Hydrangeas know how
Much sought-after flower a perfect fit almost anywhere
Hydrangeas are one of the most sought-after shrubs in North America.
Known for their nostalgia as well as their modern design appeal, hydrangeas are a perfect fit in the landscape, a container garden or used as cut flowers.
The National Garden Bureau has named 2020 the year of the Hydrangea and offers the following helpful tips and interesting facts about growing hydrangeas. I have tailored the information to benefit Niagara gardeners.
The word origin of hydrangea comes from the Greek words for water, hydros and jar, angos because some species are quite water thirsty. The hydrangea was first cultivated in Japan but they are native to both Asia and the Americas.
Selecting a hydrangea for your garden
When choosing a hydrangea, keep in mind these things: your growing hardiness zone, available space (they can get quite big!), soil makeup, moisture levels and amount of sunlight received per day.
More than 20 species of hydrangeas exist! Let’s take a look at four of the most popular varieties grown here in Niagara: Bigleaf (Hydrangea macrophylla):
The most common type in North America, bigleaf hydrangeas have the classic mophead — or open lacecap — bloom. With blooms of blue, pink, purple, and more, these classic hydrangea flowers bring colour to areas with morning sun, some afternoon shade, and moist, well-drained soil. Avoid planting Bigleaf hydrangea on hot, dry, exposed sites. The so-called ever-blooming hydrangeas, such as Endless Summer and Blushing Bride, should be treated the same. These bigleaf hydrangeas are unique in that they bloom on old wood and new wood.
Smooth (Hydrangea arborescens):
With a big, white (or sometimes pink) pompom bloom, these North American native hydrangeas are sometimes called ‘Annabelle,’ which is one of the most popular cultivar names. Perfect for full sun or dappled shade, the best flower shows are on plants that get six hours of morning light. The ideal location would offer a little shade in the hottest part of the day. Smooth hydrangeas are very hardy, blooms appear on new wood so there is no danger of the buds freezing during the winter. Newer (think larger, more plentiful flowers) from Proven Winners include: Incrediball (white) and Invincibelle Spirit (pink). Panicle (Hydrangea paniculata): Panicle hydrangeas (Peegee) have gorgeous coneshaped blooms that emerge white in mid-summer and age to various shades of lime, parchment, pink, and red as fall nights cool down. These hydrangeas are some of the most cold-hardy, many will survive up to zone 3, making this the perfect choice for colder climates. Panicle hydrangea’s upright form means it can be pruned into a tree form. Wellknown varieties include: Limelight, Pinky Winky, White Diamonds and Quick Fire. Oakleaf (Hydrangea quercifolia):
Aptly named, this hydrangea features leaves that resemble those of an oak tree. One of the earliest blooming species of hydrangea, this handsome shrub also takes on warm shades of bronze and burgundy in the autumn. Native to North America, we may be pushing the zone when planting Oakleaf hydrangeas here in Niagara. Buds form in the autumn and may suffer during extra cold winters. Bunnies will browse on the young twigs over the winter months, in fact, I lost an entire season of blooms to bunnies one year. Now, I protect the oakleaf hydrangeas by wrapping them with netting for the winter. Offer oakleaf hydrangeas a spot with several hours of sun to light shade and rich, welldrained, slightly acidic soils. Alice and Snowflake are popular varieties. Pruning your Hydrangea:
A popular question from readers: When should I prune my hydrangea? Pruning depends on the variety and when the buds are formed. Bigleaf (Hydrangea macrophylla) require very little pruning and bloom on growth from current and previous years, too much pruning removes potential blooms. Smooth (Hydrangea arborescens) bloom on “new wood” so they should be pruned in late winter or early spring. Cutting
the stems back to knee height will encourage strong, bushy growth. Panicle (Hydrangea panicula
ta) also bloom on “new wood” so they should be pruned in late winter or early spring to the ground or leave the stems 30 cm to 90 cm tall for taller plants.
Oakleaf (Hydrangea quercifolia) bloom on previous season’s growth so prune right after flowering if required — never prune oakleaf hydrangea in the spring — you will remove the flowering buds.
Pink or Blue Flowers?
Another common question about hydrangeas is how to get blue flowers. You can change a pink hydrangea flower to blue by changing your soil’s pH. (You cannot change the colour of white or green flowered varieties). If the flowers are pink, but you’d like blue, apply some granular aluminum sulphate to acidify the soil. Always follow package directions carefully. It may take several months or a season for it to work.
Uses in the Garden
Hydrangeas can be used in so many ways in your garden, from a focal point to establishing a border and filling the foundation around your house. Many hydrangeas, especially the newer varieties, are more compact and do incredibly well in a decorative pot. Hydrangeas make beautiful, long-lasting cut flowers, and they can be dried for winter arrangements. Tip: Plant container grown hydrangeas in a quiet spot in the garden for the winter, repot in the spring.