Did You Know You Can Change Hydrangea Colors from Pink or Blue?
The methods used to change the color of hydrangea flowers really illustrates the importance of knowing your garden soil profile and having the proper organic matter and nutrients for your garden plants.
Hydrangeas may produce pink, blue, or lavender blooms, depending on where they are planted and how they're fed. The presence of aluminum in the plant ultimately determines the color, and pH affects the uptake of aluminum. Alkaline soils, pH of 6.0 or more, are more likely to produce pink blooms, and more acidic soils, pH 4.5 to 5.5, produce blue flowers.
Pink hydrangeas can be turned blue by applying aluminum sulfate to lower the pH and add aluminum to the soil. Applying lime to raise the pH level will help blue hydrangeas turn pink. If your soil naturally produces very blue or very pink hydrangea flowers, you may need to grow your hydrangeas in containers or raised beds to achieve the desired color. If you do attempt to change the color of your blooms by adding these minerals, dilute them well, and add sparingly. It is very easy to scorch your plants by adding too much. White hydrangeas are not affected by efforts to change bloom color.
Steps for Changing Hydrangea Colors
Bigleaf hydrangeas, especially lacecap and mophead (Hydrangea macrophyllis) change color. If you’re experimenting with changing hydrangea color, amend the soil in late fall or early spring before flowering.
pH Levels
The pH levels needed for adjusting your soil to affect the bloom color are as follows:
- Blue hydrangeas: soil pH 5.0 to 5.5
- Pink/purple hydrangeas: soil pH 6.0 to 6.5
Step 1
Step 2
Pink flowers: To turn your hydrangea flowers pink add lime to your soil. Sandy soils require less lime than clay soils. In general, applying approximately one cup of lime per hydrangea plant once per year is safe. Staying within the drip line, sprinkle the lime around your plant’s soil. Combine the lime with the top layer of soil. Gently turn only this top soil level with a rake or trowel to avoid harming your plant’s roots.
Blue Flowers: To turn your hydrangea flowers blue, add Espoma Organic Soil Acidifier around your hydrangea bush. Be sure to check the directions on the package because there may be variations in products and directions. In late winter or early spring, sprinkle acifier within the hydrangea plant’s dripline covering the entire rootzone.
Step 3
Tamp down the soil to ensure the amendment incorporates. Water deeply and thoroughly. If you’ve accidently sprinkled the leaves with the lime or acidifier, be sure to rinse it off the plant.
Step 4
Test your soil after a few months. If the color change hasn’t happened yet apply another dose of lime or sulfur depending on the result you’re aiming to achieve: more lime if you want pink flowers, more sulfur acidifier for blue hydrangea flowers.
