Did life give us lemons? Or did we make them ourselves? The citrus family has an elaborate taxonomy, much of which precedes historical documentation.
So it’s difficult to say when, where, or how the first lemon trees appeared. Let’s look at the existing evidence and scientific speculation to determine if lemons are man-made.
A Hybrid Gone Sour
The lemons we know and love today evolved through natural and human-facilitated cross-breeding over many centuries.
In the 18th century, Swedish botanist Carolus Linneaus classified the lemon as a variety of citron. However, scientists now know that the lemon, or Citrus limon, is a hybrid of the citron and the bitter orange.
One of the original citrus fruits, the citron looks like a larger and more rugged lemon. It has a thick rind with ridged, bright yellow skin. Although fragrant, the citron produces little juice.
Also known as the sour orange, the bitter orange is a hybrid of two citrus plants: the pomelo and the mandarin. Unsurprisingly, bitter orange has a bitter taste. This sour fruit is the citrus usually used to make marmalade.
The combination of citron and sour orange also produced bergamot orange.
The lemon and rough lemon look similar. But the rough lemon is not the same as the lemon widely used today. The rough lemon results from a different pairing: the citron and the mandarin.
Geographic Origin & Natural Evolution
The exact origin of the original citrus fruits, much less the lemon, is unknown.
Archeologists rely on fossil records to date the origins of fruit. Unfortunately, limited fossil records exist for citrus fruits. But a fossilized citrus leaf discovered in southwestern China dates to eight million years ago.
Scientists have also traced the origins of citrus fruits. Using DNA evidence, they have placed the original citrus trees in the southern foothills of the Himalayas.
Without human intervention, the citrus plants stayed put. Until the climate shifted. Weaker monsoons and drier weather allowed the citrus plants to spread (and evolve) beyond the Himalayas over millions of years.
Human Cultivation Begins
Human-cultivated citrus has a somewhat shorter history – estimated at a mere 4,000+ years.
Traders, crusaders, and migraters spread the lemon across many continents over many centuries. It was a long, winding journey to where we are today.
Piecing together historical documentation (trade receipts, farming records, literature, etc.) provides a rough timeline:
- 3000 BC Earliest record of Citron
- 100 AD Lemons in the Middle East and North Africa
- 200 AD Lemons in southern Italy
- 700 AD Lemons cultivated in Egypt, Iraq, and Persia
- 760 AD Lemons in China
- 1000 AD Lemons introduced to Spain
- 1493 AD Christopher Columbus brings lemon seeds to the Americas
- 1494 AD Lemons cultivated in the Azores
- 1751 AD Lemons grown in California
- 1800s AD Lemons grown in Florida
(Note: these dates don’t necessarily reflect the beginnings of lemon cultivation in particular regions so much as the approximate first point of existing documentation.)
Until about the 10th century, people regarded the lemon tree as an ornamental tree rather than a food source.
In the 12th century, the palaces of Egypt and Syria prized lemons for their medicinal virtues.
As Spanish conquest spread lemons to the Americas, lemons gained popularity for flavoring and cooking.
Current Lemon Cultivations
Today, there are at least 200 distinct cultivars of lemons in the US alone (PDF).
These lemons are cultivated using selective breeding to prioritize desirable traits such as disease resistance, productivity, climate preference (humid vs. arid), and seed quantity. Cultivators might also breed lemons for specific uses, with some being better suited for lemon oil and others for juice.
Even after millions of years of evolution and thousands of years of human cultivation, lemons still have a narrow growing region. For instance, the trees won’t survive once temperatures dip below 20° Fahrenheit.
Given this cold intolerance, it’s not surprising that Arizona, California, and Florida lead lemon production in the US.
Nationwide, the US produces nearly two billion pounds of lemons and limes each year (USDA). But this number accounts for less than 5% of the world’s total lemon production.
Commercial planters primarily usually use grafting to propagate lemons trees. The rootstocks of lemons are disease-prone. So planters graft a stem from the desired lemon variety onto the rootstocks of other citrus trees (grapefruit, sweet orange, sour orange, tangelo, and mandarin orange). These rootstocks provide a more reliable foundation.
When grafted, the ‘Meyer’ lemon tree will fruit 2 to 3 years earlier than a budded tree. This tree will then produce fruit for at least 30 years.
Historians aren’t exactly sure when, where, or how the lemon originated. Making it challenging to answer the question, “are lemons man made?” But currently, no genetically modified lemons exist in the United States. So even if humans helped breed the lemons, they didn’t do so in a laboratory.