Hydrangea plants come in a lot of pretty colors like blue, pink, lavender, and cream. So, it can be a bit off-putting to see your hydrangea with green flowers.
Here are a few reasons why your colorful hydrangea flowers might start turning green.
#1. The life cycle of hydrangeas
One of the most common reasons why hydrangea flowers turn green is because of the life cycle of hydrangeas. Hydrangea flowers turn green as they age.
The flowers react to the changing seasons and as they age, begin to change colors. They start with their original color, then soon turn green and eventually brown by the end of the season.
The colors of hydrangea are constantly changing. Usually, the young flowers are much brighter and richer in color. As they age, they lose color.
Many white hydrangeas turn green as they age. This is because the white petals of the flowers are actually sepals, which are the green leafy parts behind the flower.
Sepals are naturally green in color, however, in hydrangeas, they come in different colors. So, after a few weeks of blooming, the flowers start turning green.
This happens in all hydrangeas, but it is very noticeable in the white ones. Some turn green even when their original color is white. This can be seen in Incrediball and Annabelle’s hydrangeas.
Some varieties turn pale pink as they age. But no matter what, in the end, all the flowers turn brown and eventually die out.
Hydrangea flowers changing colors due to aging does not cause any problem to the plant. It is not an indicator of environmental stress.
This happens because the concentration of the color pigments in the flowers changes through the seasons and the flowers turn green by the end of summer. At the peak of summer, some flowers can even get burnt due to the heat.
In this regard, hydrangeas are not like other flowering plants. The color of the flowers does not remain constant until it ages. As the season’s change, so does the color of hydrangea flowers.
The rate at which hydrangea flowers change colors and turn green depends on the variety of the flowers. Some species of hydrangea turn green a lot quicker than some other varieties.
Sometimes, a change in the acidity of the soil can also cause some varieties of hydrangea to change the color of their flowers, sometimes from blue to pink.
#2. Daylight hours
The length of daytime during the day also plays a role in the hydrangea flowers changing to green. Hydrangeas need up to 6 hours of sunlight during the day on average.
When the hours of daylight in a day are less, especially in winters, hydrangea flowers can turn green. The flowerheads need energy from the sun to produce the color pigment that gives the colors blue, pink, and white to the blossoms.
With fewer sunlight hours, the flowers get less energy. Thus, they are not able to produce enough pigmentation, leading to the flowers fading from their original color to green during late summers.
Hydrangeas usually start turning green by the second half of the summer. This is the time when daylight hours start decreasing. This is also the time for seed formation.
The plant needs energy for seed formation, but it does not have enough, so the petals also take part in the process of photosynthesis.
That is why, hydrangea flowers mostly turn green towards the end of summer, while during spring, they are colorful.
However, this does not mean that you need to place your plant in full sunlight so that the plant will have colorful blooms.
Hydrangeas are woodland plants and they cannot grow well in direct sunlight. It can cause leaf scorch and turn the flowers brown.
Always plant your hydrangeas under a canopy, or where it will get morning sunlight and afternoon shade.
#3. Heat and humidity
Heat and humidity are some of the apparent reasons why hydrangeas turn green. These causes of hydrangea flowers turning green have been found more prevalent in climates that are hot and humid.
While the exact reasons for this are not known, hydrangeas are plants that require the soil to be consistently moist so that the flowers and leaves don’t start wilting.
Hydrangeas like water. If they do not get enough water, they can turn green and then eventually brown.
If the temperature in a region is high, the moisture evaporates faster and the roots cannot absorb moisture from the soil at a matching pace. This is the reason why the plant gets stressed.
This stress, along with the humidity in the region, can speed up the process of the hydrangea flowers changing from their original color to green or even brown.
Hydrangeas can live in areas with some amount of heat and humidity. However, in nature, hydrangeas grow in woodlands, in the shade of large trees.
They constantly receive diffused light and are not at risk of overheating or sunburns. So, this could be a reaction to a different environment.
#4. Color changes in hydrangeas
Hydrangea has the ability to change the color of its flowers. The color of the flowers depends on the pH of the soil in which it is planted.
A high pH means that the soil is more alkaline, which makes the color of the hydrangeas pink. Soil with a low pH means that it is acidic, making the hydrangea blooms blue in color.
You can change the color of some varieties of hydrangea. If you want the flowers to be bluer, you can add aluminum sulfate to the soil. Adding dolomite makes the hydrangea blooms pink.
White hydrangeas don’t usually have the ability to change colors, but a few varieties of white or cream hydrangeas can turn pink.
It is believed that when the aluminum in the soil is depleted, the color of the hydrangea can fade to green. Check the pH of the soil. To control the color of the blooms, you can add aluminum sulfate to the soil.
Your soil needs to be sufficiently acidic. If it is more alkaline, it will inhibit the absorption of any aluminum sulfate that you add to the soil.
#5. Naturally green
There are a few varieties of hydrangea that have naturally green flowers.
One of the varieties of hydrangea is Limelight hydrangea. This hydrangea can grow in full sunlight as well as in partial shade.
Limelight hydrangea grows up to 3 feet tall and 2.5 feet wide at the peak of its maturity. Most of the time, the flowers of Limelight hydrangea are lime green in color.
Another variety is the Little Lime. Little Lime is a dwarf version of the Limelight hydrangea. This plant rarely exceeds 2 feet in height or width.
The petals are more greenish than the Limelight variety as this plant grows at a slower rate. Little Lime is a better plant for you if you have a small garden.
There are also some varieties of Hydrangea Macrophylla with pure green flowers. The color of the flowers of these plants is very bright green, and they look very unique.
Should you deadhead green hydrangeas?
Deadheading, or the process of removing the faded flowers from a plant, will promote the growth of new blooms that will be bigger and more vibrant. If your green hydrangea blooms have wilted, you can remove them.
Hydrangea blooms turn green as the seasons change. So, if you are thinking of deadheading your green hydrangeas in the hope that your blooms will return in their original blue, pink, or lavender colors, you might not get the results that you want.
However, it is not an issue for your plant if it turns green, and green flowers also look good. So, try to deadhead your green blooms only after they start wilting.
All you can do to minimize the risk of your blooms turning green is to look after the needs of your plant such as the proper soil, nutrition, water, and sunlight.
However, your hydrangea can still turn green no matter what you do for it.
How to stop hydrangeas from turning green?
If your hydrangea flowers turn green in color, there is not much you can do to get them back to their original color immediately. But you can take some measures to prevent any color changes in the future.
You need to provide your hydrangea with dappled sunlight. Your plant should get plenty of sunlight but in a diffused form. Direct or harsh sunlight on the hydrangea can scorch the plant.
This is very important especially for plants like bigleaf hydrangea and hydrangea paniculate.
The watering method plays an important role in the color changes in your plant. Hydrangeas require plenty of water. You should water the plant sufficiently so that the entire root system can get enough water.
Before you water the plant, you need to check the soil to see if it is dry or moist. The soil should be dry 1 to 2 inches but not more than that. Avoid watering the plant frequently, as it can lead to root rot and yellow leaves.
Before you plant your hydrangea, add 2 to 3 buckets of compost or peat in the planting hole so that the soil becomes looser. It will also make the substrate drained.
You can try to take measures to help prevent your hydrangeas from turning green, but there is no guarantee that they will not turn green. So do not get discouraged if that happens. Your plant will get colorful blooms again in one or two seasons.