There are very few plants that you, the gardener, can actually choose the color that you want them to be in your garden. Hydrangeas happen to be one of them.
(Ye olde Behnke – E-newsletter horticultural editor can’t think of any others, by the way. If you know of any, email us at – contact us)
With some simple amendments to your soil, you can choose between making the blooms blue or pink. And while it doesn’t happen overnight, the magical blooms are well worth the wait!
The most important thing that influences the color of hydrangeas is soil pH-that’s the level of soil acidity. That means you may want to start with a soil test.
You can either get a soil test kit from Behnke’s, or you we can give you a kit to mail a soil sample in to the University of Delaware. In general, more acidity makes hydrangeas turn blue, less acidity (or more alkaline soil) promotes pink-that is, unless we’re talking about white hydrangeas, which alas, are limited to white.
5 Colorful Tips for Hydrangeas
1. Consider container gardening for hydrangeas as an easier way to control soil pH. Some of the newer varieties of hydrangeas feature huge flowers on compact plants which are ideal for containers.
2. Feeding hydrangeas well results in healthier plants with more saturated color. Espoma Holly-tone is an excellent choice for blue hydrangeas since it contains sulfur to lower pH. Espoma Plant-tone is ideal for feeding pink hydrangeas since it does not contain the additional sulfur.
3. Water hydrangeas steadily, especially in the hottest part of the summer to keep them from wilting. Mulch to keep roots cool and conserve moisture.
4. Hydrangea color can be affected by lime leaching out of concrete walkways or patios nearby, making blue a real challenge. Keep this in mind when considering where to plant. A word of caution: not all plants like acidic soil. Be careful about what’s growing near your hydrangeas.
5. One more tip from Behnke’s: if your hydrangeas are in an in-between color – say a mauve or taupe or purple that you don’t care for – then lowering the pH will get a nice true blue, or raising the pH will give a clear pink.
We hope this information about hydrangeas serves you well. Yes, changing soil pH takes a little time and effort, but the satisfaction it delivers will add beautiful color and variety to your hydrangeas – and your garden!