Last updated on August 1st, 2019
One of the best things about hydrangeas is that you can, with mophead and lacecap varieties, alter their color. You can choose to have beautiful pink blooms even if your hydrangea naturally produced blue blooms last season.
How to make hydrangeas flower pink
Turning hydrangeas blue to pink is as simple as changing the soil composition in your garden. There are, however, some points to consider:
- Whatever you do to change the soil composition will need to be done regularly in order to maintain the results. If, for example, your plants produced blue blooms last season and you want pink this season, then any subsequent year where pink is desired will require the same soil changes otherwise the flowers will naturally go back to blue.
- It is important to understand that because the chemistry of your soil can actually change the color of the blooms, the names of your mophead or lacecap varieties doesn’t really mean much so if you see a name like forever pink, that doesn’t guarantee that the flowers will be pink. The same is true of something like Pretty in Pink. Each type, whether the name has the word blue or the word pink in it has an equal chance of blooming in a blue or pink color depending on the soil in which they are planted.
- To that end when you purchase a hydrangea from a nursery it might already be in bloom and you might notice that the flowers are bright pink or bright blue but that does not mean that once it makes its way into your garden it will maintain that same color. It is only producing the color you see in the nursery because of the alkalinity or acidity of the nursery soil. Once you take it back to your home and plant it in your garden, the soil will likely be very different.
It is significantly easier to cultivate fabulously pink hydrangeas simply because while you can change the soil conditions in favor of blue or pink color, if you naturally have a very high alkaline soil content it will be very challenging to get the blue flowers you want regardless of how much aluminum you put in the soil. Highly alkaline soil will typically lock up any aluminum present which means you can add all the aluminum in the world but it won’t ever make its way into the plant. So anyone looking to cultivate pink hydrangeas is in luck.
What soil do you need to turn hydrangeas pink
In order to change the soil PH, you want to test the area where you intend to plant your hydrangea first. This will give you a baseline. From there you can test the soil annually to make sure that you are maintaining the pH level that you want. It might take time so this could be something that you prepare for prior to purchasing our poor transplanting a hydrangea just so that you can monitor the changes to the pH until it reaches the appropriate point.
In order to change the soil for pink blooms you can add powdered garden lime. This should be applied in the fall because it can take several months for the soil to change. Dolomitic limestone is another option as it increases magnesium in the soil.
Gardeners can add wood ash which works much faster than limestone because it adds trace elements like potassium to the soil however, adding too much can cause nutrient imbalances so you need to be careful. For best results add this in the winter and do not add more than 2 lbs per 100 square feet every two or three seasons.
No matter what you add, if it comes from a store be sure to follow the directions printed on the labels.
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