September 2025: Weird magnolias
- hhtreewatch
- Sep 8
- 11 min read
Updated: Sep 10
This year's hot and dry spring and summer have put our street trees under enormous stress and we're now seeing their response: a 'false autumn', weeks ahead of its usual appearance. The combination of enduring heat and drought have brought some of our trees almost to the limits of their endurance. We've seen leaves shrivel up and fall to the ground, or start flying their autumn colours in late August like the American sweet gums (Liquidambar styraciflua).
At the same time there's been a big crop of very early fruit. In some parts of London acorns have been crunching under commuters' feet since early August and blackberries have long since disappeared from the hedgerows. But it's a false autumn because trees aren't yet actually dormant and are still capable of growth if the conditions are right. In fact you might have seen fresh leaves and shoots emerging with the recent cooler and wetter weather.
As the Met Office puts it: "Drought conditions cause trees to enter a kind of survival mode, dropping their leaves early to preserve themselves for the rest of the year and beyond. While the trees aren’t dying, they’re not thriving either, and the early leaf fall is a sign of the stress caused by the summer’s extreme conditions."
Frank P Matthews, a big Worcestershire tree nursery, explains the glut of fruit: "When conditions become too harsh, many trees and shrubs react by shutting down, shedding leaves, and fast-tracking fruiting. It’s a survival mechanism. The trees' way to conserve energy and ensure reproduction [is] by pushing out seeds and berries before it’s too late."
Interestingly, one of the street trees that's produced far more fruit than we've seen before is a genus that we don't associate with fruit at all: the magnolia. We admire them for their luscious flowers in early spring, of course, but who knew magnolias have fruit too? We'll be looking at their very strange fruit a little further into this blog, but first here are a few snapshots taken last month of our false autumn in Herne Hill.
Berries
Pictured on the left, below, is one of our favourite trees, the broad-leaved cockspur thorn (Crataegus x prunifolia), showing off its rapidly ripening haws and its glossy leaves changing colour in a front garden on Burbage Road. The many hawthorns on the streets of Herne Hill have come through this year virtually unscathed and there are plans to plant many more of this drought-tolerant genus in the years to come.
The second photo shows the gleaming yellow berries of a young rowan, or mountain ash, outside 65 Ruskin Walk. Rowans and some other members of the Sorbus (or whitebeam) family don't have a great record in the area when they're planted on the pavement, but this hybrid, Sorbus x arnoldiana 'Schouten', seems to be thriving.
Yellow leaves and fruit
The tree below on the left is a Snow Goose cherry (Prunus 'Umineko') just up the hill from no. 8 Ruskin Walk. It's looking rather fine in its autumn-like cloak but its immediate neighbour, another Umineko, had a catastrophic summer and is now almost certainly dead. We wrote about it in August, and since then its condition has worsened. The intrusive thistles we pulled out of the tree pit have grown back stronger than ever.
Next to the cherry is a fruit you rarely see growing in a public place: it's a quince from the tree planted in the big open space on Sunray Avenue. If you're coming from Casino Avenue the quince (Cydonia oblonga) is the second tree you'll come across if you're walking along the left-hand boundary. It's a self-pollinating species, so you only need one to grow the large fruit, which is bitter raw but sweeter after cooking.
Chestnuts
The chestnuts have had a good harvest too. The thousands of conkers from our big common horse chestnut trees (Aesculus hippocastanum) have now all dropped and split open, but the similar-looking spiky shells of the sweet chestnut fruit (Castanea sativa) in Sunray Gardens are still going strong. The two trees are actually only linked by their vernacular names and are botanically unrelated. The sweet chestnut, which is edible, is closer to the oaks and beeches. You'll find our large and lovely local tree, with its long, glossy leaves, on the lawn just inside the gate into Sunray Gardens from Red Post Hill.
Our modern disease-resistant horse chestnut variants are still cropping steadily as well. One of those is the Indian horse chestnut (Aesculus indica) which bears spikes of small, smooth-skinned brown nuts. The one pictured is on Stradella Road where it meets Burbage Road. The fruit of the red horse chestnut (Aesculus x carnea) is similar to the Indica, but the leaves are much closer in appearance to the common horse chestnut.
Hazelnuts
Here's an edible nut tree that you can find on Holmdene Avenue, Danecroft Road and - this one - at the junction of Elmwood Road, Beckwith Road and Red Post Hill. It's the Turkish hazel (Corylus colurna), a robust and drought-tolerant tree that deserves to be planted more widely. In January this medium-sized tree bears long, yellow male catkins and in the summer these green husks with writhing tendrils appear. Inside each is a little brown hazelnut, flatter than the ones you can buy in the supermarket. Judging by the numbers of nuts on the pavement, the 2025 crop was bigger than normal.
Apples
A buyer from Waitrose told The Guardian a couple of weeks ago: "We’ve got an early start to the apple season this year, all thanks to ideal spring conditions and a warm temperature throughout the growing season accelerating the ripening process for many fruits, like apples.” That's certainly been the case with our local crab apples. The John Downie crab (Malus 'John Downie') below looks like it's had an amazing summer, its boughs literally weighed down with red and yellow fruit. It stands outside 50 Stradella Road. There were two other John Downies on Burbage Road until autumn 2024, when the one at no. 62 was felled. The fruit can be made into jam or jelly.
On the right is a big Golden Delicious apple grown in the middle of the Sunray Avenue green space. The tree (Malus domestica 'Golden Delicious'), planted in December 2022, looks like it's had a decent crop this year. A few yards away, towards the main road, is a Bramley cooking apple (Malus domestica 'Bramley's Seedling'), which is less vigorous.
Fungi
These next fruits are definitely NOT for eating. We might not think of them in the way we do apples and oranges, but bracket fungi like the ones below are known as the 'fruiting bodies' of organisms that feed and spread deep in the wood of trees. Like tree fruit, these mushroom-like growths are designed for reproduction and contain billions of spores that will disperse on the wind and germinate on decaying wood. The brackets grow a new layer every year and release their spores in the summer.
The multi-tiered bracket is on a Kanzan cherry (Prunus 'Kanzan') at 40 Stradella Road. The pancake-like bracket is on the only remaining John Downie crab on Burbage Road, at no. 52. Unfortunately these fungi often signal that the tree host will soon be felled by the council.
The weird and wonderful fruit of the magnolia
Just as bizarre as a wedding cake-shaped fungus or the octopus-like tentacles of a Turkish hazel is the otherworldly fruit of the magnolia. When we first started Herne Hill Tree Watch, back in 2019, it was one of our missions to fill the almost barren slopes of Casino Avenue with magnolias, and now there are 28. They're rightly admired for their gorgeous springtime flowers, but at the time we knew nothing about their strange fruit. We first noticed them in autumn 2021, but only on three or four trees. This year though, in the face of danger from the intense heat and drought, the magnolias have been urgently producing fruit and seeds to make sure the lineage continues. We found fruit on 14 of the Casino magnolias by late August 2025, but they're small and almost buried in the dense foliage, easily missed by passers by. Take a look at the crown of this tree at 32-34 Casino.
Can you spot the little red dots? There are dozens, maybe hundreds of them, but to see the detail you'll need good eyesight and a telephoto camera lens or powerful binoculars. Here's a close-up shot of the same tree (32-34) on the left and another at no. 96.
Now you can see why we called the fruit "weird" and "otherworldly". It's totally unlike any other familiar tree. The reasons for that go back in time. A little bit of botanical science will help interpret what we're looking at.
A bit of botany
The first thing you need to know about magnolias is that they're very ancient and very primitive plants. The fossil record shows that they evolved about 95 million years ago, in the Cretaceous period, about 30 million years before the dinosaurs became extinct. Among Earth's living trees only the ginkgos, whose ancestors appeared over 200 million years ago, are older. So the magnolia's reproductive system - which determines the appearance of the fruit - is very unusual.
First, magnolias made their debut long before bees existed, so they're pollinated by flightless beetles. Nowadays bees and other pollinators will also visit the flowers, attracted by the bright colours and the scent, but the beetles remain the primary provider of pollination services. Magnolias also don't produce nectar, so the beetles feed on pollen instead. But with their sharp mandibles - powerful cutting jaws - they're also capable of snacking on other tasty tree parts. To prevent injury, the magnolia's carpels, the female reproductive organs at the centre of the flower, are toughened. The leaves are thick and leathery. The petals have merged with the more robust sepals (the outer covering of the flower bud) to form what's known as tepals. And the fruit is armoured by a protective shell.
Here's another unique quality of the magnolia: during the day, beetles bring pollen from other magnolias into the flower. At night the tepals close, and any beetles still there are trapped inside the flower, where they deposit pollen on to the stigmas, the tips of the female carpel. The stigmas then shut down and the anthers, the pollen-producing part of the male stamen, become active. The beetles now pick up fresh pollen from the anthers and in the morning, when the flower opens up again, they crawl out in search of another magnolia to drop off their gift of pollen and start the cycle again.
We've missed this phase of propagation on Casino Avenue, where the fruit is already ripening, but over on the Pynnersmead estate, at the foot of Herne Hill, there's a solitary evergreen Southern magnolia (Magnolia grandiflora) on the side lawn where the multiple carpels have fused into this woody cone. The stalk is what remains after the stamens and the tepals have fallen away.
Each of those little spikes on the surface of the Pynnersmead fruit is a carpel, and each of the little mounds beneath them is a developing seed. The seeds live in cavities called follicles and the case, or pod, that holds them together is known as a follicetum. Eventually this follicetum will dry out and split, revealing the orange-red seeds within. The seeds will hang from a tiny thread until they're taken by birds or other creatures.
You can see the skeleton of an empty Southern magnolia fruit in the picture below, taken last April on Howletts Road where it had fallen from a big tree in a neighbouring back garden. The cavities where the seeds had been are clearly visible.
Now back to Casino
Let's see how all this applies to the magnolia fruits on Casino Avenue. Still at no. 96, zooming further into the high branches, you can see the growing magnolia fruit in more detail. Each of those round red blobs, arranged in a spiral pattern, is a seed, each seed is developing in a follicle, and the lumpy red pods holding all the seeds and follicles are the follicetums. There are three follicetums in the photo below, each a different shape and each formed from a different flower.
Here's a follicetum that's fallen to the ground opposite 91 Casino. It hasn't completely split open and you can see a few of the bright seeds still in their individual cavities.
Below are a couple of other fruit shapes, both on the tree at 97-99 Casino. In the photo on the right, the red 'tail' is made up of follicles that haven't been fertilised and haven't developed into seeds.
This next pod of magnolia seeds, at 100 Casino, has developed a kink.
The pods come in various colours as well as shapes. The unripe pods are green, like this one at 97 Casino.
On the same tree, at no. 97, you can also find semi-ripe pods like the two below. The first pair have just a blush of pink, while the more developed pods in the right-hand picture have lost almost all of their baby colour.
Still at 97 Casino, these hanging bunches of almost ripe seed pods are approaching their eventual deep crimson shade.
And finally, one more feature we haven't mentioned up to now: the tiny white speckles that you get on this type of magnolia fruit. This pod looks like a cross between an exotic tree frog and a poisonous fly agaric mushroom, and it's yet another example of the uniqueness of this amazing tree.
Which species of magnolia are these trees?
You'll have noticed that up to this point we haven't mentioned the species of the fruit-bearing trees on Casino Avenue. There are over 200 different species of magnolias and countless more variations, so it's hard to be certain when they don't have their original labels from the tree nursery. But if you check any of the photos above on the PlantNet identification app it comes up with Magnolia kobus (northern Japanese magnolia) at 80-90% certainty.
That was already our guess, since we knew that Southwark Council plants M. kobus and the small while flowers alone pointed us in that direction. But there's an outside chance that this or other white magnolias on Casino could be Magnolia loebneri 'Merrill', a cross between the kobus and Magnolia stellata, the star magnolia. We hope to confirm the name when we a take a close look at all the flowers in the spring.
In the meantime, here's our provisional list of the different types of magnolias that you can find on Casino Avenue, with the numbers of the nearest houses. We're pretty confident about the 14 northern Japanese, the only trees that are actually growing fruit at the moment. We're certain about the nine Heaven Scent magnolias - they were all planted with labels attached in December 2022, apart from the one at 51/53 Casino (April 2023). And we've identified the four Galaxies by their large, showy, dark pink flowers. Which leaves only one puzzle, at no. 60, which we think is probably a Merrill. But we'll get back to you on that in a few months.
Odd side (14 magnolias)
Heaven Scent magnolia (Magnolia 'Heaven Scent'): eight trees
47
51-53
87-89
119
121-123
125-127
129-131
133
Northern Japanese magnolia (Magnolia kobus): four trees
Side of 53
97
97-99
105
Galaxy magnolia (Magnolia 'Galaxy'): two trees
7 (opposite 8)
93-95
Even side (14 magnolias)
Northern Japanese magnolia (Magnolia kobus): 10 trees
Hedge, side of 29 Herne Hill
30
32-34
Opposite 91, on pavement
96-98
100-102
116 (nearest Red Post Hill)
116 (nearest 118)
118-120
124
Galaxy magnolia (Magnolia 'Galaxy'): two trees
104-106
112
Heaven Scent magnolia (Magnolia 'Heaven Scent'): one tree
84, corner of square
Merrill magnolia (Magnolia loebneri 'Merrill'): one tree
60
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