Curious Questions: What caused Tulipmania?

The extraordinary inflation in tulip prices in the early 17th century has gone down in history as one of humanity’s most extraordinary speculative bubbles. But was it really that simple? Anna Pavord explains what happened — and why.

Tulipmania began in the Netherlands in 1634, ended in 1637 and has puzzled historians ever since. How could one single tulip bulb have ever been sold for the equivalent of 15 years’ wages for an Amsterdam bricklayer?

The Dutch East India Company had recently been launched and this marked a period of great prosperity for the Dutch. The money to speculate was available and the tulip had an unique trick: it could change colour, seemingly at will.

The tulips that drove the mania were not ordinary ones, but flowers that, even if planted as plain purple, yellow or red, sprang up with the base colour splintered and broken — ‘feathered’ or ‘flamed’ were the terms used — in a contrasting shade.

The coveted bulbs couldn’t be produced to order, because nobody then knew how the transformation came about. That produced all the classic ingredients needed for a boom: money to spend and speculate with, plus a fashionable commodity in short supply thanks to the vagaries of nature.

What was it that made tulips break? At the time of Tulipmania, nobody knew. Some growers spread coloured paints on their tulip beds, thinking the colour would drift through the earth and soak into the bulb, but that wasn’t the answer.

The truth emerged only 300 years later, unravelled in 1927 by Dorothy Cayley, a mycologist working at the John Innes Horticultural Institute. She discovered that the ‘breaks’ that produced the tulips so prized during tulipmania were caused by a virus spread by aphids.

A Flemish painting depicting a tulip bulb transaction.

Why did the answer not come sooner? The word ‘virus’ wasn’t understood in the modern sense until the 1880s and the electron microscope, which enabled researchers to track the virus, did not appear until the 1920s.

Miss Cayley discovered that the effect of the virus was to partly suppress the laid-on colour of a tulip, its anthocyanin, leaving the underlying colour, always white or yellow, to show through.

The tulip is the only example of a flower made more beautiful by a disease, but the mother bulb is weakened. As a result, it produces few offsets, hence the shortage of the essential commodity traded during the time of tulipmania.

Incidentally, many of the most extreme stories that surround Tulipmania — distraught traders throwing themselves into canals and so on — have been debunked in recent years by historian Anne Goldgar, but there is no doubt that fortunes were indeed won and lost, even if many of them were mostly on paper, and the losers were generally people already wealthy enough to take the hit.