Can Hibiscus Be a Light Golden Color
The Mystery of Hibiscus Colors
Why do hibiscus flowers change color?
'Heavy Metal' in Heat
Anthocyanins Burn off, leaving White Spots under Red.
Carotenoids Increase, turning Edges Bright Yellow.
One of the most fascinating, albeit frustrating, characteristics of hibiscus is the way the flower colors change. A few hibiscus produce the same colors at all times of year in every kind of weather. But the vast majority of hibiscus change their colors with changes in temperature, hours of daylight, and who-knows-how-many other variables! In this article we will explain at least some of the color changes that hibiscus go through.
'Heavy Metal' in Winter
Anthocyanins Increase, Turning Flower Solid Red.
Carotenoids Decrease, Softening Edges to Orange.
Carotenoids ~ The Yellow, Orange, Red Spectrum
'Gold Mine' in Winter
Cold Weather Decreases Carotenoids.
Flower Opens and Stays a Soft Orange
Carotenoids Hold their Color
'Gold Mine' in High Heat
Carotenoids Increase
Making Vivid Red & Yellow
Hot Weather Increases Carotenoids
'Saffron' an Example of a Bloom
With High Levels of Carotenoids
Making our Most Vivid Orange
It works the same with hibiscus. The hotter it gets, the brighter the orange and yellow flowers get. 'Gold Mine' and 'Saffron' are good examples. In hot, sunny, summertime heat, 'Saffron' blooms with vivid orange flowers, and 'Gold Mine' is bright red with vivid yellow markings. In cool cloudy weather, both these hibiscus bloom with paler orange or even golden-colored flowers, and 'Gold Mine' loses its yellow markings completely.
'Sleeping Beauty' in Cool Weather
Anthocyanins & Flavanols Increase
Making an Array of Beautiful Colors
The Blue, Purple, Pink, Red, Black Spectrum
Anthocyanins are best known as the red pigment in fall leaves. We all know that fall leaves change color in response to weather conditions, and this is the hallmark of anthocyanin pigments. Anthocyanins are plentiful in hibiscus, giving the flowers their many showy bands of color, as well as their tendency to bloom with different colors depending on many different variables.
'Sleeping Beauty' in Warm Weather
Anthocyanins & Flavanols Decrease
Decreasing Color Bands
Anthocyanins are a much different kind of pigment. They are much less stable than carotenoids. Anthocyanins aren't safely enclosed in plant cells. They are created in the roots, dissolved in the water that makes up plant sap, and move all the way up the plant to where the flowers develop. The least little change in the environment or health of the plant affects the sap, which means it also affects the anthocyanins. This is why blues and purples tend to be so changeable in hibiscus flowers - they are produced by the notoriously unstable anthocyanin pigments.
'Sleeping Beauty' in 2nd Day of Heat
Anthocyanins & Flavanols Burn Away
Colors Fade Almost Completely
Anthocyanins Increase and Turn Red in Response to Cold
'High Voltage' in High Heat is White
Red Anthocyanins Burn Away in Heat
'High Voltage' is Pink in Winter
Red Anthocyanins Increase in Cold
Anthocyanins Degrade and Disappear with Heat
Some anthocyanins are very sensitive to heat. Enzymes in plant sap completely destroy several of the anthocyanins in hot weather and bright sunlight, and this creates the fading effect we see in so many hibiscus flowers in summer heat. These are the hibiscus that we recommend keeping in partial shade during the heat of the summer, like 'Sleeping Beauty.' Its anthocyanin pigments are beautiful in the cooler, cloudier times of year, showing a rainbow array of 5 different bands of color, and holding the color well. In summer heat though, the flowers have only 2-3 colors, and in bright sunlight, these colors fade very quickly. But a 'Sleeping Beauty' growing inside a house in a window that gets an hour or two of sun every day will bloom with a full array of colors that will last for 2-3 days. Inside a house, or in partial shade, the anthocyanins are protected from too much heat and sunlight.
Anthocyanins Increase Production and Show a Wider Range of Colors with Maximum Nutrition
'Blue Ballerina' with Good Nutrition
Anthocyanin Pigments Develop Best with Optimum Nutrition
Some hibiscus are very, very sensitive to this nutritional effect, and will even stop producing flowers all together if the sugar and protein levels in the sap get too low. Others will produce flowers, but the colors will be pale, or some colors will be missing. The health of the plant really does matter when the colors depend on anthocyanin pigments!
Flavonols ~ Pale Yellow, White Spectrum
'Acadian Spring' Opens with Soft Yellow Edges
Produced by Flavonols
'Acadian Spring' is a good example of a hibiscus flower that uses flavanols exclusively. It opens with a soft yellow flower that fades in sunlight and heat to almost pure white. In cooler weather, 'Acadian Spring' flowers open almost completely yellow and they don't turn white during the day.
'Acadian Spring' in Afternoon Sun
Flavonols Degrade in Sun and Edges Fade
Can Hibiscus Be a Light Golden Color
Source: https://www.hiddenvalleyhibiscus.com/misc/colors.htm