The undemanding hydrangea

Delicate, oblong flower heads of Hydrangea paniculata ‘Little Lamb’ start out as whitish with a blush of pink in mid-summer and then turn pink by fall. This photo was taken last fall in the Winnie the Pig area at the Community Education Garden along Western Avenue in Wenatchee. This hydrangea blooms on new wood.

Hydrangeas are an old-fashioned flowering shrub with ample reason for remaining popular with gardeners. They offer tremendous bouquets of flowers on a non-demanding, deciduous bush.

Most hydrangeas are impressive and easy to grow, happy in our climate with morning sun, afternoon shade, regular water and good soil. Some take severe cold better than others. Many can reach 8-feet tall or higher, although there are plenty of more compact beauties. Most are native to Asia and a few to the Eastern United States.

Called mopheads, the old types (Hydrangea macrophylla) sport huge balls of blue or pink sterile flowers. They were a mainstay of older gardens and deservedly remain a favorite. Blue flowers are produced in acid soils (a pH of 5.5 or lower), while alkaline soil results in pink or reddish blooms. If you prefer blue, apply aluminum sulfate to soil and be patient, as it takes time for changing the pH of soil. Add lime or superphosphate for more pinkish coloring.

There are some varieties in this H. macrophylla group with lacecap flowers, such as Blue Wave, a favorite of my daughter’s. She likes the structure of this broad shrub as well as its beautiful flowers.

Lacecap types display beautiful flower clusters with centers of closely bunched, tiny fertile flowers surrounded by large, open sterile flowers. They are a bouquet of flowers on a single stem! Another lacecap is H. serrata, which will take more sun but still needs afternoon shade.

Oakleaf types offer more interesting lobed leaves (H. quercifolia), turning bronze or crimson come fall. They take cold in stride and produce oval or elongated clusters of flowers rather than rounded bouquets.

These are just a few of the many varieties of hydrangeas.

And now the big question: To prune or not to prune? It depends on the variety you have and whether it seems to be losing vigor, producing less flowers or has some tall, floppy branches needing a trim.

Ones that bloom on old wood, (many of the H. macrophyllas, the oakleaf types and H. paniculata) do it just after flowers are fading and before new growth starts.

Sometimes to reinvigorate growth, you might want to cut a few of the older stems right down at ground level.

Those that produce flowers on new wood may be trimmed right down to the ground in late winter before new growth begins. These include H. paniculata and H. arborescens. These shrubs usually bloom later than the others.

If you are searching for an undemanding, flowering shrub for a somewhat shady area, do some research on the many types and sizes of hydrangeas.

A WSU Master Gardeners of Chelan County column appears weekly in The Wenatchee World. Mary Fran McClure is one of four columnists featured. To learn more, visit wwrld.us/cdmg or call 667-6540.