
Hydrangea
A valuable genus grown for their large and very showy flower heads, Hydrangeas are at their best in summer and fall—a quiet time for most woody plants—and these shrubs are worth having for that reason alone. Fortunately for gardeners in colder zones, recent introductions are more likely to flower on new growth as well as year-old stems.
Some varieties of Hydrangea change flower color depending on the pH of the soil, generally blue on acid soils and pink on alkaline. With these varieties, you can change the color of your blooms by using one of the soil additives available here.