Are all rose colors natural?
Roses come in a variety of beautiful colors, from classic red to vibrant pink, sunny yellow, and even deep purple. While red roses are the most iconic, rose breeders have worked for centuries to develop different rose colors and hues. This has left many gardeners wondering – are all rose colors natural, or are some the result of human intervention?
The genetics behind rose color
The color of a rose is determined by pigments in the petals. The main pigments that influence rose color are:
– Anthocyanins: These water-soluble pigments produce red, purple, and blue hues. The most common anthocyanin in roses is cyanidin. Higher concentrations result in deeper red hues.
– Carotenoids: These fat-soluble pigments produce yellow, orange, and pink shades. The most prevalent carotenoids found in roses are lutein, zeaxanthin, and beta-carotene. More carotenoids lead to more vibrant yellows.
– Flavonoids: These supplementary pigments modify the color produced by anthocyanins and carotenoids. They can mute reds towards pink or purple and temper bright yellows.
The genetics of the rose variety determines how much of these pigments are present in the petals. Roses inherit their pigment levels and profiles through crossbreeding. Breeders select parents with desired colors to produce new rose shades in offspring.
Natural rose colors
Most rose colors arise naturally from the pigments discussed above. These include:
Reds – From light pink to burgundy, red roses get their hue from high anthocyanin content. Traditional red roses are the result of breeding selections, not genetic modifications.
Pinks – Pink roses contain moderate levels of anthocyanins complemented by yellow and orange carotenoids. Breeding achieves delicate pinks.
Whites – White roses lack virtually all pigments. They are not albino plants, but rather selections that do not produce anthocyanins or carotenoids.
Yellows – Yellow and yellow-orange roses get their bright colors from abundant carotenoids in their petals.
Purples – Purple roses combine high anthocyanin levels with specific flavonoids to achieve their unique hue.
Oranges – Breeding has produced orange roses with enhanced carotenoid content compared to yellow varieties.
Blues – True blue roses do not exist naturally. However, breeders have used genetic modification to create blue-hued roses by inserting a blue pigment gene from pansies.
Achieving new colors through breeding
While the earliest cultivated roses were white, pink, and red, breeders have introduced a much wider spectrum of colors over centuries of selective crossbreeding. Some noteworthy examples include:
Yellow roses – Yellow and yellow-blend roses did not exist until the late 18th century. In 1799, the first yellow rose arose from a cross between the Rosa foetida persiana and old European roses.
Orange roses – Orange roses were bred in the 20th century by crossbreeding yellow varieties with red roses. This boosted carotenoid levels to create vivid orange hues.
Black roses – Truly black roses do not exist naturally. However, very dark red and purple roses are marketed as “black” roses. Their dark hue comes from specialized breeding with purple-leaved Rosa chinensis.
Green roses – Breeders can cross white roses lacking pigment with faintly green-tinted Rosa chinensis to achieve greenish petals. However, the color is often subtle.
Through similar dedicated breeding over decades and centuries, rose growers have developed diverse rose shades spanning the entire color wheel. With patience and diligence, breeders continue to create new rose colors today.
Genetic engineering for true blue roses
While traditional breeding has yielded many new rose colors, it has not been able to produce truly blue roses. Blue pigments require complex biochemistry that roses do not naturally possess. To achieve blue roses, scientists turned to genetic engineering to insert genes from other blue-pigmented plants:
– In 2004, researchers in Japan used engineered roses with two blue pigment genes from pansies. This created the world’s first engineered blue roses.
– In 2009, an Australian company developed more vibrant blue roses using delphinidin from blue irises.
– The latest blue rose debuted in 2018 from an American company. It contains a gene from blue Virginia mallows.
Importantly, genetic engineering allows the exact genes for blue pigment production to be inserted into roses. Conventional breeding could not transfer the more complex traits needed for true blue color.
Today, beautiful blue rose varieties are available thanks to genetic engineering. However, many consumers prefer naturally bred roses over genetically modified options. Blue roses represent an exception where engineering was required to achieve an elusive color.
Creating multicolor roses
Using tissue culture cloning, rose breeders can even produce individual roses that display more than one color on the same bloom or plant:
Bi-color roses – These have petals of one color which transition into another hue towards the base of the flower. Common color combinations include red-white and yellow-pink.
Ombré or splash roses – Ombré roses gradually blend between two colors. Splash roses have splotches of a secondary color painted onto a main background color.
Striped roses – Stripes of contrasting pigments run through the petals. Breeding allows great diversity in stripe color and pattern.
Edge roses – Only the outer perimeter of the petals displays a different color than the main rose hue.
Picotee roses – A thin ring of contrasting color decorates the petal edges.
Flecked roses – Tiny flecks of a secondary pigment are sprinkled across the bulk rose color.
These mosaic roses provide unique, eye-catching options for gardens, floral arrangements, and gifts. The multiple colors are achieved by selectively propagating color bud mutations.
Are dyed roses natural?
In addition to breeding and bioengineering, some rose colors are attained through artificial dyeing:
Dyed blue roses – Since true blue roses are still somewhat rare, florists will dye white roses to appear blue using dye injected into the stems. However, the color is temporary.
Dyed black roses – Black dye gives roses a gothic effect. But like dyed blue roses, the color is only superficial. Once the dyed water is gone, the roses turn back to red or other natural shades.
Artificially dyed roses enable florists to offer trendy hues at low cost. However, they lack the permanence and vibrancy of naturally bred or genetically engineered rose colors. The dye can also leach out over time.
Conclusion
While new technologies like genetic modification have created novel rose colors, the vast majority of rose shades arose completely naturally through deliberate breeding selections. Crossbreeding heirloom rose varieties with desired pigments has yielded an expansive palette over centuries. Today, classic favorites like red, pink, white, and yellow coexist with modern hybrids in sunset orange, lavender purple, and ombré two-tones. For roses, naturalness remains closely tied to their enduring romance and beauty. With patience and creativity, rose breeders can continue developing new dazzling hues.
| Rose Color | Pigments Involved | Genetic Origin |
|---|---|---|
| Red | High anthocyanin content | Natural breeding selections |
| Pink | Moderate anthocyanins with carotenoids | Natural breeding selections |
| White | Lack of pigments | Natural breeding selections |
| Yellow | High carotenoid content | Natural breeding selections |
| Orange | Enhanced carotenoids | Natural breeding selections |
| Purple | Anthocyanins with specific flavonoids | Natural breeding selections |
| Blue | Engineered pigments from other plants | Genetic engineering |
