veins are often more prominent during this color change.
Breeding Effects on Flowers
Orchid breeders attempting to achieve permanent bloom color in individual plants may cross one plant with another in which the plants have been selected for color features. This may result in offspring with flowers of a different color than the parents.