The green rose is an unusual and intriguing botanical phenomenon. While most rose bushes produce flowers in shades of red, pink, yellow, orange or white, some varieties of roses can appear in green. But are green roses real? Or are they somehow artificially colored or genetically modified? In this article, we’ll examine the facts around green roses and whether they occur naturally.
What causes green roses?
Most rose bushes have genes that code for pink, red, or yellow pigmentation. The pigments come from compounds called anthocyanins. However, some roses have a genetic mutation that blocks or reduces anthocyanin production. This results in white or paler colored roses due to lack of pigments.
Green roses arise when these pale roses also have a second genetic mutation that results in high levels of chlorophyll production in the petals. Chlorophyll is the green pigment used by plants for photosynthesis. With high chlorophyll and low anthocyanins, the rose petals take on a green color.
This double mutation – blocking anthocyanins and boosting chlorophyll – occurs rarely. That’s why green roses are unusual. Only a handful of rose varieties have displayed natural green coloring.
Examples of naturally green rose varieties
Here are some of the rose varieties where green flowers have been documented:
- Rosa chinensis viridiflora – Also called the “green rose of China,” this was the first documented green rose bred in the 1840s. It has light green single petals and yellow stamens.
- Rosa ‘Chartreuse de Parme’ – Discovered in the 1840s, this rose has double blooms that emerge light green and mature to darker green with hints of purple on the outer petals.
- Rosa ‘Green Ice’ – Bred in 1999, this modern repeat-blooming hybrid tea rose has creamy double blossoms that change from yellow-green to lime green.
- Rosa ‘Gruss an Aachen’ – An older floribunda rose bred in 1909. It can occasionally produce green-tinted blooms.
| Rose Variety | Color | Type | First Discovered |
|---|---|---|---|
| Rosa chinensis viridiflora | Light green single petals | China rose | 1840s |
| Rosa ‘Chartreuse de Parme’ | Double light to dark green blooms | Old garden rose hybrid | 1840s |
| Rosa ‘Green Ice’ | Creamy yellow-green to lime green doubles | Modern hybrid tea | 1999 |
| Rosa ‘Gruss an Aachen’ | Occasional green-tinted blooms | Floribunda | 1909 |
As the table shows, documented green rose varieties have existed for over 100 years. The older China rose and European varieties likely occurred by random genetic chance. The modern green roses were intentionally bred by rose hybridizers exploring the rose color spectrum.
Are artificially colored roses “real”?
In addition to naturally occurring green roses, some florists and growers have produced apparently green roses through artificial coloring techniques. These involve either dyeing white rose blooms by submerging their stems in colored water or ink, or spraying the blooms with green paint or lacquer.
While this can produce green-looking roses, most observers would not consider these artificially colored blooms to be “real” green roses. The color is not organic to the living plant. It won’t be passed on through propagation. And the blooms may lose their vivid color quickly as the artificial dyes and coatings fade.
Genetically modified green roses
Recent biotechnology research has succeeded in genetically modifying roses to alter their flower colors. In 2019, Japanese scientists announced they had used RNA interference technology to turn a deep red rose light green. By suppressing a gene responsible for anthocyanin production, they reduced the red pigments to create a greenish hue.
However, these genetically engineered green roses are controversial. Critics argue that genetically modifying the roses is an extreme intervention that violates the natural genetics of the plants for novelty value. They are concerned about potential risks if genetically modified roses escaped into the wild and spread.
Supporters counter that genetic modification is simply a high-tech way to achieve desired traits more quickly than traditional breeding. They believe scientifically designed roses are as valid as those created through cross-breeding – and could even allow the creation of unique new rose colors.
Does sunlight exposure affect rose color?
Some rose hobbyists have observed that their roses can take on different hues based on sunlight exposure. A red rose grown in full sun may appear vivid scarlet. The same variety grown in partial shade may have a more purple or magenta cast.
There are a few factors potentially at play:
- Sunlight encourages the production of anthocyanins. Lower light can reduce concentrations of these red pigments.
- Chlorophyll concentrations may increase with less sun. Higher chlorophyll could shift red toward green.
- Our visual perception of color is influenced by surrounding light. A rose may appear more vividly red in bright sunlight versus shade.
So while sun exposure doesn’t fundamentally change the genetics behind a rose’s color, it can impact the visible color by altering pigment concentrations and our visual color perception.
Can soil chemistry impact rose color?
There is limited evidence that certain minerals and compounds in soil could marginally impact rose flower coloration. However, soil chemistry has nowhere near the influence that genetics does in determining bloom colors.
Some examples:
- Acidic soils may promote anthocyanin production, creating deeper reds.
- Alkaline soils may reduce available iron, creating paler yellows or whites.
- High phosphate fertilizers could result in darker foliage and richer reds.
However, these potential effects would be quite minor compared to the underlying genetics of the rose plant. While soil factors may finesse the final color, they won’t override the basic color spectrum encoded in the plant’s DNA.
Could radiation create green roses?
Radiation has been shown to cause genetic mutations that can alter flower colors. Exposing a normally red rose bush to radiation theoretically might damage the genes controlling anthocyanin production. If this was coupled with higher chlorophyll levels, it’s conceivable that radiation could generate a random green rose.
However, radiation mutagenesis of plants is considered controversial and potentially hazardous. Researchers must take great care to avoid environmental contamination with uncontrollable mutated organisms. The consensus is that radiation-induced mutations are an unwise way to manipulate plant genetics compared to modern biotech methods or traditional breeding.
There are isolated stories of hobbyists reporting spontaneous off-color buds after storing dormant rose canes in an x-ray machine. But radiation is not considered a legitimate way to intentionally generate new rose colors.
Can roses change color as they age?
Rose blooms can change shades as they age, mostly due to pigment breakdown:
- Bright reds may fade to more of a crimson or pink tone
- Yellows may become paler and more whitish
- Darker purples may lighten toward lavender
However, roses won’t dramatically change hues, like a red rose becoming yellow. The underlying genetics control the boundaries. For example, red roses with low anthocyanins may lighten to pink, but won’t shift all the way to green or blue undertones without genetic mutations.
Conclusion
In summary, green roses do exist in nature, albeit rarely. A genetic fluke that suppresses anthocyanin while allowing chlorophyll can result in true green blooms. However, artificially dyed or painted roses are not considered genuinely green by most observers.
Modern biotechnology may allow intentionally engineering roses with new colors. But classical breeding focused on isolating natural genetic mutations has also produced green rose varieties over the past two centuries, albeit sporadically.
While factors like sunlight, soils and age can slightly alter the nuances of rose coloration, the core genetics fundamentally determine whether a green rose can be naturally expressed. The legendary green rose remains an elusive and magical botanical phenomenon.
