The mophead hydrangea is such a constant feature in gardens of warmer climates, and it has been around for so long, you probably never asked where it first came from. It’s iconic colors of pinks and white, and especially the sought-after blues, make it the plant most people think of when asked to picture a hydrangea, even though it is just one of several different types. Once commonly called ‘hortensia’, still it’s name in much of Europe, to botanists this plant is Hydrangea macrophylla, meaning ‘bigleaf’. For most of us, though, while certainly admiring the leaves, it’s the big flower heads that catch our attention, and their full, blowsy nature is why they carry the name ‘mophead’. If only mops were as beautiful!
It was those big heads that must have caught the attention of the first western plant-collectors too, not while trekking through the jungle somewhere, but while being shown the plants at a well-organized nursery in Japan. That fact received little attention at first, but the plants quickly become a craze once they arrived in Europe. Let’s explore this story in more detail.
Peter Thunberg and Mophead Hydrangea
Carl Peter Thunberg was a young Swedish botanist, a student of the famous Carl Linnaeus, the creator of our modern plant naming system. Ambitious, he leveraged his training as a doctor to take a post in Japan, at the time a closed country, and foreigners were tightly controlled and confined to a small island which was virtually a prison. Thunberg traded his medical skills, which the Japanese admired, for access to plants, and in 1784 published the first account of the plants of Japan. He included a description and picture of a hydrangea, (which he mistakenly called a Viburnum). The plant he showed wasn’t a wild plant, as it was a mophead, which we now know is not the wild species.
Thunberg’s plant, which might have been brought to him by Japanese assistants, must have come from a nursery. Japanese people had gardened for thousands of years, and nursery production was well-developed. Thunberg’s plant was a variety we today call ‘Otaksa’. It was rare in Japan, and had in fact been selected in China, where the Japanese wild hydrangea was a popular plant.
Joseph Banks and Hydrangea
Of course a picture in a book is not a live plant, and the first growing plants in Europe came not from Thunberg, but from the famous English botanist, Joseph Banks.
Thunberg and Banks had a complex relationship, and for a little-known story of how their paths crossed over the Breadfruit Tree, see this blog.
Around 1788 Banks found the same plant, but in a slightly different variety, in China, brought it back to England and gave it the Kew Gardens, already famous for its rare plants. When they first flowered it gardeners were astounded, and within a few years it was being widely grown across England.
Now named ‘Sir Joseph Banks’, that variety can still be found in specialist collections, as can Thunberg’s ‘Otaksa’. It seems to have been Thunberg’s plant which arrived first in Europe, since he had connections with botanic gardens there. Both are large, full bushes, over 6 feet tall and wide, with good sized heads, and both show something else that makes mophead hydrangeas special – their ability to change from pink to blue depending on the acid or alkaline character of the soil.
Other Early Collectors of Hydrangea
The popularity of those first plants send ‘hydrangea’ to the top of the list for other collectors seeking fame, and they responded by bringing back more, from both Japan and China. The German Philipp Franz von Siebold, another doctor and botanist, succeed in entering Japan in 1823 and brought back many plants to Europe in 1829. Due to wars he had to leave most of them in the Netherlands, at the botanical gardens in Ghent, rather than bring them home to Germany. It’s worth noting that Siebold’s collections arriving in that country help it to become the European capital of horticulture it still is today. Among Siebold’s plants was also the very different climbing hydrangea, Hydrangea petiolaris, a beautiful self-supporting climber for an east or north-facing surface.
In 1860 the Tsar of Russian sent the botanist Carl Johann Maximowicz to Japan, and he returned with around 400 plants, including many hydrangea, that were grown at the royal palaces in St. Petersburg.
Then, in 1879 that the collector Charles Maries was sent to China and Japan by the great English nursery of Veitch. While others had concentrated on mophead types, Maries returned with the first lacecap type, Hydrangea macrophylla ‘Mariesii’. These plants have flat flower heads, with a circle of larger flowers surrounding a fluffy center. They are wonderful, under-used garden plants, free of problems like breaking and collapsing in storms.
From Pot Plants to Garden Shrubs
At first the mophead hydrangea was grown as a pot plant, and remains almost as popular today as it was then. Using all the material brought over by these, and other, collectors, new varieties were developed through the 19th century, in all shades of pinks, blues and whites. Because they started with different original plants, Europe and England continue to have their ‘own’ popular varieties, with plants arriving in America from both sources.
When planted in gardens, though, these potted varieties are not always suitable. They have been bred to be small, and not all are particularly hardy. They respond to the precise conditions of a greenhouse, and don’t always perform well in the garden. Of course people continue to plant out a bush they bought in bloom, but for gardens it is best to choose varieties especially developed for outdoor growing.
Finding the Wild Hydrangea
All this development revolved around those early garden varieties, but what about the original, wild plant? It was only in 1917 that it came to the attention of western botanists. The collector Ernest Wilson, famous for collecting in China for the Arnold Arboretum at Harvard, and for England’s Veitch’s nursery, brought back plants from the wild, which became known as Hydrangea macrophylla var. normalis. This is a large shrub that can reach 10 feet tall, found crossing in coastal areas on the Chiba peninsula south-east of Tokyo and on islands south of Tokyo. Called the Japanese maritime hydrangea, it explains why garden hydrangeas do so well in coastal gardens.
Today, the closest plant available to the wild plant is a variety called ‘Sea Foam’, which is actually a reversion from ‘Sir James Banks’. In other words, the original wild plant re-appeared on a bush of the mutated double form – a kind of ‘re-wilding’ if you wish. See the picture heading this blog for a plant of ‘Sea Foam’ in its glory.
From this plant were created all the variety of colors and shapes of today’s mophead hydrangeas. Of course, all that depended on the original double varieties found in China and Japan. Of their origins – the when, where and who – we know nothing, but it does seem to have been the Chinese, not the Japanese, who started it. Not so different from how American breeders have taken relatively humble plants from both Europe and Asia to create some of our most beautiful garden plants.
The Future of the Mophead Hydrangea
The reason why so many people are frustrated with growing mophead hydrangea comes from the way this plant naturally only flowers at the ends of older branches. Winter cold can easily kill the flower buds, and the result is no flowers. It was only in 1998 that the legendary Dr Michael A. Dirr was visiting a nursery in Minnesota. There he saw a branch on a plant flowering later in summer – a very unusual thing.
That branch became the first repeat-flowering hydrangea, Endless Summer (‘Bailmer’) and brought mophead hydrangeas in reach of gardeners in zone 4, and made them repeat-flowering in warmer zones. Since then there have been numerous other repeat-flowering varieties, all of which can flower in the new stems made each spring. The promise they bring remains uncertain though, with variable results, and even with them cold-region gardeners cannot achieve the big, flower-laden bushes of the South. Still, you can have fun and in a good year a reasonable display on a smaller bush – a worthwhile thing for any keen gardener to enjoy.