Hues so blue, your yard will be the talk of the neighborhood. Coffee grounds can be used to make hydrangea blooms bluer by increasing soil acidity. The intensity of a hydrangea's blue color depends on ...

Hydrangea macrophylla (Bigleaf Hydrangea): This variety is most commonly affected by soil pH. It includes both Mophead and Lacecap types. The color change is most dramatic in these hydrangeas.

Anyone who has picked up an instructional gardening book has gleaned that it might be important to test your soil’s pH before embarking on any major planting project—but too often gardeners skip this ...