Many gardeners in Northern climates have been enjoying the blue hydrangea 'Endless Summer' for a few years. Unlike most mophead hydrangeas (Hydrangea macrophylla), 'Endless Summer' blooms on new and old wood, so even if it dies back in winter, it still produces a flower show the next summer.
Now a new series of hardy hydrangeas is available that expands the color choices. The Forever & Ever hydrangeas also bloom on new and old wood, they are compact growers, and they produce large flowers.
Forever & Ever Red (H. macrophylla 'Red Sensation') grows 3 feet tall and wide and produces large, round flowers in midsummer that start out red and fade to purple. It's hardy to USDA zone 4. Forever & Ever 'Double Pink' (H. macrophylla 'RE109') has the same growth habit, but it produces double pink or blue flowers, depending on the soil pH. It's hardy to USDA zone 5.