Getting mophead Hydrangeas to bloom

I finally cracked the secret for having lush blue or pink mophead hydrangeas in Zones 5 and 6 – and I’m not talking silk flowers. I had to downsize my expectations – not about size or number of flowers but the mature height of the hydrangea. So instead of varieties like ‘Endless Summer’ and ‘Nikko Blue’, I am opting for shorter specimens (3’ or less) like those in the Cityline (‘Venice’ pictured at right) or Let’s Dance series.

To understand my strategy, you need to know that mophead and lacecap Hydrangeas (in the macrophylla species) form their flower buds late summer or fall, the year before they are SUPPOSED to bloom (think Forsythia, Lilac, Rhododendron, Azalea). Unfortunately, in colder zones these flower buds are subject to being destroyed by bitter temperatures and winds. Bummer.

By electing for shorter shrubs, the flower buds are closer to the ground, more likely to be out of the path of strong winter winds. Plus if there is limited snowfall (snow is a great insulator), whatever snow there is will hopefully blanket the Hydrangea’s tender buds. I’ve thought about using rose cones (or similar protection devises) to put over the shrubs after they’ve gone dormant. (Hydrangea Let’s Dance ‘Starlight‘)
Another solution is to use dwarf hydrangeas as container plants. They look striking in large pots, surrounded by mounded and cascading annuals or perennials. When winter approaches, and the shrub has dropped all its leaves, give it a deep watering and then move it inside to an unheated garage, shed or barn. Then move it back outside in spring, after danger of hard frosts, and sit back to enjoy eye-popping blooms. Another bonus of growing them in containers is it’s easier to control the soil pH to get the color you prefer. (photo of hydrangeas grown in pots along the sidewalk to my front door)