Hardy hydrangea can test your impatiens
Time was, only a few years ago, that the most reliable source of colour in a garden were impatiens. Many readers will recall drifts of the blooms in vibrant ice cream colours everywhere — from home garden borders, to city lots, parks and in containers on cottage docks.
Impatiens created an addiction to reliable blooms that had not been matched before or since. Then downy mildew entered the picture and bam! Impatiens collapsed across North America.
Plant hybridizers have been racing to find a mildew-resistant strain of impatiens and are said to be close. But in the meantime, our predilection for colour has moved to the winter hardy, plant-once-and-done, ever-expanding family of hydrangeas.
In the current issue of the Sheridan Nurseries guide, considered to be the “bible” of nursery catalogues, there are no less than 44 varieties of hydrangea listed. There are five families or species of hydrangea widely available, each with unique characteristics. Here is our primer for the uninitiated. á Arborescens. Native (originally, before they were hybridized), and sometimes called smooth hydrangea, which includes the historically popular, globe-shaped Annabelle flowering shrubs. Winter hardy even on the Prairies, these plants mature to about 1- ⁄2 1 metres high and around. They bloom in July and through the summer, especially the new varieties.
Our favourite is Incrediball — the flower is about the size of your head. They’re easy to grow but require sun for at least six hours a day. Prune them back by at least a third in the spring. Annabelle performs best when cut down to within six centimetres of the ground, otherwise they grow to become top heavy and fall over in a rain. á Macrophylla. Native to Japan, these plants better known by their commercial name, Endless Summer, were introduced about a generation ago. This family of hydrangea include the popular lacecap flowering varieties.
Our favourite is the new Summer Crush Endless Summer, which can be blue or red, depending on the acidity of the soil (acidic soil encourages blue, alkaline for red). This variety blooms on old and new wood, so it is hard to go wrong with pruning. á Serrata. Native to Japan, this one is hardy to zone 5 (south of Barrie). Serrata hydrangeas require little pruning as they bloom on old wood. Most varieties feature blue or pink blossoms, again depending on soil acidity. á Quercifolia. This less winter-hardy family features the popular oakleaf hydrangeas. We have not had a lot of luck with it in our own zone 5 gardens, but they thrive in gardens in Toronto and along Lake Ontario. There are some wonderful specimens of quercifolia at the Royal Botanical Gardens, on the Hamilton-Burlington border, where they are frequently used as the feature plant in a large perennial bed.
These are native to the Carolinian forest here in Ontario. Prune just after the blossoms finish.
> Paniculata. Native to Japan and China, this family features the popular Limelight hydrangea, a reliable perennial flowering plant that grows up to three metres high, and wide, if not controlled. This family is named for their panicle, or lilac-like cluster of flowers.
All paniculate varieties lend themselves to pruning and we recommend a light pruning each spring. Also worth a look is Pinky Winky (who comes up with these names?) with mammoth, two-toned blossoms up to 50 cm long (pink base with white tips). Most panicle varieties feature white or cream flowers mid- to late-summer and early fall.
All hydrangeas are relatively disease- and insect-free, some are more winter-hardy than others (check your favourite varieties against your growing zone) and all of them lend themselves to being cut for indoor bouquets.
To dry them for permanent use indoors, place the cut flower stem in two cm of water and allow the water to evaporate. As the stem and flower slowly dry, the flowerets will remain in place, though the vibrance of the original colour will fade a bit.
In truth, there really is no substitute for impatiens and when the new, disease resistant varieties are widely available and proven performers, we will let you know. In the meantime, hydrangeas are stars in most any garden.