Flower of the Week: Hydrangeas

Many people remember hydrangeas from their childhood. Today we are falling in love with them all over again—the good news is, we can grow many hydrangeas our grandmothers never dreamed of.

The following post was submitted by staff member, Maggie Wiles. 

This shade-loving beauty offers huge bouquets of clustered flowers, in various arrangements from mophead to lacecap, from summer through fall. Varieties differ in size of plant and flower panicle, flower color, and blooming time. 

Hydrangea macrophylla is by far the most widely grown with over 600 named cultivars, many selected to have only large sterile flowers in the flowerheads … often referred to as mopheads. Flowers can be blue, red, pink, light purple, or dark purple depending on the pH of the soil.

If you're seeking blue flowers, check your soil's pH level and apply aluminum sulfate in spring to lower pH to the 5.2-5.5 range. The change in flower color results from lower pH and higher aluminum content in the soil.

In the past Hydrangeas bloomed on either new or old wood, thereby flowering early in the season or later. Now, there are several new collections, the Endless Summer Series and the Forever and Ever varieties, that have extended the blooming season from early summer to fall by producing bloom on both old and new wood.

Hydrangeas thrive in a moist, fertile, well-drained soil in partial to full shade.  All hydrangeas need sun to produce their flowers, but will wilt in the hot afternoon sun.

The bold texture of their foliage and their prolonged season of bloom makes hydrangeas ideal shrubs for a summer garden. The flowers and foliage age gracefully, too, taking on rosy tints that make them one of the great, if melancholy pleasures of autumn.