Source: Flickr user Ryutaro Koma
If you've ever admired a hydrangea bush blooming in all sorts of pastel shades, you'll be happy to know that the look is achieved by a simple science trick! You can actually change the color of your hydrangeas — making them pink, blue, or ethereal shades of periwinkle — by following these steps. Here's how to master the pastel rainbow effect:
Make Sure You Have the Right Type of Hydrangea
Only hydrangea macrophylla (aka mopheads and lacecaps) can actually change color, so make sure you buy the right kind.
Measure the Soil pH
It's easy — we promise! Use a soil test kit to figure out your soil pH levels. To get blue flowers, you'll want your soil to be acidic with pH levels of 5.5 or lower. For pink flowers, you'll want more alkaline soil with pH levels of 6.5 or higher. To achieve that pretty palette of blue, pink, and purple hues, get your soil to a pH level between 5.5 and 6.5.
Adjust the pH Levels of Your Soil to Get the Color You Want
Bailey's Color Me Blue (soil sulfur) or Bailey's Color Me Pink (garden lime) are great for adjusting pH levels, but you can also use a few homemade tricks, like using composted oak leaves, pine needles, or coffee grounds for blue flowers or wood ashes, lime, or fertilizers with high levels of phosphorus (a ratio of 25-10-10 is best) to prevent aluminum from entering the plant's system for pink flowers. This helpful guide will tell you how much additives to use for raising or lowering the pH levels.
Keep Treating Your Soil, and Be Patient
Continue treating the top layer of soil around the root area to keep the flowers in the desired shade. This process can take months, so be patient.