Once you have been gardening for a bit, a treasure chest opens up. Suddenly you realize that there are WAY more beautiful plants in the world that you ever thought possible. Tens of thousands of them. OK, so they won’t all fit into your garden, so what to do? A good approach is to look beyond the most common types of popular plants, and explore their relatives. These are often unique, interesting, easy to grow, and a great way to add variety and interest to your garden.
Take the hydrangea. For most people that means a plant with big, oval leaves and round, ‘mophead’ flowers. Part of the plant group called Hydrangea, often called hortensia, there are actually about 75 different species, and the plant you know well is just one of them.
That common mophead, Hydrangea macrophylla, is a native plant from Japan, it arrived in Europe centuries ago, and caused a big stir. So it became popular, and every nursery grew it. When settlers came to North America from Europe, some started nurseries, and they brought with them the plants they already knew. The industry grew up around these imports, and much of it today still focuses on these well-known species. Plants that grew wild in this new land were of interest to botanists and naturalists, but rarely to nursery growers. So nobody paid much attention to the native shrubs – indeed, they became popular first in Europe, especially in Britain, where they were ‘exotic’.
In the distant past North America and Asia were joined together, and when they split apart, groups of plants, like families, were separated. This is why we find many plant groups with species in China or Japan, and also with some in America. Hydrangea is like that, with 4 species growing here, and the rest in Asia. Of those four, three are felt by many to be so close they are treated as one, which leaves us with just two native hydrangeas. Let’s take a look at them.
It might come as a bit of a surprise to realize that this plant, so widely grown in colder states, is native to America. It looks a lot like a white mophead, although it can turn pink and red in early fall. Called Hydrangea arborescens, some people include in it two other species you might see mentioned – Hydrangea cinerea and Hydrangea radiata – considering them just variations.
This hydrangea grows wild all through the east, from New York state southwards. It can be large, up to 10 feet tall, but has small flower heads with tiny greenish-white flowers, and isn’t very attractive. It is seen in gardens as the older variety ‘Grandiflora’, or the newer variation on that, ‘Annabelle’. ‘Grandiflora’ was found growing wild in Ohio in the late 19th century, and has large, rounded flower heads of white flowers. Sometimes it is called ‘Hills-of-Snow’. The variety ‘Annabelle’, from The Gulf Stream Nursery in Watchapreague, Virginia, is similar, but with larger flower heads. It is very popular in colder parts of the country, and up in Canada, and here is why.
A Hydrangea for Cold Zones
The mophead hydrangea flowers at the ends of branches that grew the year before, so if those buds die in winter, no flowers. The smooth hydrangea flowers on new stems, around mid-summer, so it can be killed to the ground – as it often is in zone 4 – and still grow up and bloom prolifically. The heads can be a foot across, beginning as a soft, very light green with a lot of charm, then turning white. By late summer they begin to turn pink and often become very attractive shades of reds, before turning brown. This plant has a fault, though, because the large flower heads tend to bend over or break the relatively weak stems. Since this can mean staking many flowers, we no longer recommend growing these old varieties.
Instead, choose one of the newer varieties, created this century by some of our best breeders. For a big, sturdy replacement that is otherwise identical, consider the choice of Timothy Wood, from Spring Meadows Nursery, who discovered, among a big batch of seeds from ‘Annabelle’, the Incrediball® Hydrangea (‘Abetwo’). Standing 5 feet tall in warmer zones, and around 3 feet in colder ones, it has strong stems that hold up those heads with ease. See it at the left in the title picture.
Finally, if you want more color, we have that too. Consider growing the Invincibelle® Ruby Hydrangea (‘NCHA3’) from Thomas Ranney and his team, at North Carolina State. Flowering twice in warmer zones, it’s great. Or, for a lighter shade, go with the similar Pinkerella (‘Kolpinbel’) from Peter Kolster in The Netherlands. Both are true breakthroughs in bringing colored hydrangeas to gardeners in cold zones.
The Oak-leaf Hydrangea
We have one more species of hydrangea growing wild in North America. It is super-distinctive, and a fabulous shrub, even if you aren’t a hydrangea lover. The oak-leaf hydrangea, Hydrangea quercifolia, grows further south, from Georgia to Louisiana, so this is one that gives its best if you live in warmer places. It is, though, hardy in zone 5, but more sparing in blooms – still very worth-while for the spectacular foliage, though.
A large, rugged shrub it also has attractive reddish shredding bark that attracts attention in winter. The leaves are 6 to 8 inches long, and very distinctive, as they are divided into 5 lobes, like a giant oak leaf. Young leaves are fuzzy beige, turning deep green, with a dry, leathery texture. In most areas they turn stunning purples and deep reds in fall, although in zone 9 it is often semi-evergreen, only coloring in late winter. The flowers are huge, up to a foot long and 5 or 6 inches wide, carried on stems that come from older wood, often at the end of older branches. They are conical, reminiscent of the classic Pee-Gee Hydrangea, and a mix of small and large flowers, giving it a lighter look and always standing strong and upright.
Grow the oak-leaf hydrangea in semi-shade, like other hydrangeas, but also in sunnier places, as this is certainly the most drought-tolerant and heat-resistant of them all. Don’t prune except for removing weak or dead branches, and allow for it growing up to 8 feet across and 6 feet tall – a big, bold shrub for the corner of a bed, or in the angle of a building. If you do need to prune for size, do it in June or July, after the flowers have passed their best – that way it has time to mature stems for the next year.
Like the smooth hydrangea, this is primarily a white-flowering shrub, with probably the best all-round variety being Snow Queen™ (‘Flemygea’). This is a selection from the 1970s, but still holds its own. If it is too big for the spot you have in mind, then there is ‘Pee Wee’, around 3 feet tall, with smaller flower heads that are also denser white. Again, in recent years, pink flowering forms have been developed, such as ‘Munchkin’, another smaller form around 4 feet tall, with deep rose-pink blooms.
Now if you have lots of room, perhaps along the edge of a woodland, you can’t go wrong with ‘Alice’, a truly remarkable and vigorous variety that can, in time, stand 12 feet tall and wide, although usually it is a bit smaller. Selected by the most famous plantsman in America, Dr. Michael Dirr, who found it growing right on his own campus, the University of Georgia, he named it after his wife – sweet! It can be seen on the right in the title picture.
So don’t feel that you have to give up on native plants if you want to grow beautiful hydrangeas – you don’t. Just choose the right ones, and branch out into something different and beautiful for your garden.