Hydrangea for Canadian Gardens
Hydrangea macrophylla is hardy to about zone 5 or 6 but in these zones, a cold winter can cause stem dieback along with a considerable reduction or even a complete loss of flowers for the season. This is because, up until recently, all bigleaf hydrangea cultivars were only capable of blooming on old wood. The loss of the previous season’s wood meant no flowers for the current season and a sad situation for an avid gardener dreaming of the glorious summer blooms.
New Breeding Innovations
But fear not, zone 5 gardeners! New breeding work has led to cultivars that bloom on both old and new wood guaranteeing that, even if a hard winter knocks back your stems (or an overexcited husband gets too ambitious with the pruning shears), you’ll still get flowers.
These cultivars are described as “blooming on both old and new wood” or as “reblooming hydrangea”. That’s because a cultivar that is not knocked back to the ground in the winter will at first produce blooms on the old wood at the start of the summer and then, as the season progresses, produce subsequent flushes of flowers on the new wood. When the old wood is lost in the winter, flowering will be delayed a bit further into summer until the new wood can be produced and come into bloom. But you’ll still get flowers.
Improved Varieties
This momentous advance has been accompanied by other great improvements to flower forms and colours including double flowers and bicolours, foliage colour including rich burgundy leaves, and dwarf forms great for small spaces or containers that only grow to about 3-4 feet tall and wide.
Even hardier are the smooth hydrangea, H. arborescens, and the panicle hydrangea, H. paniculata, both of which can withstand a zone 3 winter. These species bloom on new wood. H. arborescens is famous for its cultivar ‘Annabelle’ and the improved form, Incrediball, with huge white mopheads and stronger stems.
The panicle hydrangea has conical flower heads that emerge first in creamy white and age to pink and near red. New breeding work now offers us cultivars that change to glorious, deep, rich tones of pink as the flowers age.
Both of these super hardy species also have new dwarf forms perfect for small spaces and containers.
Other Interesting Species
Two other interesting species are the oakleaf hydrangea, H. quercifolia, and the mountain hydrangea, H. serrata, both of which are hardy to zone 5. The oakleaf also has creamy, conical-shaped flower heads and lovely, textured foliage that turns magnificent shades of red, orange, yellow and purple over a long period in the fall. The mountain hydrangea resembles the bigleaf hydrangea but is often a bit daintier usually with lacecap flower heads. It is also said that the mountain hydrangea is a bit tougher in colder climates like zone 5.
At Phoenix Perennials we often carry more than 100 different kinds of Hydrangea each season for our local and mail order customers. Come shop in person or order online for Canada-wide shipping!
Give Your Garden the Phoenix Perennials Touch:
At Phoenix Perennials we offer over 5000 different plants every year for in-person shopping at our garden centre and plant nursery in Richmond, British Columbia, part of Greater Vancouver. Additionally, we offer more than 3000 different plants each year for mail-order shipping across Canada. Stay connected with our diverse offerings and all things Phoenix Perennials by signing up for our E-Newsletter and Alerts and engaging with us on social media. Happy gardening!
