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Hydrangea Color Change | From Pink To Blue

You bought those blue hydrangeas you have always wanted, planted them, and the following year they bloomed, big beautiful...pink flowers. Ugh! Why did this happen? Where did your BLUE flowers go? Can you get them back with the process of hydrangea color change? Yes...if you’re patient.

It can take weeks or even months to years to adjust the soil pH and therefore adjust the color of your hydrangea plants. Generally it is more difficult to change pink hydrangea flowers blue that it is change blue flowers pink. So you blue lovers may require a bit more patience and dedication. Check out the huge selection of hydrangeas at our plant
nursery!

Step One

Check your soil pH to know where you stand. The optimal pH for blue blooms is 4.5 to 5.5. If your pH is higher than 7.5 this may be a fight you won’t win. Soil this high in pH tends to have free calcium carbonate or marl which make it very difficult to lower the pH.

Turning you hydrangea flowers blue can be as simple as applying aluminum sulfate, elemental sulfur or our Espoma organic soil acidifier. Aluminum sulfate is a chemical compound that reduces the pH of your soil. Elemental sulfur is pure sulfur which is an element that acidifies your soil. You know - the periodic table from high school science class - yep, those elements. Both aluminum sulfate and elemental sulfur work by making aluminum available to your hydrangeas. This reaction acidifies the soil and your plant produces blue flowers. Elemental sulfur is the cheaper choice, but aluminum sulfate works faster so it is usually the preferred choice for most gardeners.

Step Two

For established plants apply 1lb (2 cups) of aluminum sulfate or 1/6lb (1/3c) elemental sulfur around your hydrangea bush. Be sure to check the directions on the package you choose as there can be variations in products and directions. A direct topdress to the soil around your hydrangea plant covering the entire rootzone out to the dripline seems to be the most effective and easiest method versus a water dilution.The optimal time to apply the initial dose is late winter or early spring.

Step Three

Water the sulfur in well. This is the key to getting the chemical processes going so don’t skip this step! Be sure to rinse off any sulfur that got on your plant.

Step Four

In about 3 months check your soil pH again. Hopefully you will see your soil pH in the appropriate range, but if not repeat the application again until you reach the desired acidity. If you are seeing purple hydrangea flowers instead of pink flowers you are on the right path and can just apply another dose.

Blue Boosters - Tips from the Pros

Mulching with pine straw or pine bark or adding peat moss or compost to the soil are other options for acidifying your soil over time and help out with general hydrangea care as well. These tactics are helpful but take much longer than applying sulfur because they must break down which takes time. However these options may mean less work next year when combining them with the application of aluminum sulfate or elemental sulfur to your blue hydrangea (fingers crossed) this year.
 
Hand watering may affect your efforts especially if you have hard water. Hard water tends to be high in pH or alkaline. A good solution if you have hard water is to catch rainwater and use that to water your hydrangeas.
 
Avoid planting your hydrangeas near concrete foundations or sidewalks. These structures often contain lime that leaches out into the soil. Soil pH near these structures can be raised considerably.

If you have tried everything with no success, you can always grow your hydrangeas in pots. This controlled environment is an easy way to get your flowers the color your want. To adjust the pH of the potting medium cut the sulfur dose in half for container grown hydrangea bushes.

Check out the Hydrangeas types today from our online plant nursery and have them delivered to your doorstep!

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