Asparagus is native to the eastern Mediterranean region, though it also grows wild across northern Europe, northwest Africa, and as far east as Mongolia. The spears you buy at the grocery store most likely traveled from Mexico or Peru, the two countries that supply the vast majority of asparagus consumed in the United States.
The Plant’s Ancient Origins
Wild asparagus has grown across a surprisingly wide swath of the Old World for thousands of years. Its center of origin is the eastern Mediterranean, but the plant established itself naturally in central Europe, the Caucasus mountains, and western Asia. Ancient Egyptians and Greeks both prized it, and the Romans cultivated it systematically enough to leave behind detailed growing instructions that still hold up remarkably well.
Wild asparagus still grows today, often found along roadside fences and ditches near farm gardens, where birds perch and drop seeds they’ve eaten from the plant’s small red berries. In fall, the plant turns into a distinctive golden bush with thin, lacy, needle-like branches that’s easy to spot even from a car. Foragers use that fall sighting to mark locations, then return in spring to harvest the young spears before they branch out.
Where Your Grocery Store Asparagus Comes From
In 2022, the U.S. imported about 263 million kilograms of fresh asparagus, worth nearly $685 million. Mexico supplied the largest share at roughly 163 million kilograms, followed by Peru at about 97 million kilograms. Together, those two countries accounted for nearly 99% of all asparagus imports. Small amounts came from Canada, Ecuador, and France.
Mexico’s proximity to the U.S. gives it a logistics advantage. Asparagus is highly perishable, and Mexican farms can truck fresh spears across the border within a day or two of harvest. Peruvian asparagus, by contrast, typically travels by air or refrigerated ship, which adds cost. That’s reflected in the price difference: Mexico shipped a larger volume but at a lower per-kilogram cost than Peru.
Domestic production exists but has shrunk dramatically over the past few decades. States like Washington, Michigan, and California once grew large commercial crops. Rising labor costs and competition from imports pushed many U.S. growers out of the market. Oregon’s Umatilla County still harvests asparagus from roughly mid-April through the end of June, but operations like these represent a small fraction of what Americans eat.
How Asparagus Actually Grows
Asparagus is a perennial, meaning you plant it once and harvest from the same root system for 15 to 20 years or more. Underground, the plant develops a structure called a crown, a dense cluster of roots and buds that survives winter and sends up new shoots each spring. Those shoots are the spears you eat.
When soil temperatures warm in early spring, spears push through the ground and grow rapidly, sometimes several inches in a single day. Farmers harvest by cutting or snapping spears at ground level. New spears keep emerging for the duration of the harvest window, typically six to eight weeks. After that, growers let the remaining spears grow into tall, ferny stalks that photosynthesize and feed the crown for next year’s crop. A new asparagus planting requires patience: most growers wait two to three years before taking a full harvest, giving the crown time to build energy reserves.
White, Green, and Purple Varieties
All three colors can come from the same species. The difference is mostly about how they’re grown. Green asparagus is the standard: spears grow above ground, and sunlight triggers the production of chlorophyll that gives them their color. White asparagus grows entirely underground, shielded from light by mounding soil over the rows. Without sunlight, no green pigment develops, leaving the spears pale and giving them a milder, slightly more delicate flavor. White asparagus is especially popular in Germany and the Netherlands, where spring “white asparagus season” is a culinary event.
Purple asparagus is grown with just the tip poking above the soil surface. That limited sun exposure triggers anthocyanins, the same pigments found in blueberries and red cabbage, which tint the spear purple. Purple varieties tend to be slightly sweeter and more tender than green, with lower fiber content. The color fades to green when cooked at high heat, so some cooks serve it raw or lightly blanched to preserve the appearance.
Why It Makes Your Urine Smell
Asparagus contains a sulfur compound called asparagusic acid that your body breaks down during digestion. The main byproduct is methanethiol, a volatile sulfur molecule that gives post-asparagus urine its distinctive cabbage-like smell. This breakdown happens quickly, often within 15 to 30 minutes of eating.
Not everyone notices the smell, and for years scientists debated whether some people simply don’t produce it or whether some people can’t detect it. The answer appears to be both. Genetic variation affects the enzymes involved in breaking down asparagusic acid, so production varies. Separately, genetic differences in smell receptors mean some people lack the ability to detect sulfur compounds at low concentrations. You might be a producer who can’t smell it, a non-producer, or someone who both produces and detects it clearly.