I overwinter our geraniums in the garage and I’m curious how the blooms dry and remain red all winter but are dead on this living plant?
The Gardener’s Answer
Hello, Richard from Kentucky: To answer your question simply, some flowers lose their color as the bloom ages while others do not. This is why when people make dried arrangements with their cut flowers they are choosing specific ones based on how long the colors and the bloom itself will hold up. There are certain blooms that last longer than others. The topic of bloom color is actually more complicated than one might think. Not to get too technical but the color we see is really light reflected from different plant pigments. Anthocyanidins are the main group of compounds that make up these pigments. Our perception of these colors may differ depending on the time of day, light conditions, moisture/nutrition levels, as well as changes in temperature. The fact that your geraniums are moved to a cooler space out of the direct sun may have an effect on the color fading or lack thereof. The main reason for bloom color is to attract pollinating insects. Although as gardeners we might think the colors are specifically for our satisfaction, and in some cases the flower color has actually been manipulated by scientists for gardening purposes, but the real purpose is for fruit production. As colors fade it can be an indication to pollinating insects that their service is no longer needed.