Hydrangea (Hydrangea) is a perennial decorative flowering bush, often grown in gardens. Florists and florists love it for plentiful and long flowering, for large, spherical inflorescences, which can be pink, red, blue, violet or white. But sometimes garden hydrangea changes its usual shades. From the article you will learn what the color of the petals depends on, why the color of hydrangea changes and what affects such metamorphoses. And also - how to return the desired color back.
Reasons for color change
Color changes in plants and flowers can occur for several reasons. In some species, the color changes as the flower ages or ripens, in others, depending on the illumination of the growing place. And only one plant - large-leaved hydrangea (Hydrangea macrophylla) can be manipulated to change color from pink to blue (and in all intermediate shades) during growth, using additives to change soil characteristics.
Large-leaved hydrangeas are distinguished by their ability to change color in response to soil conditions, namely the acid-base reaction, and the mineral composition of the soil. The natural factor that causes petals to stain is the presence of anthocyanins, water-soluble pigments found in plant cells.
In soil with a higher pH, aluminum absorption is blocked, and a lack of mineral always leads to pink flowers. Thanks to genetic modification, specialists can change the pH in plant cells to create flowers in new shades. Plant genes determine the color of a flower in the same way that human genes control eye color. By making plant cells more acidic or more alkaline, pigments can also be changed: red colors from flavonoids, yellow and orange from carotenoids, and green from chlorophyll. Changing the levels of these pigments in various combinations creates new colors in the same way that mixing paints produces different shades. Scientists even use the genes of one plant to create color changes in a plant of another species.
The colorfulness of the color depends on the complex processes of pigmentation and reflection of light and serves to attract pollinating insects. But sometimes the colors fade and the flower looks wilted. Such changes can be affected by heat and too bright sun. Some inflorescences lose their color after pollination. Transplanting to a new place can also cause a change in the brightness of the petals, so you need to give the plant time to adapt and get used to another site. But the most important factor, on which the color change of hydrangea inflorescences largely depends, is the acid-base balance of the soil.
Soil acidity
The soil acidity level is indicated by the Latin letters pH and is measured in numerical values, where neutral soils correspond to indicators of 6.5-7.0. At lower values, the soil has an acid reaction; at higher values, it has an alkaline reaction. Thus, the pH level must be changed to transform the color.
The color shades of hydrangea inflorescences depend on these acid-base indicators, and the color is determined by the pH level of the soil in which the bush is planted:
- in acidic soil with a pH below 5.5, these plants produce blue flowers;
- in the earth with a neutral or alkaline pH value (6.5 and above) the inflorescences leave pink;
- soil acid levels between these numbers can cause hydrangea to produce lavender and purple hues of the petals, or even blue and pink on the same plant.
But not all hydrangeas can change color depending on soil characteristics. This possibility applies only to varieties with pink and red inflorescences (shades of pink, blue, red, red-violet).
Important! Before making any adjustments to the ground, whether it is a change in the color of hydrangea or an increase in the content of nutrients and elements, always test the soil in the area. And then re-check to make sure the pH is in the right range.
White hydrangeas always remain white, regardless of soil acidity. They do not undergo blooming, because they do not have anthocyanins responsible for the color of the petals, and the flowering of some varieties of hydrangeas, such as Pia, Masya, Alpenglyuchen, will remain red-pink, regardless of how acid the soil becomes.
The presence of phosphorus
To make the flowers pink or red and keep them in this form, phosphorus top dressing should be used.When fertilizing plants for large inflorescences and their rapid formation, preference should be given to nitrogen-phosphorus compounds with a low potassium content (approximate composition NPK 10:30:10), monoammonium phosphate can be used.
Phosphorus, reacting with aluminum in the soil, creates compounds from which the plant will not be able to assimilate metal. Fertilizers should be applied sparingly - in the spring, when leaves appear, and again in the middle and at the end of summer.
Aluminum
The color mechanism of hydrangea is not directly dependent on the pH of the soil. But acidity affects the ability of a plant to absorb the chemical components of the soil, and in the case of hydrangea blooms, aluminum is a critical element.
An acid reaction releases aluminum from its compounds and makes it available to the plant. When hydrangea absorbs this metal, its flowers turn blue. As the soil becomes less acidic with this consumption, the amount of available aluminum decreases and the flowers turn pink again.
Did you know? Each color of hydrangea has its own meaning: pink represents love and sincerity, blue - forgiveness, white - boasting and vanity, purple - abundance and understanding.
Gardeners sometimes dig aluminum foil at the base of the bushes to paint the petals blue and provide a sufficient amount of available metal in the soil. But it is poorly soluble in the earth and its absorption by plants is hindered by surface oxide films, which cover all aluminum compounds.
Since too much aluminum can be toxic to plants, the initial choice of pink flowers is healthier and more environmentally friendly. Procedures for changing the shades of a flower are effective only when they begin long before flowering.
Why did pink hydrangea turn white and vice versa
The reason for the fading of bright pink petals to white is most likely due to sunlight.Hydrangeas bloom best when planted in a place that receives the morning sun and some shading at noon. Too much shade reduces bloom, while the abundance and brightness of sunlight whitens or partially discolours inflorescences, and can lead to wilting of plants.
At the same time, certain varieties of panicle hydrangea with lush cream-white inflorescences gradually turn pink during the summer months and acquire such a shade with age (Phantom, White Diamond, Bobo, Silver Dollar). During the flowering period, they can acquire a pink color along the edge of the petals, and some at the end of it become a light dusty pink hue. There are varieties that reach even deeper pink-bronze or terracotta tones in the fall.
How to water hydrangea so that it turns pink
Gardeners can control the color of hydrangeas by adjusting the acidity of the soil. If the soil in the garden has an alkaline reaction, pink hydrangea flowers appear on their own. When choosing a place for planting, you should pay attention to herbs that prefer alkaline soil - this is chamomile, nettle, white clover, quinoa. So you can determine the high pH level without chemical analysis.
Important! Try not to go to extremes. Excessively high soil pH binds essential trace elements, along with aluminum, which are essential hydrangeas to maintain health.
An approximate assessment of the soil can be done in a simple way by moistening a handful of soil with table vinegar - alkaline earth will hiss and foam will appear.For other indicators, in order to make hydrangea bloom in pink flowers, it is necessary to suppress the ability of the plant to absorb aluminum from the soil.
A slight increase in pH by adding lime, chalk, dolomite flour can increase the saturation of pink shades of inflorescences. For a long-term result, apply 200 g of granulated dolomite lime for every 1 m² of plantings once a year. In order to achieve faster changes, water the bushes with a solution of 1 tbsp. l slaked lime per 4 liters of water once a month for three months of spring (in March, April and May). Adjust your watering schedule about a month earlier if flower buds form faster this season. Choose any of these methods to obtain pink inflorescences.
Wood ash will also increase the pH of the soil. It works faster than limestone and adds potassium and trace elements to the soil. But you should be careful when making wood ash - this is a very concentrated composition, so too much of it can dramatically change the pH and cause an imbalance of nutrients. Wood ash can also burn foliage, so for best results, apply it directly to the soil in winter. Use no more than 1 kg per 10 m² every 2-3 years, and check the soil every year to monitor the effect.
During the growing season, hydrangeas can be watered with an ash solution (100 g of wood ash per 10 l of water), which also helps to reduce the acidity of the soil.Hard water with a high content of calcium, which binds aluminum, contributes to the deoxidation of the soil, therefore, in order to maintain the pink color of the petals, it is not necessary to water the plants with rain soft water.
Changing the pH of the soil may take some time, so immediate results should not be expected. Well, watering with watercolors or gouache, potassium permanganate or ink will not change the color of hydrangea at all, but can only harm the plant.
Did you know? There is Hydrangea Day - January 5th, which is celebrated by all lovers of this plant. Winter is not the season for flowers, but you can enjoy them at any time of the year if you dry them.
Hydrangeas are rightfully considered the symbol and glory of summer. These flowering beauties, full of vitality, are deservedly popular and can decorate any corner of the garden. A curious gardener may try to change the color of their luxurious flowers with simple methods.
