Ten of Leiden's twenty remarkable trees stand inside one garden. Hortus Botanicus, founded in 1590, keeps a tulip tree sown by professor Herman Boerhaave in 1716, the first zelkovas ever to leave Japan and the thickest horse chestnut in the Netherlands. Beyond the garden walls: a beech named for a student writer on the medieval fortress mound, two planes and a willow around a statue in the Van der Werfpark, a Caucasian wingnut that beat a copper beech in a public vote, and a Persian ironwood grove that gave its name to a garden cultivar now sold across Europe.
0 of 20 visited in Leiden
1
The Tulip Tree of Boerhaave
Tulip Tree (Liriodendron tulipifera) · about 310 years · Academiewijk
This tree exists because a London apothecary put a Virginia seed in the post. On 1 October 1716, botanist Isaac Rand shipped seed of an American species barely known in Europe to Leiden; eleven days later, on 12 October 1716, the Hortus Botanicus's own professor Herman Boerhaave sowed it in the garden that still bears the tree today. Boerhaave was not primarily a botanist. He is remembered as one of the founders of modern clinical medicine, teaching physicians from across Europe to examine patients at the bedside rather than argue from old texts, and the same instinct for direct observation over inherited authority shows up in his own tidy planting record for this tree, the reason its age is unusually certain for something three centuries old. The Hortus calls it the oldest tulip tree on the European continent, the species having only reached English cultivation in 1663 and taken decades more to spread further. Its yellow-green, cup-shaped flowers only appear once a tree reaches real maturity, easy to miss on a young specimen and unmistakable on one this size. It stands near the garden's entrance, a short walk from the Rapenburg canal, three centuries into a life that started as cargo.
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Photo: Txllxt TxllxT (CC BY-SA 4.0)
2
The Ginkgo of the Hortus
Ginkgo (Ginkgo biloba) · about 240 years · Academiewijk
Planted in 1785, this ginkgo spent a century and a half as what botanists call, without much romance, a male specimen, producing only the small catkins that never make seed. In 1935, gardeners grafted several female twigs onto its branches, cut from a ginkgo at Huis ten Donck, a country estate near Rotterdam. Only one graft took. It still lives today, a single genetically female branch grown into an otherwise male tree, and every autumn that one branch alone produces the species' distinctive plum-like seeds, whose fleshy coating gives off a smell closer to rancid butter than to fruit, an insect lure rather than a flaw. Ginkgo biloba is the sole surviving member of an entire plant order, its lineage traceable in the fossil record to roughly 270 million years ago, long before flowering plants existed at all, which makes this specific tree's mid-1930s surgery a strange collision of eras: a living fossil, tinkered with using the grafting techniques of a 20th-century orchard. The Hortus built its greenhouse complex around the tree in 1938, close enough that the ginkgo effectively anchors the entire glasshouse wing rather than sitting apart from it.
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Photo: Rudolphous (CC BY-SA 4.0)
3
The Weeping Beech of the Hortus
Weeping Beech (Fagus sylvatica 'Pendula') · about 185 years · Academiewijk
An Englishman gave this tree its first paper trail. George Loddiges, a London nurseryman whose own family ran one of Europe's great commercial gardens, documented it in 1836, and the Hortus dates the tree itself to around 1840, making it a weeping beech, a cultivar with heavy main branches held almost horizontal and side branches that trail down to the ground, grafted onto ordinary beech rootstock since the weeping form does not come true from seed. It grows directly beside the garden's pond next to an equally old fernleaf beech, the two forming one of the Hortus's most photographed corners, dense green tents a visitor can walk directly beneath rather than merely past. Age has not been kind to the original tree lately; its condition has been declining for some years, enough that the Hortus planted a younger weeping beech beside it in 1982, a gift after the sapling appeared at Amsterdam's Floriade garden show that year, deliberately positioned as an eventual successor rather than a separate attraction. Nothing here pretends the older tree will stand forever. It has already outlived the nurseryman who first wrote it down by more than a century, and for now it is still the one worth walking to.
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Photo: Xsandriel (CC BY-SA 4.0)
4
The Golden Chain of the Hortus
Golden Chain Tree (Laburnum anagyroides) · about 300 years · Academiewijk
For decades this tree was sold on a story its own garden no longer believes. A popular account claimed it dated to 1601, planted during the tenure of the great botanist Carolus Clusius, and the myth gained a kind of proof in 1931 when a caretaker named Veendorp found several fused trunks with a great many growth rings inside and read that as confirmation. The Hortus's own garden records undercut the claim twice: their archival research found the fused-trunk trick had inflated the ring count, and their own 1601 planting inventory does list a laburnum by the entrance that year, but places it somewhere other than where this one now stands. The documented evidence instead points to the 1720s, sown by Herman Boerhaave, the same professor responsible for the garden's tulip tree a few years earlier. Roughly 300 years old rather than 400, it remains modest in size for its age, a small, unshowy tree next to the tulip tree and ginkgo it shares the garden with, patched up with restorative surgery since at least 1972 and still putting out its bright yellow, pea-family flower clusters every late spring. What makes the story worth telling is not the tree's stature but the correction itself: an institution with every incentive to keep the more romantic number instead published the less impressive, better-supported one.
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5
The Beets Beech of the Burcht
Copper Beech (Fagus sylvatica f. purpurea) · about 185 years · Binnenstad
This tree is named after a student who wrote one of the Netherlands' best-loved books while it was still young. Nicolaas Beets studied theology in Leiden through the 1830s and, in 1839, the same year this copper beech was planted on the slope of the city's medieval fortress mound, published Camera Obscura under the pseudonym Hildebrand, a collection still assigned in Dutch schools today. Beets spent much of his student life around the Burcht, an 11th-century shell keep the municipality bought in 1651 and turned into a public park, and in 1989 the city formally named the tree in his honour, unveiling a bench beside it the same day. At 4.72 metres in circumference it is the thickest tree on the mound, one of a handful of veterans that survived the winter of 1945, when nearly every other tree in Leiden was felled for fuel during the Hunger Winter but the Burcht's older specimens were deliberately spared. That survival is now in question again, from a different direction: a root-rot fungus has been quietly turning the tree's root system to pulp, and as of the most recent inspection the municipality was investigating whether anything could extend its life rather than simply waiting for it to fall.
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Photo: Marianne Cornelissen-Kuyt (CC BY-SA 4.0)
6
The Groenesteeg Beech
Copper Beech (Fagus sylvatica f. purpurea) · about 200 years, likely planted around the cemetery's 1813 founding · Groenoord
Two beech varieties grafted together, growing at different rates for two centuries, is why this one looks nothing like a normal beech. A copper beech was grafted low onto a common green beech rootstock, standard practice since copper beech does not breed true from seed, but the mismatched growth rates produced an unusually broad, gnarled base, branches starting barely two metres up, topping out into a comparatively slender 15-metre crown that still spreads 24 metres wide. Groenesteeg cemetery was laid out in 1813 over one of Leiden's demolished city fortifications, and the tree was likely planted around that founding date, making it roughly 200 years old, a genuine rarity since few beeches live that long anywhere. Measured at 6.5 metres in circumference, it is officially the thickest beech in the Netherlands and the thickest tree in the entire province of South Holland, wide enough that calling it merely large undersells the effect of walking up to the trunk itself. In October 2025 it placed fourth in the national Boom van het Jaar (Tree of the Year) public vote, drawing over a thousand votes on its own oddity and scale alone, beaten only by a giant sequoia in Enschede and two other regional finalists. Like its neighbour on the Burcht mound, it is fighting a root fungus, though here the cemetery's caretakers are actively treating it, with annual nutrient injections and a policy of leaving fallen leaves in place to feed the soil around its base.
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Photo: Rudolphous (CC BY-SA 4.0)
7
The Date-plum of the Hortus
Date-plum (Diospyros lotus) · planted 1700-1750, so between 275 and 325 years · Academiewijk
Children call this one the Halloween tree, and the holes in its trunk have a stranger history than the nickname suggests. Late in the 19th century a maple seeded itself inside the trunk of the date-plum and grew there. Nobody took it out for roughly forty years, until 1931, and the cavities it left behind were then packed with concrete. Another forty years passed before the tree surgeons at Copijn removed that concrete again, which is how the openings you can see today came to exist. Iron pins were fitted inside what was left of the trunk to hold it together, and they are still doing that work. The national monumental tree register dates the tree to 1740, which would make it the second oldest in the Hortus Botanicus after the tulip tree Herman Boerhaave sowed in 1716. Its recorded planting band is wider, 1700 to 1750, so read the age as somewhere between 275 and 325 years in the same bed. Date-plums are either male or female, and this is a male, so it never fruits. The blue-black fruit the species is named for hangs on a younger female specimen the garden keeps in the fern garden instead. This tree offers a hollow trunk held up by ironmongery and a nickname it earned honestly.
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8
The Old Plane of the Plantsoen
London Plane (Platanus x acerifolia) · planted 1800-1850, so between 175 and 225 years · Plantsoen
This plane tree was already standing before the park around it existed. The Plantsoen was laid out between 1835 and 1842 as a job-creation scheme, an English landscape park built over Leiden's demolished bolwerken, the earthworks that had defended the city until they stopped being useful. Salomon van der Paauw designed it, which is why there are no straight paths, why the sightlines keep opening onto the water of the Singel, and why there has been an aviary here since 1867. The register dates this plane to the 1820s and calls it the oldest tree in the park, older than the layout it stands in. Its formal planting band is wider, 1800 to 1850, so its age is somewhere between 175 and 225 years. Planes became the workhorse of European city parks because they put up with compacted soil, air that would finish off a beech, and hard pruning, which is why so many survive from exactly this period of municipal park building. Most of them went into new ground as young stock. This one, by the register's dating, was already a tree when the diggers arrived. Stand at Plantsoen number 1 and look up the trunk: the flaking bark gives the species away, and above it sits a crown that has had two centuries to fill out.
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9
The Horse Chestnut of the Witte Singel
Horse Chestnut (Aesculus hippocastanum) · planted 1800-1850, so between 175 and 225 years · Academiewijk
At 5.8 metres round, this is the thickest horse chestnut in the Netherlands by the national monumental tree register's own measurement. It stands at the edge of the Hortus Botanicus with its roots almost in the water of the Witte Singel, and the register's note dates it to 1841, inside a recorded planting band of 1800 to 1850. There is a hollow in the trunk on the water side, fitted with iron pins to stop the remaining wood pulling itself apart, which is the standard treatment for a veteran that has outgrown its own structural margin. It has a problem every horse chestnut in northern Europe now shares. The horse chestnut leaf miner, a moth whose larvae eat the tissue between the two surfaces of a leaf, reached the Netherlands in the late 1990s and browns the foliage from midsummer onward. It disfigures without usually killing, so a chestnut in August looks considerably worse than it is. Come in May instead, when the flower candles are up and none of that has started. Horse chestnuts went into Dutch cities by the thousand in exactly this period, mostly along avenues and canal banks, and almost none of them reached this girth. Conkers drop here in September, onto a bank where the water does half the collecting for you.
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10
The Siebold Zelkova
Saw-leaf Zelkova (Zelkova serrata) · the register's band says 1800-1850 while its own note says 1858, so between 165 and 225 years · Academiewijk
These are the first zelkovas that ever left Japan. Philipp Franz von Siebold, the physician who spent the 1820s on the Dutch trading post at Deshima and sent home more Japanese plants than any European before him, brought zelkovas out with him in 1830. Two of them ended up here. One grew as a single trunk and stands at the centre of the Japanese garden; this one came up with five stems, so the register measures its girth on the thickest of them, about two metres, which undersells the mass of the thing considerably. The dating needs stating plainly, because the register disagrees with itself. Its planting band puts the tree between 1800 and 1850, while its own note says the two Leiden zelkovas went into the ground in 1858 and 1860. Take the age as somewhere between 165 and 225 years, and if you know which is right, tell us. Zelkova serrata is a relative of the elm that turned out to be largely resistant to Dutch elm disease, which is a good part of why it appeared on European planting lists after the 1970s, when the elms were dying in every city on the continent. This tree predates that fashion by more than a century, and it got here because one man wanted Japan in a Dutch garden.
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Photo: Rudolphous (CC BY-SA 4.0)
11
The Leaning Catalpa of the Hortus
Catalpa (Catalpa sp.) · planted 1820-1830, so between 196 and 206 years · Academiewijk
This catalpa is kept out of the canal by cables tied to another tree on this list. It stands right on the edge of the singel behind the glasshouse, and at some point it leaned far enough that it was going to end up in the water. The answer was anchors, run across to the zelkova in the Japanese garden, and that arrangement is what still holds it upright. Two monumental trees, one carrying the other. The register dates it to 1820, inside a recorded band of 1820 to 1830, and counts it among the five thickest catalpas in the Netherlands. The catalpas planted across Europe came mostly from the American south and arrived in the 18th century for exactly the reason people still plant them: outsized heart-shaped leaves that come late and drop early, upright trusses of white flowers marked purple and yellow in the throat, then long thin seed pods that hang on all winter like forgotten string. It is a soft-wooded, brittle tree, never built for two centuries of Dutch wind on an exposed bank, which makes the cabling less an indignity than the reason there is still anything here to look at. Walk behind the glasshouse and follow the line of the water until you find the one that is not standing straight.
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12
The Plane at Plantsoen 11
London Plane (Platanus x acerifolia) · planted 1850-1860, so between 166 and 176 years · Plantsoen
The London plane is a hybrid nobody set out to make. Somewhere in the 17th century an oriental plane from the eastern Mediterranean crossed with an American one, probably in a nursery, and the accident grew faster than either parent, shrugged off coal smoke and put up with having its roots under paving. Europe then planted it in every city it had. This one went into the Plantsoen in the 1850s, on the stretch of the park at number 11, more than a decade after the park itself was finished in 1842. The Plantsoen was Leiden's first proper public park, cut into the line of the old defensive bolwerken between 1835 and 1842 as work for the unemployed, to a design by Salomon van der Paauw, and it is now part of the Singelpark, the green ring the city has been stitching back together around its historic centre. The register notes that no other part of that ring carries as many different old trees. Bark is the thing to look at here. Planes shed theirs in irregular plates, one reason they cope with dirty city air, and it leaves an old trunk looking like military camouflage in cream, olive and grey. This one has had roughly 170 years of shedding, and it stands on the water, which is the view the whole park was drawn around.
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13
The Plane by the Garenmarkt Entrance
London Plane (Platanus x acerifolia) · roughly 140 years, planted in the 1880s · Binnenstad
A ship loaded with gunpowder exploded here in 1807 and flattened much of this part of Leiden. The rubble field it left was known as the Grote Ruine, and it stayed waste ground until 1886, when municipal architect Daniel Knuttel laid a park across the scar. This plane, a few steps inside the Garenmarkt entrance, has stood over the result since close to the beginning.
The national register of monumental trees puts its planting in the 1880s, which makes it around 140 years old. A historical survey of the park reaches the same answer from the other direction: the two monumental planes here measure 1.64 and 1.60 metres across the trunk, and trees that thick can very well date from the laying out of the park. Which of those two figures belongs to this tree and which to its neighbour on the southeast side, nobody has recorded, so we have not assigned one. If you have measured it, tell us.
At the centre of the park stands Pieter van der Werff, the mayor who refused to surrender Leiden to the Spanish through the siege of 1573 and 1574. The park is small, free and open at any hour, with entrances on the Garenmarkt and the Doezastraat, and the two planes, the willow at the water and the silver maples make a circuit you can walk in ten minutes.
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14
The Plane on the Southeast Side
London Plane (Platanus x acerifolia) · roughly 140 years, planted in the 1880s · Binnenstad
Leiden's monumental tree register counts this plane and the one at the Garenmarkt gate as two separate entries. The park's own historical survey counts them as a pair, and gives their trunk diameters as 1.64 and 1.60 metres without saying which belongs to which. Sixty-five metres of grass separate them.
This is the one on the southeast side, the corner nearest the Doezastraat, and the register dates its planting to the 1880s. The survey's argument for the same date is the trunk itself: planes of that thickness can very well go back to 1886, when municipal architect Daniel Knuttel laid the park out.
What he laid it out on is the more interesting half. In 1807 a ship carrying gunpowder exploded in the middle of the city and flattened much of this quarter. The ruined ground stayed empty for close to eighty years, known simply as the Grote Ruine, until the park covered it. The statue at its centre is Pieter van der Werff, the mayor who held Leiden through the Spanish siege of 1573 and 1574, which means the park commemorates one siege while standing on the wreckage of a different disaster entirely.
Free, open at any hour, fifteen minutes on foot from the station. No girth has been published for this tree on its own. If you measure it, we will record it.
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15
The Weeping Willow of the Van der Werf Statue
Weeping Willow (Salix babylonica) · roughly 120 years, planted in the 1900s · Binnenstad
The register entry for this willow has a field for its history. The field says: unknown.
That is close to the whole record. The Dutch national register of monumental trees lists it as standing at the water, by the statue, in the Van der Werfpark, and puts its planting between 1900 and 1910, which makes it roughly 120 years old. It is municipal property and anyone can walk up to it. Beyond that one entry we have found nothing: no newspaper piece, no park survey, no local history page that names this tree at all. The park's two planes and its silver maples get written about. The willow does not.
Even the species is a common name rather than a determination. The register calls it a Treurwilg, weeping willow, and gives no scientific name. In Dutch parks that usually means Salix babylonica, though the hybrid Salix x sepulcralis 'Chrysocoma' is the commoner modern planting, and nothing we found settles which of the two is standing here.
What it does have is position. It stands at the water's edge beside Pieter van der Werff, the mayor who held Leiden through the Spanish siege of 1573 and 1574, in a park laid out in 1886 over ground a gunpowder explosion had left in ruins. If you know who planted it, or what it is, tell us.
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16
The X-factor Wingnut of the Plantsoen
Caucasian Wingnut (Pterocarya fraxinifolia) · roughly 140 years, planted in the 1880s · Plantsoen
In 2009 Leiden held a public vote to decide which of its trees had the X-factor. This one won with 160 votes. The runner-up, a copper beech, got 83.
The contest was run by the Bomenstichting together with the VSB-fonds, De Groene Stad and the Koninklijk Nederlandsche Heidemaatschappij, and alderman John Steegh turned up to honour the winner formally. The margin is the part worth noticing: nearly two to one against a copper beech, which is the kind of tree that normally wins these things.
A Caucasian wingnut earns it. It is a relative of the walnut from the forests between the Black Sea and the Caspian, large and fast growing, with pinnate leaves long enough to look tropical and chains of winged nutlets that hang off the branches through late summer like green rope. Nothing else in the Plantsoen looks remotely like it.
The register dates its planting to the 1880s, roughly 140 years ago, which puts it a few decades younger than the park. The Plantsoen was laid out between 1835 and 1842 on Leiden's old city bulwarks, an English landscape park designed by Salomon van der Paauw and built in part to give unemployed men work. No girth has been published for this tree. If you take a tape to it, we will add the number.
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17
The Persian Ironwoods that Named Themselves
Persian Ironwood (Parrotia persica) · roughly 110 years, planted 1910-1920 · Plantsoen
Nurseries across Europe sell a Persian ironwood called Parrotia persica 'Het Plantsoen'. It is named after this park, and these are the trees it is named after.
The naming was done by Esveld, the Dutch nursery that introduced it, and its catalogue explains the odd name without ceremony: the plant owes it to Het Plantsoen in Leiden, a park on the canal, where this weeping form of the ironwood, planted at the beginning of the twentieth century, was named by them. The national register agrees on the timing, putting the planting between 1910 and 1920, and gives the reason for protection as dendrological. It counts three ironwoods here, standing together near number 45, which is why they appear as one entry rather than three. Their shape is the broad, low, spreading form the cultivar was named for.
A Persian ironwood is a witch hazel relative and behaves like one. Small dark red flowers open in February and March on bare branches, before anything else in the park has moved. In October and November the leaves turn yellow, then orange, then red and purple, often several of those at once on one tree.
The park itself was laid out between 1835 and 1842 on Leiden's old bulwarks, in the English landscape style, to a design by Salomon van der Paauw. No girth has been published for any of the three.
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18
The Elm Inside the Burcht
Dutch Elm (Ulmus x hollandica) · roughly 120 years, planted in the 1900s · Binnenstad
Most of the street elms in the Netherlands are gone, killed since the 1970s by the disease that carries the country's name. This one is still standing, on top of an artificial mound raised in the eleventh century in the middle of Leiden, inside the ring wall of the Burcht.
The national register dates its planting to the first decade of the twentieth century and admits in the same breath what that is worth: the period is an estimate, and no historical records are known. Roughly 120 years old, then, with the register's own uncertainty attached. A Dutch heritage survey of the castle confirms what grows up there without dating any of it, describing several monumental trees inside the walls, two beeches and one elm, which give the interior its particular character. This is the elm.
Trees of this kind are now maintenance rather than luck. The survivors tend to be kept alive on purpose, with fungicide injected year after year, because an elm this size cannot be replaced by planting another one.
The mound is older than all of it. Leiden bought the Burcht in 1651 and turned it into a public park, which it still is: free, open at any hour, and reached by a flight of steps up the side of the mound. The beeches the survey mentions are up there with it.
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19
The Fern-leaved Beech of the Nut Field
Fern-leaved Beech (Fagus sylvatica f. asplenifolia) · planted 1800-1850, and 1818 by the register's own note, so between 175 and 225 years · Academiewijk
The oldest fern-leaved beech in the Netherlands is also one of the three thickest, and it has had two centuries of elbow room to get that way. The register puts it in the ground in 1818, while the Hortus was growing and being relaid in the English landscape style, out on the open patch the garden calls the Notenveld, the nut field, among trees kept here for what they drop. Nothing crowds it, so it grew the way a beech grows when nothing is competing for the light: outward rather than upward, into one enormous low dome. Fern-leaved beech is a form of the ordinary European beech whose leaves are cut into narrow lobes, fine enough that from a few metres away the crown reads as feathered rather than leafed. Up close the trunk does something else entirely. It is vaulted and swollen, bulging in some places and open in others, the sort of surface people put a hand on without quite deciding to. Come in spring and the ground competes for attention: stinzenplanten, the old Dutch estate bulbs that naturalise under mature trees, come up in sheets underneath before the beech leafs out and takes the light back. The formal planting band on the register runs 1800 to 1850, so the age is between 175 and 225 years.
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20
The Grafted Ash of the Hortus
Narrow-Leaved Ash (Fraxinus angustifolia) · planted 1810-1820, so between 206 and 216 years · Academiewijk
This ash has spent two hundred years slowly swallowing its own graft. It was planted in 1818 and grafted, probably at around two metres up the stem, where the join left the swelling that grafts always leave. The Dutch word for that bulge is slobbertrui, a baggy jumper, and on this tree it has travelled downward. The register records the swelling sinking further down the trunk decade by decade, until today it sits a few decimetres above the soil on one side and less than a decimetre on the other. Partly because of all that accumulated tissue, the register calls it the thickest narrow-leaved ash in the country. Fraxinus angustifolia comes from southern Europe and North Africa, drier and warmer country than a botanical garden in the Dutch coastal plain, and it wears the family look in a slimmer cut: leaflets narrower and more sharply pointed than the common ash standing beside every ditch in the province. Its recorded planting band runs 1810 to 1820, which puts it a little past two hundred years old. The garden's fern-leaved beech went into the ground the same year. Ash dieback has been working through Europe's ash population for two decades now, killing young and old alike, which makes a healthy veteran of this size worth the detour on its own.
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