Stepping into a "Jurassic Garden": The Upper Botanic Garden of Dunedin
Updated: Sep 1
There is a moment in Dunedin’s Upper Botanic Garden when the city seems to disappear.
The traffic becomes distant, the air feels cooler and the path enters a world of enormous leaves, twisting branches and flowers growing high above your head. Rhododendrons that many visitors know as tidy garden shrubs have become trees. Giant lilies rise like floral towers from the woodland, while old pines form a canopy far overhead.
It feels less like walking through a city garden and more like entering a lush, prehistoric landscape.
At Fantail Tours, we sometimes describe it to our guests as Dunedin’s “Jurassic Garden.” It is one of our favourite places to show visitors because it is beautiful, peaceful and often completely unexpected.
New Zealand’s oldest botanic garden
Dunedin Botanic Garden was established in 1863, making it New Zealand’s first botanic garden.
Today, its approximately 30 hectares are divided into two distinct areas. The more formal Lower Garden contains lawns, flower beds, the Winter Garden glasshouse and many of the better-known ornamental displays.
The Upper Garden feels quite different.
Here, paths climb through mature trees and woodland collections. Birds move through the canopy, fallen leaves soften the ground, and plants are allowed to grow on a scale that can make visitors feel very small.
The Upper Garden is also home to the aviary, where native and exotic birds are cared for. South Island kākā bred here have contributed to wild populations at Orokonui Ecosanctuary, and the aviary supports the Dunedin Wildlife Hospital by providing a protected place for some recovering birds.
But the botanical stars of this part of the garden are undoubtedly the rhododendrons.
When a shrub becomes a tree
When we mention rhododendrons, many visitors imagine a rounded shrub growing beside a suburban driveway.
Then we take them into Dunedin’s Rhododendron Dell.
Here, the branches arch overhead, trunks are thick enough to resemble small woodland trees and entire pathways disappear beneath flowering canopies. Some specimens have been growing for more than a century.
The experience is a reminder that “rhododendron” describes an enormous and highly varied group of plants. Some are small alpine species that remain close to the ground. Others become genuine forest trees.
The name comes from the Greek words rhodon, meaning rose, and dendron, meaning tree—quite literally, a “rose tree.” In Dunedin’s Upper Garden, that name suddenly makes perfect sense.
Could Dunedin claim another world record?
Our visitors often tell us that they have never seen rhododendrons this large anywhere else.
Standing beneath plants more than eight metres tall and 11 metres across, it is easy to understand why. These are not the tidy garden shrubs most people recognise—they resemble mature woodland trees.
This made us wonder: where do the world’s largest rhododendrons grow? And, after Dunedin’s famous battle to retain the title of the world’s steepest street, could our city possibly claim another world record?
The answer depends on how “largest” is defined. Are we looking for the tallest wild rhododendron tree, the widest individual plant, the largest cultivated specimen or the biggest public collection?
The world’s tallest and largest recorded rhododendrons are found in the mountain forests of Asia. Guinness World Records lists a scarlet Rhododendron arboreum growing on Mount Japfü in Nagaland, northeastern India, as the largest recorded rhododendron, reaching approximately 20 metres.
Even larger measurements have been reported in southwestern China. In 1918, British plant collector George Forrest encountered an enormous rhododendron in Yunnan measuring approximately 25 metres tall, with a trunk 87 centimetres in diameter. Its size surprised European botanists, who were accustomed to thinking of rhododendrons mainly as shrubs.
Dunedin therefore cannot claim the record for the world’s tallest rhododendron. However, our century-old specimens may still rank among New Zealand’s largest and most impressive cultivated rhododendrons.
To establish an official record, the plants would need to be professionally measured and compared using a clearly defined category—something Dunedin understands rather well after the Baldwin Street story.
For now, we may not have another official world title. But when visitors stand beneath our enormous Rhododendron ‘Halopeanum’ and tell us they have never seen anything like it, the Rhododendron Dell certainly feels like a record-breaking place.
Where rhododendrons become giants
The greatest concentration of wild rhododendron species is found across the Himalayas and the mountain forests of southwestern China, northern India, Nepal, Bhutan and Myanmar.
This is where rhododendrons reach their most extraordinary natural scale.
In these cool, misty mountain forests, rhododendrons grow among other trees rather than appearing as small ornamental shrubs. Some species rise high into the forest canopy, with heavy trunks, enormous leaves and flowers appearing many metres above the ground.
Dunedin’s rhododendrons do not reach the same heights as the giants growing wild in Asia, but they demonstrate how large and architectural these plants can become when given suitable soil, moisture, shelter and enough time.
Why rhododendrons thrive in Dunedin
Dunedin’s cool temperate climate suits many rhododendrons exceptionally well.
They generally prefer cool conditions, acidic soil, reliable moisture and protection from extreme heat. The sheltered slopes of the Upper Botanic Garden provide many of these requirements.
Our rainfall, cooler summers and long growing seasons allow the plants to develop steadily without the intense heat stress they might experience in warmer regions.
Most importantly, the oldest specimens have been allowed to remain in place for generations.
Rhododendrons are often pruned or removed from private gardens when they become too large. In the Dell, they have been given the time and space to reach their natural height and spread.
The result is not simply a collection of flowering shrubs. It is a rhododendron forest.
A collection more than a century in the making
Planting in the Rhododendron Dell began in 1914 under the supervision of David Tannock, one of the most influential figures in the history of Dunedin’s public gardens.
By 2008, the plantings covered approximately four hectares and included around 3,500 rhododendrons representing 180 species and more than 200 hybrids.
The collection includes plants originating from different parts of Asia and the wider world, together with historically important cultivated varieties.
One particularly special plant is Rhododendron ‘Marquis of Lothian’, one of New Zealand’s oldest locally raised rhododendron hybrids. It was developed near Dunedin at Fairfield during the late 1870s by nurseryman William Martin.
This means the Dell does not simply display plants introduced from overseas. It also preserves part of Otago’s own horticultural history.
The giants called ‘Halopeanum’
Among the most impressive plants in the Dell are two old specimens of Rhododendron ‘Halopeanum’, also known as ‘White Pearl’.
They are believed to be among the earliest rhododendrons planted in this part of the garden and are now more than eight metres tall and approximately 11 metres across.
Those measurements are impressive on paper, but numbers do not capture what it feels like to stand beside them.
Their trunks divide into heavy, twisting branches that support a huge rounded canopy. When flowering, pink buds open into pale blossoms that gradually fade towards white.
The Dunedin Botanic Garden describes their combined floral display as resembling a cumulus cloud resting at ground level.
That is exactly the impression they create: a great white cloud of flowers held above thick trunks and sinuous branches.
Visitors often stop talking when they first see them. Even after flowering finishes, the plants remain impressive because their scale and structure reveal why rhododendrons have traditionally been called the “king of shrubs.”
The flower that waits up to seven years
The rhododendrons are not the only plants creating the Upper Garden’s Jurassic atmosphere.
The Himalayan giant lily, Cardiocrinum giganteum, begins its life looking surprisingly modest. For five to seven years, the bulb quietly gathers energy beneath the soil.
Then, when it is finally ready, it produces an enormous flowering spike that can reach two to three metres—and sometimes even higher.
Near the top appear large, creamy-white, trumpet-shaped flowers, often marked with purple inside. Their fragrance travels through the woodland before visitors have even located the plant.
After investing years of stored energy into this single performance, the main bulb dies. However, smaller offsets remain around it, beginning the long process again for a future generation.
There is something wonderfully dramatic about a plant waiting for years, flowering high above everyone for a brief period and then disappearing.
Pines that race towards the sky
Towering radiata pines add another layer to the Upper Garden’s sense of scale.
Pinus radiata comes originally from a small area of coastal California and a few nearby islands. In its native habitat, its distribution is limited. In New Zealand’s conditions, however, it grows remarkably quickly.
The trees rise above the garden like great columns, creating height, shade and shelter for the collections beneath them.
Together with the tree-sized rhododendrons, giant lilies and broad-leaved woodland plants, they create layers of vegetation—from the forest floor to the upper canopy.
This is what gives the garden its prehistoric feeling. No single plant creates the effect. It comes from being surrounded by vegetation at every height and in every direction.
The garden is never exactly the same twice
The Rhododendron Dell is at its most colourful during spring and early summer, but flowering times vary between species and cultivated varieties.
Some plants bloom early, while others wait until later in the season. One section may be covered in flowers while another is still holding tightly closed buds.
That uncertainty is part of the experience.
Even outside the main flowering season, the Dell remains worth visiting. The old trunks, enormous leaves, moss-covered branches and woodland atmosphere reveal a different kind of beauty.
On misty or lightly rainy days, it can feel even more like a mountain forest. Drops gather on the leaves, colours deepen and the twisting pathways seem to lead much farther from the city than they actually do.
More than a garden stop
For us at Fantail Tours, the Upper Botanic Garden is not simply somewhere to photograph flowers.
It gives us an opportunity to share several different stories: how Dunedin established New Zealand’s first botanic garden, why plants from the Himalayas and southwestern China thrive here, how some rhododendrons become forest trees and how the aviary contributes to native-bird conservation.
It is also a peaceful contrast to Dunedin’s architecture and busy city streets.
Within a short walk, visitors can stand beneath a rhododendron more than eight metres tall, discover a lily that waited seven years to flower and hear the call of a kākā from the nearby aviary.
You do not need to be an expert gardener to appreciate the experience. You simply need to look up.
Come and explore Dunedin’s Upper Botanic Garden and its remarkable plant giants on a Dunedin City Highlights Tour with Fantail Tours.
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