Majestic hydrangeas have a unique ability. Pink varieties of farmer's hydrangeas and hydrangeas shine in rich blue as if by magic. This miracle is based less on magic than on a low pH value of 4 to 4.5. Furthermore, white hydrangeas completely lack this talent. Would you like to be one of the secret keepers among hobby gardeners? Then explore how to dye hydrangeas blue here. After reading these lines, you will be familiar with the best home remedies for coloring, as well as other tricks - without any gardening latin.
Soil conditions set the course
Within the large hydrangea family, there are the garden hydrangeas - also called farmer's hydrangeas - and the plate hydrangeas, whose petals contain a special dye that reacts to the pH value of the soil. If the value fluctuates between 4 and 4.5, the hydrangeas develop a purple hue, which tends to pink and reddish as the values increase. To color hydrangeas blue, another component required is aluminum, which must be available in the soil for the shrubs. In alkaline soil with a pH value greater than 5, the lime binds the aluminum so that a hydrangea cannot absorb it through its roots. As an interim conclusion, it should be noted that the following two premises are required to color hydrangeas blue:
- an acidic soil with a pH value of 4 to a maximum of 4.5
- the permanent presence of aluminum ions in the soil
If your blue-flowering hydrangea takes on an undesirable color, action is required. If you don't take one of the following measures now, pink will play first fiddle from now on.
Tip:
An uncomplicated test from the garden center or hardware store provides clear transparency regarding the pH value. In order to correctly interpret the result, no prior knowledge of chemistry is required.
The best home remedies for coloring
It belongs in the realm of fables that rusty nails or copper coins can contribute to the blue color of a hydrangea. There is no denying that both ingredients increase the iron content of the soil and therefore act similarly to aluminum; Nevertheless, it will be the next or next generation of gardeners at the earliest who will be able to enjoy blue-colored hydrangeas. This is at least how long the oxidation takes. Coffee grounds lower the pH of the substrate, but not to the extent necessary. The best home remedies for coloring hydrangeas, on the other hand, have proven themselves well, work immediately and are inexpensive.
Alum
The natural remedy from the pharmacy has many uses in everyday life. As a surprising side effect, botanists discovered that potassium aluminum sulfate - alum for short - in the acidic soil makes the aluminum available for some varieties of hydrangeas, so that a blue color is possible. How to use the home remedy:
- Before starting to use, make sure the type of hydrangea is suitable
- In February, enrich the soil around the hydrangea with leaf mold, collected forest soil or acidic peat
- Additionally incorporate granulated cattle manure or compost
- Fertilize the ornamental shrub from March to July according to the normal care protocol
- Additionally, from March onwards, sprinkle 20 to 100 grams of alum around the hydrangea
- Repeat the administration of alum until the desired blue color occurs
From August onwards, fertilization will be stopped so that the farmer's hydrangeas mature before winter. With hydrangeas in a pot, the effect can be achieved more quickly and intensively due to the limited substrate volume. Using the procedure described, an existing blue color can be maintained and a desired color change can be initiated. At this point it should be noted again that a white hydrangea cannot be changed in color. Dark pink and deep red flowers take 1 to 2 years to turn blue, while cream and light pink varieties respond to treatment within one season.
Tip:
The effect of alum for coloring hydrangeas is further enhanced if the powder is dissolved in boiling water, with the addition of a splash of vinegar essence. The mixture must under no circumstances come into contact with the flowers and leaves.
lingerie blue
The traditional 'laundry blue' from the Ore Mountains has been reliably removing unsightly yellowing from laundry and curtains since the 19th century and making them shine in pure white again. The way it works is primarily based on the leveling of the lime in the washing water. In addition, the preparation contains 'ultramarine' as its central active ingredient, a mineral pigment group from which the world-famous 'lapis lazuli', one of the most brilliant blue pigments ever, comes from. The combination of the reduction in lime content and the development of ultramarine causes farmer's hydrangeas to turn blue. The effect of laundry blue is similar to aluminum sulfate and potassium alum. Unfortunately it is much more expensive, because 100 grams of laundry blue costs 4.90 euros, the same as 1000 grams of alum.
Commercial blue dyes for hydrangeas
In addition to the home remedies that can be used to dye hydrangeas blue, specialist retailers have various preparations available:
Cuxin hydrangea fertilizer with blue maker
As an organic-mineral NPK fertilizer, the product contains 500 grams of alum per 1 kilogram of granules. When used according to the instructions, Cuxin both initiates and permanently stabilizes the blue coloring of hydrangea flowers.
- Dosage: In March, 150 grams of fertilizer per square meter; another dose shortly before flowering
- Price: 1.5 kilograms from 8.90 euros
Garden paradise hydrangea fertilizer plus hydrangea blue
The product specifically focuses on turning hydrangeas blue. An extra bag of alum is included with the NPK complete fertilizer for this purpose. This prudence offers the advantage that hobby gardeners can selectively color suitable hydrangeas.
- Dosage: in spring and shortly before flowering 70 grams per plant
- Price: 1 kilogram from 8 euros
Norax hydrangea fertilizer 'gardener quality' with deep blue dye
This fairly high dosage of organic-mineral fertilizer is primarily aimed at producing magnificent flowers. Components such as horn shavings make a contribution to this. In addition, the preparation is enriched with alum.
- Dosage: one-time dose of 50-100 grams per ornamental shrub in spring
- Price: 1 kilogram from 8 euros
Manna Lin H blue hydrangea fertilizer
A practical liquid fertilizer for potted plants that turns the hydrangeas blue in the same go or stabilizes the blue color. Alum is responsible for the little color miracle.
- Dosage: One cap per 10 liters of irrigation water
- Price: 500 milliliters from 6 euros
It is important to note when using mineral and organo-mineral fertilizers that they should not be applied to dried substrate.
And vice versa?
Once you've had enough of your blue hydrangeas, simply perform the little magic trick in reverse. Now it’s time to raise the pH value of the soil – within tolerable limits, of course. Add a little algae lime or AZ activated lime to the soil and water with lime-containing tap water for a few weeks. The blue color will gradually disappear.
Conclusion
Hydrangeas offer the ambitious hobby gardener the fascinating opportunity to magically influence the color scheme. The varieties of garden and plate hydrangeas are capable of this miracle of nature. As a central requirement, the soil should have a pH value of 4 to 4.5. If a dose of alum or laundry blue is added, the chances are good that the colors will change from cream, pink or red to a rich blue. Aluminum sulfate or potassium alum develop their inspiring magic even more intensively when dissolved in boiling water with a splash of vinegar essence. This means that the best home remedies for coloring hydrangeas have already been exhausted, as the effect of rusty nails or copper coins is more than doubtful and coffee grounds are too weak. If you prefer a more convenient solution for dyeing your hydrangeas blue, choose one of the numerous products from specialist retailers.
