Cannabis – the source of the drug marijuana – grew wild across Europe at the end of the Stone Age, but by the time early farmers reached the continent it was vanishing. It seems Europe’s first farmers just missed out on the opportunity to cultivate cannabis and reap its benefits – including its mind-bending properties.
Researchers often use ancient pollen from archaeological deposits to work out which plants once grew in a place. However, it’s difficult to do this for cannabis, because its pollen looks just like that of a related plant, the common hop.
Now at the University of Vermont in Burlington and his colleagues think they have a solution to the cannabis/hop identity problem. He argues that wild versions of the two plants grow in different environments: cannabis on cold grassy steppes, hop in warmer woodlands. If the other pollen trapped in an ancient deposit comes from steppe-like plants, McPartland says, we can assume any cannabis-like pollen really does come from wild cannabis.
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The team re-examined pollen data from almost 500 European archaeological sites, dating back between 18,500 and 1200 years. They concluded that wild cannabis grew across Europe deep in prehistory. But the continent warmed up between 10,000 and 7500 years ago, so steppe-like conditions gave way to forests – and cannabis gave way to the hop. “That’s global warming for you,” says McPartland.
Marijuana farming
between 9000 and 7500 years ago, just as cannabis was vanishing. The pollen record suggests they didn’t farm it, says McPartland. “If it wasn’t there they couldn’t domesticate it.”
The researchers argue cannabis wasn’t cultivated in Europe until the Bronze Age, about 4500 years after farmers reached Europe. At this point, cannabis-like pollen is routinely found with that of other crops.
The team suspects cannabis returned to Europe because pastoralists from the Eurasian steppe carried it there. Genetic evidence suggests these pastoralists swept into Europe during the Bronze Age.
In 2016, at the Free University of Berlin, Germany, co-authored another study that implicated the steppe pastoralists in the spread of cultivated cannabis. He says McPartland’s study is innovative, but is not yet convinced that cannabis disappeared from Europe as farmers arrived.
Useful dope
Even after their 4500-year wait for cannabis, it’s not clear European farmers could then harness its mind-bending properties, says cannabis researcher Robert Clarke, cofounder of in Los Angeles. He points out that the varieties of cannabis growing in Europe today don’t contain much of the psychoactive chemical tetrahydrocannabinol. “Although it still could have been used medicinally.”
Instead, Clarke thinks cultivated cannabis became important in Europe because the plant has other uses. In particular, its fibres can be made into textiles.
However, McPartland thinks it’s possible the European farmers did use cannabis as a drug. The is from 8000 years ago in Georgia, and the practice may not have spread widely through Europe until much later. “Even muted psychoactivity would have been appreciated by people who did not yet have alcohol,” says McPartland.
Vegetation History and Archaeobotany
