To keep purple hydrangeas purple, it’s important to maintain the soil pH within a specific range. Hydrangeas are unique in that their flower color can be influenced by the acidity or alkalinity of the soil they are grown in. Acidic soil, with a pH lower than 6.0, tends to yield blue or lavender-blue hydrangea blooms. On the other hand, alkaline soil, with a pH above 7.0, promotes pinks and reds. A pH between 6 and 7 results in purple or bluish-pink blooms.
One method to keep hydrangeas purple is by adjusting the soil pH. If your soil is naturally alkaline and you want to maintain purple blooms, you can add amendments to lower the pH. One commonly used amendment is garden sulfur. It can be applied according to the package instructions to gradually lower the pH over time. Another option is aluminum sulfate, which can also be used to acidify the soil. However, it’s important to follow the recommended application rates to avoid over-acidifying the soil.
When adjusting the pH, it’s essential to regularly test the soil to ensure you’re within the desired range. Soil testing kits can be purchased at garden centers or through online retailers. These kits provide detailed instructions on how to collect soil samples and measure the pH accurately. By monitoring the pH levels, you can make necessary adjustments to maintain the desired purple color in your hydrangeas.
It’s worth mentioning that soil composition and organic matter content can also influence pH and affect the availability of nutrients for the plants. Adding organic matter, such as compost or well-rotted manure, can help improve soil fertility and structure. Organic matter acts as a buffer, helping to maintain a stable pH range. Additionally, it enhances the overall health of the soil, promoting better nutrient absorption by the plants.
In my personal experience, I had a hydrangea plant that initially produced beautiful purple blooms. However, over time, the color started to fade to a more pinkish hue. After conducting a soil test, I discovered that the pH had risen above 7.0, indicating alkaline soil conditions. To bring back the purple color, I added garden sulfur according to the recommended dosage. Over the course of a few months, the pH gradually decreased, and the hydrangea began producing purple blooms again.
To summarize, maintaining purple hydrangeas involves ensuring the soil pH remains in the appropriate range. Acidic soil with a pH lower than 6.0 promotes blue or lavender-blue blooms, while alkaline soil with a pH above 7.0 encourages pinks and reds. To keep hydrangeas purple, you can lower the pH by using garden sulfur or aluminum sulfate, following the recommended application rates. Regular soil testing and the addition of organic matter can also help maintain a stable pH and provide optimal growing conditions for your hydrangeas.
