Sandy’s Garden ... Charles Darwin and the Tulip

Sandy Simpson
Sandy Simpson

I suspect that there is not a single reader who has not heard of Charles Darwin.

At the age of 50 and in the year 1859, Darwin published his magnum opus, ‘The Origin of the Species.’ This book challenged many of the beliefs of his generation, and of all preceding generations, about how mankind came to be and of how the universe … together with all its multitudinous ramifications … was created. Even today there is much about Darwin’s theories which remains to be clarified; and even today there are those who deny the truth of Darwin’s assertions that every species in the world has evolved over innumerable generations through a process of natural selection which allows the strongest to survive. He was ridiculed in many quarters for suggesting that mankind and the other primates were closely related, as he was for advancing his theory that all forms of life had a common origin at some time in the past.

Nowadays, the scientific world accepts Darwin’s theories and seeks constantly to deepen our knowledge and understanding of them; and nowadays Darwin’s name is accorded the respect which his brilliance deserves. And it may well be that the gardener who has recently planted tulip bulbs has seen his name in connection with them, for most tulip bulbs today are, botanically, described as ‘Darwin hybrids.’

To understand the origin of this term we must remember that, in past years, plants were often named after famous plant collectors, or nurserymen, or famous figures in the world of natural science. It was scarcely surprising that one of the larger species of tulip being developed by nurserymen … Tulipa, in botanical terms … was named after Darwin as a means of identifying it as distinct from its many cousins. So Tulipa Darwinii entered the vocabulary of the botanist. Then plantsmen crossed Tulipa Darwinii with Tulipa Fosteriana, a wild tulip discovered in central Asia and named after Sir Michael Foster, who collected these bulbs in 1904 in the mountains near Samarkand and introduced them to Europe. This hybrid, which is noted for the size of its brilliantly coloured flowers … they can measure as much as 15cm in diameter (say, 6 inches in old money) when fully opened … was, and is, called the ‘Darwin hybrid.’ Most of the tulips we grow in gardens and parks today are variants of the Darwin hybrid.

But Charles Darwin has another, lesser-known connection with the tulip. His restless brain had observed that plants seemed to make circular movements as they grow. In a much less well-known book than his famous ‘The Origin of the Species,’ Darwin wrote about what he termed ‘tulip circumnutation’ – the fact that a growing tulip stem turns right round during every period of four hours or so. This book, ‘The Power of Movement in Plants’, was first published in 1880, two short years before his death at the age of 73. Darwin hypothesised that this movement was built in to the plant’s very being … in other words, it was the plant’s natural behaviour. Unsurprisingly, this theory was also challenged since, while we expect plants to grow taller and wider as they develop, we don’t really expect to be told that they possess the power of movement. The power of gravity, it was argued, was what actually caused this movement. But in the first decade of this, the 21st century, experiments on board the International Space Station established that Darwin was right; for tulip bulbs grown in the weightless environment of an orbiting satellite circumnutate, albeit that this phenomenon is greatly amplified by gravity. However, given that watching plants circumnutate is, to the humble gardener like myself, rather similar to the thrill of watching paint dry, I shall leave my Darwin hybrids to get on with what they do naturally without watching too closely!