It's early October, and Seoul has started walking with its head down. Not because of bad news. Because of ginkgo seeds.
They've been dropping on the sidewalks since mid-September, squishy little yellow balls that look harmless and very much aren't. This morning, too, I walked to work watching my feet, step by careful step.
So here's my one piece of advice before anything else. Watch out for the yellow fruit under your feet, or the smell will follow you all the way into your room. I mean it.
Quick facts
- Seoul’s official tree since April 3, 1971
- 2026 peak color expected around October 30 (Korea Forest Service)
- Samcheong-ro: about 1.2 km of ginkgo-lined road
- Hongcheon Ginkgo Forest: October only, 10 a.m. to 5 p.m., free
- Shaking street trees for nuts can mean a fine of up to 100,000 won
So what is that smell?
The yellow "fruit" isn't really a fruit. It's the fleshy outer coat of the seed (botanists call it the sarcotesta), and when your shoe squashes it, out comes butyric acid. Same stuff you get in rancid butter and, well, vomit. Throw in a bit of hexanoic acid and you've got the classic Seoul-in-October aroma, which Koreans usually compare to something I won't type here. You can guess.
Ginkgo leaves piling up along a brick wall in Nowon, northern Seoul. The leaves are the easy part. Photo: A Korean's Take
Don't pick them up with bare hands, either. The coat has ginkgolic acid and bilobol in it, and those can give some people a nasty rash. Curious tourists, I'm looking at you.
And the shoe problem is very real here. We take our shoes off at the door, so the smell just parks itself in the entryway. You come home, kick off your sneakers, and an hour later you're wondering who left old cheese somewhere.
Why does Seoul have so many?
Because the ginkgo is Seoul's official tree, and has been since April 3, 1971. The city had its reasons. It's pretty, it lives practically forever, it shrugs off air pollution and bugs, and in autumn it turns a yellow that looks almost fake. By 2004 ginkgos made up 42.2 percent of Seoul's roughly 275,000 street trees.
There's a catch, obviously. Only female trees make the smelly seeds, and you can't tell a ginkgo's sex until it's about 15 years old and starts flowering. So for decades, cities planted them blind and hoped. As of 2024 Seoul had 102,794 ginkgo street trees, and 25,127 of those were female. Roughly one in four.
Before the ginkgo, the favorite street tree was the weeping willow (36 percent of Seoul's street trees back in 1975). Every spring they let loose clouds of white fluff. In the past, those willow street trees caused a lot of allergy problems every spring, and from the late '70s the city started cutting them down. By 2014 there were 31 left. So Seoul traded a spring problem for an autumn one. Some would call that progress. I'd call it a sideways move with better colors.
How the city fights back
Seoul doesn't just sit and wait for the stink. From early September, district crews go out with vibration harvesters (basically big shaking machines on aerial work trucks or excavator arms) and rattle the seeds down into nets before they hit the pavement. Pretty heavy machinery for something the size of a grape. The nuts they collect get safety tested and then donated to senior centers and welfare facilities, which is a nicer ending than getting stepped on.
The long-term fix is changing the trees. Back in 2011 the National Institute of Forest Science came up with a DNA test that tells a young ginkgo's sex from a single leaf, so new plantings can be all male. Old female trees get swapped out one district at a time. Gangbuk-gu replaced 1,053 of them in 2020 and 2021, and smell complaints went from 93 to zero, at least for a while. This year at least 792 ginkgos across Seoul's districts are on replacement lists, according to a count by the Korean Federation for Environmental Movement, and the group isn't happy about it. Their argument is that a big old tree is worth more than a few weeks of bad smell. Hard to disagree, honestly, unless you just stepped on one.
They are working on changing the tree species, but it isn't easy. A street tree takes decades to grow, and nobody wants a boulevard of skinny saplings.
Oh, and don't go shaking street trees for free nuts. The trees belong to the district, so taking the seeds can count as theft, and the Minor Offenses Act allows a fine of up to 100,000 won. That's a pricey snack.
Where the yellow is worth it
Now the good part. The Korea Forest Service expects ginkgo to peak around October 30 this year, so the next few weeks are when the streets go gold.
In central Seoul, the easy pick is Samcheong-ro, the road that runs along Gyeongbokgung's stone wall up toward Samcheong-dong. The city lists about 1.2 km of ginkgo there as one of its autumn streets, and with the palace wall on one side and little galleries on the other, it's hard to take a bad photo. The Deoksugung stone-wall road works too if you're already downtown. Small tip: on any street, the trees with a clean sidewalk under them are the males. The others, you'll figure out fast.
Ginkgo trees towering over a tiled roof at Gyeongbokgung Palace, Seoul. Photo: Iann kim / Unsplash
If you've got a free day, two places outside the city are worth the trip. Hongcheon Ginkgo Forest in Gangwon Province is about 2,000 ginkgo trees planted in tidy rows five meters apart. A man started planting them in 1985, hoping the mineral spring nearby would help his wife's health. It's a private forest and it only opens to the public in October, 10 a.m. to 5 p.m., free. So it's this month or next year.
Then there's the giant. The ginkgo at Yongmunsa Temple in Yangpyeong is estimated at more than 1,100 years old and 42 meters tall, the oldest and tallest in Korea, and it's been a natural monument since 1962. Legend says the monk Uisang stuck his walking stick in the ground and it grew into this. I can't vouch for the legend. But the tree still drops about 350 kg of nuts a year, so maybe watch your step there too.
And yes, people eat them
This is the part foreigners never believe. Inside the stinky thing there's a nut, and Koreans love it. Eunhaeng, ginkgo nuts, get pan-roasted with a little oil and salt until they turn this lovely jade green, and then they're a snack with beer or soju. You'll also see them on skewers, tucked into samgyetang (that whole-chicken soup), or cooked into rice.
Two rules, though. Always eat them cooked. And don't go overboard, because they're mildly toxic in large amounts. Korea's Ministry of Food and Drug Safety says no more than about 10 a day for adults and 2 or 3 for kids. Ten sounds like plenty until the plate is in front of you and the second bottle shows up.
So look up for the gold and look down for the seeds. And check your soles before you go inside.
Official info
Dates, prices and hours change, so check before you go (details as of 2026-10-07). These pages are in Korean.
- Korea Forest Service: 2026 autumn foliage peak forecast
- Hongcheon County: Ginkgo Forest (open in October)
- Korea Heritage Service: Ginkgo Tree of Yongmunsa Temple
More from this blog:
- Korean Hiking Culture: Why Koreans Dress Like They're Climbing Everest (with a note on when autumn foliage really peaks)
- Seoul Royal Palaces: Gyeongbokgung vs Changdeokgung vs Deoksugung
Would you put up with the smell for a street like that?
Top photo: ginkgo and maple leaves over a stone wall at Hyeonchungsa in Asan. Photo: olivia kim / Unsplash
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