This traditional favorite is a must-have in any garden, and new cultivars have made hydrangea cultivation simpler than ever.
Generally speaking, blue or lavender-blue hydrangea flowers are produced by acidic soil, which has a pH lower than 6.0. Pinks and reds are encouraged by alkaline soil, which has a pH above 7.0. The blossoms turn purple or bluish-pink at a pH of 6 to 7.
Add aluminum sulfate or garden sulfur to your soil to reduce pH levels. Use ground lime to increase the pH. To ensure that the pH of your soil is within the desired range, retest it according to the instructions on the product you’re using.
How are blue or purple hydrangeas maintained?
Although most plants may grow in a variety of soils, others require particular kinds of soil to thrive. Rhododendrons, azaleas, and other ericaceous plants require acidic soils in order to thrive. The soil in your garden must be acidic if they flourish there or in the gardens nearby. Rhododendron leaves turning yellow or disappearing from the area indicate that your soil is likely alkaline. In addition to affecting what you may grow, your soil type can also affect some plants’ leaf and blossom colors; hydrangeas are a well-known example.
Some hydrangea cultivars grow pink or red in alkaline soil and blue or purple in acidic soil. Therefore, if you plant a beautiful blue lacecap or mophead hydrangea in your garden and your soil is neutral to acidic, it will continue to produce blue flowers every year. Even if it was clear blue when you got it, it will flower purple-red or pink if you plant it in alkaline soil the next year.
It is challenging to keep beautiful blue blossoms alive in the open ground, but it is doable if you grow it in a pot; hydrangeas make wonderful topics for pots and containers. Select a pot that is attractive and big, at least 40 cm (15 cm) in diameter. Vitax Ericaceous Compost is the best growing medium for it; plant it there. If you consistently feed your hydrangea, it will thrive on this fertilizer that is specifically made for rhododendrons, azaleas, and other lime-hating plants.
Even though the growing medium begins out being free of lime, repeated watering in places with hard water tends to make it more alkaline. Therefore, add Vitax Hydrangea Colourant, a powder containing aluminum that you may mix with the compost, to ensure that your hydrangea stays truly blue. Each spring, you can also incorporate a small amount into the soil’s top layer and add it to the can when watering your plant.
White hydrangeas, incidentally, don’t change color depending on the type of soil, but they can blush pink in the light.
Feeding and watering
In pots, containers, and during dry spells in the open ground, regular watering is necessary since hydrangeas detest dry environments. When you plant your hydrangea in a bed or border, add lots of garden compost or farmyard manure, and make sure to water well both before and after planting.
The presence of food in the soil is necessary for hydrangeas to grow and produce flowers, even if they are not very demanding plants. In the open ground and in pots and containers, Vitax Conifer and Shrub Fertilizer should be used annually. This is ideal for acid-loving plants and won’t change the hydrangea’s color.
What should the soil include to preserve the hydrangeas purple?
Grow your plant in its current soil for a year to allow it to reveal its “true colors.” If the blossoms are a deep blue color, your soil likely contains aluminum and is acidic. Simply adding lime and phosphate to the soil will result in purple flowers. By doing this in the fall, you can change the colors for the upcoming growing season. Make a note of how much lime you used so you can later change the colour to your preference.
If the blossoms are pink, test the soil to find out how much aluminum is present and the pH of the soil. If there is a lot of metal in the soil but a high pH, add organic compost to lower the pH. The color will shift toward blue as a result.
It makes no difference whether the pH is high or low if the soil lacks aluminum because the process for altering bloom color is the same. The soil has to be amended with aluminum sulfate. Aluminum is also added as the soil is acidified. Over multiple growing seasons, you’ll need to experiment with the amount you administer to bring the blossoms to your desired shade of purple.
How can you maintain the various hues of hydrangeas?
Your blue hydrangeas’ color can be greatly improved by adding a small amount of aluminum sulfate. According to Myers, “the acidity of aluminum is what impacts the blue color of flowers.” “To brighten the blues of your flowers, consider adding aluminum sulfate or an equally acidic element like ammonium sulfate to the soil in alkaline soil, where there isn’t as much aluminum available to the plant.”
My purple hydrangeas are turning white; why?
We are frequently questioned as to why hydrangea flowers lose their beauty quickly and only last a short while. There are a variety of causes for this, but usually it’s just the plant and the blooms developing naturally. The flowers aren’t doing as well as they should, but there are a few causes for this.
- Stressed out hydrangea plant. The plant frequently receives either too little or too much water. Another possibility is that the plant is not receiving enough sunshine.
- The dirt is a challenge. Either the soil’s nutrients have been depleted, or the pH is overly alkaline or acidic. Most frequently, the plant just requires some fertilizer because the nutrients are the issue.
- The plant is under stress due to bugs. This also illustrates the initial problem. However, this is less frequent than the issue being caused by sunlight or water.
The issue is most frequently either too much afternoon bright sunshine or a lack of water. Mulch application will assist keep the soil moist and safeguard the roots. In some instances, watering using a soaker hose can be a major help in preventing hot summer afternoons. Before attempting to solve any of the other issues stated, make sure that neither of those two possibilities is the issue.
Additionally, the blossoms of some hydrangea species last longer than those of others. White-flowered hydrangeas frequently have blossoms that start out white, then change to pink, and finally deep red. These will endure longer than flowers that are blue, purple, or pink at the beginning.
In summary, the following are the most typical causes of hydrangea blossoms fading:
- the afternoon sun is too direct.
- inadequate water
- Stress brought on by pests
- The hydrangea requires fertilizer.
- The flower’s normal development