It's late July, the middle of summer. The flowering frenzy of springtime seems a long time ago, and there are still a couple of months to go until the glories of autumn colour return. But we're fortunate in Herne Hill to have a couple of exotic street tree species that are blooming right now.
The first is the hibiscus, sometimes known as Rose of Sharon, usually seen as a garden plant but hardy enough to thrive here as a small tree. We have four of these free- flowering Hibiscus 'Resi' clones. The first picture below was taken outside 31-33 Beckwith Road, where the well established tree bears deep pink flowers, some fully opened and others just emerging from the fat buds.
The photo on the right shows the contrasting lavender flowers that you can see on the pair of hibiscus in Delawyk Crescent, in the strip of grass at the side of no. 45. One of the Delawyk trees is thriving, the other struggling a little. Our fourth hibiscus, planted only last year and doing very well, is on Elmwood Road, at the side of 20 Wyneham Road.
Another favourite of ours is the tiny Persian silk tree (Albizia julibrissin) on Half Moon Lane, where it meets Village Way. Short, skinny and fragile-looking, and colonised every spring by brown scale insects (Parthenolecanium corni), this little tree still manages to produce a beautiful string of these delicate pink and white flowers in summer. Perhaps it yearns to grow up to be like its big, strong cousin in Dulwich Village, on the grass verge outside the Crown and Greyhound pub.
Elsewhere in SE24, away from this dazzling colour, our trees might look like they're in a bit of a lull at this time of the year, but in fact they're at a key stage in their life cycle: growing the fruit they need to spread the species. When people talk about 'fruit trees' they usually mean something you'll find growing in a back garden or an orchard, with a tasty crop can pick as the days grow shorter. But of course all trees bear fruit in one form or another - not all of it edible to humans.
On our streets you’ll see fruits known collectively as pomes, including apples, pears and hawthorns, which all carry multiple tiny seeds. You can also find stone fruit, like cherries, with a single hard stone at the centre, plus acorns and hazelnuts, winged fruit on maples and hornbeams, and rarities like the long, dangling seed pods of the Indian bean tree.
In simple terms, a fruit is the matured ovary of a flower. The ovary fills with seeds (or sometimes just a single seed) once the flower has been fertilised and it remains on the stalk after the petals and pollen-producing parts of the flower have fallen away. Most, but not all, tree fruits develop a fleshy outer case around the seeds.
But the mature fruit isn’t just a container for the seeds: it’s the instrument for dispersing them, allowing the tree to multiply in new locations. There are a number of ways this happens. Gravity is the simplest. A heavy fruit like a horse chestnut will simply drop to the ground when it’s ready, and the spiky case will split open from the force of the impact. If the squirrels leave it alone the nut will sprout in the spring.
The wind can help too, blowing the light, papery fruit of trees such as the sycamore further away from the parent tree. Birds are also great allies. They’ll eat the berries and spread the seeds in their droppings, but jays will bury acorns and sometimes forget where they are, allowing them to germinate. Squirrels, of course, do the same with acorns and hazelnuts.
Sunray Avenue, our urban orchard
Sunray Avenue is the place to find edible fruit trees, but we would ask you not to pick any unless you belong to one of the residents’ groups looking after them. There are three locations, all on grass and all on the eastern (odd-numbered) side of the street.
Starting from the roundabout at the bottom of the hill, you’ll come first to a charming little square on the right, directly opposite the Cassinghurst flats, with four mature apple trees inside. It’s bounded by a neat hedge and has Arts and Crafts-inspired cottages on three sides, nos. 83 to 111 Sunray Avenue.
Further up, directly after the junction with Nairne Grove, there’s a much larger green between 49 and 71 Sunray. You can't miss the two big oaks at the front, just by the pedestrian crossing where Casino Avenue intersects with Sunray. It’s an attractive space, well worth visiting. The grass is being left to grow long this year but paths have been mown through the fruit trees: a quince, a medlar, a pear, three cherries, three mature apple trees and two more apples planted last December.
More fruit trees on Sunray and Casino
If you want to see more fruit collections walk to the very top of Sunray, just before it joins Denmark Hill, and you’ll find a new pocket orchard in the grounds of the Hillcrest estate. We wrote earlier this year about the eight new fruit trees - little one-year maidens - planted there in January. You can see the four apples and four pears on the lawn between two blocks of flats, nos. 16-30 and 31-45.
A month later three more fruit trees, also one-year maidens, arrived on another garden square on the Sunray Estate, outside the Casino flats. There were a pear and two plums behind the hedge, near a revived old ginkgo stump in the corner, although sadly the pear has since died.
Let's have a look at some of these edible fruit species found along Sunray and a couple of others you can see on the nearby streets.
The medlar
The Sunray medlar is easy to find: step on to the grass from the zebra crossing and it's the first tree you'll come across. We sang the praises of medlars in July 2022, but this one was planted very late in the season and suffered badly in the drought and extreme heat of last summer, losing most of its leaves. This year the foliage is back but at the time of writing there weren't any fruit on the branches.
However, there's a new medlar in town, at the bottom of Hollingbourne Road alongside 15 Warmington Road. Planted just seven months ago, it's being looked after by neighbours and is doing exceptionally well, with a lush canopy of glossy leaves and an impressive crop of fruit.
Not many of you will have tasted a medlar and they're not something you can just pluck off the tree in autumn and bite into. They're tough and impossible to eat until they've hung on for a few more months when they begin to rot - a process called bletting. Cold winter nights will turn the flesh soft and bring out the sugars, but even then you're more likely to see them in a jar of medlar preserve than on the greengrocer's shelves.
The quince
You might, though, see a golden yellow quince for sale in October or November. Like the medlar, the fruit is hard and you can't eat it raw, but you can make it into jams and jellies or stew it until the flesh turns pink. The common quince (Cydonia oblongo) on the Sunray Avenue is near the medlar, but closer to the first house on the green, no. 49. It's been there just over two years and looks happy.
Both the medlar and the quince were much more familiar in mediaeval times, when other sweet fruits were scarce during the winter months.
The pear
Nowadays quince trees serve another important function: in commercial nurseries they're grown as rootstock for cultivated pears. What this means in simple terms is that the grower takes a small cutting from a pear tree with a few buds on it (the scion) and splices it into the base of a young quince stem with roots attached (the rootstock). Grafted pear trees are easy to propagate, grow small enough to make picking easy and produce good yields much earlier than a pear tree with its own roots.
All the pears planted this year in the Hillcrest and Casino housing estates were on the most widely-used rootstock, called Quince A, and the little conference pear (Pyrus communis 'Conference') growing in the Sunray Avenue green will have been similarly grafted. Here's a picture of those delicious-looking conference pears, alongside one showing the much smaller, rounder fruit from the ancestor of all cultivated pears, the common pear (Pyrus communis).
We've got three of these common pear trees on the streets of Herne Hill: one on Ruskin Walk, one on Warmington and one on Burbage Road. It's probably fair to say that they're not popular with residents. They produce large quantities of sour, often mouldy fruit that carpets the pavement below during August and September and have no autumn colour to speak of.
A much better pear tree for cities is the more shapely Callery pear (Pyrus calleryana), which produces brown fruits that are so small that they're difficult to spot when the tree is in leaf. The 'Chanticleer' variety is one of our commonest trees and is probably found on more streets than any other, but the 'Redspire', which you can see on Stradella Road and Wyneham Road, has much finer autumn colours. Pear blossom tends to be overshadowed by the cherries of Herne Hill, but the Callery pears and the common pears both put on an great display this spring.
The apple
Back on Sunray, the two new apples, planted in line with the medlar, are worth a look. You can spot them by their tree cages (the three older apple trees are over by the hedge). They're both well known varieties: a Golden Delicious dessert apple (Malus domestica 'Golden Delicious') and a Bramley cooking apple (Malus domestica 'Bramley's Seedling'). The Bramleys are already considerably bigger than the Golden Delicious.
We also have a pair of John Downie crab apples (Malus 'John Downie') on Burbage and a couple of Chonosuki crabs (Malus tschonoskii), one on Burbage and the other on Frankfurt Road. The Chonosukis are tall and columnar, and have superb autumn colours, but the smaller, untidier John Downies are among the best for making crab apple jam and jelly. Their abundant fruit will soon turn a very pretty red, yellow and orange colour and persist into the colder months.
The rowan
There's one more tree - at least the wild species, found in the uplands of Britain - that can also be used for jelly and that's the native rowan or mountain ash (Sorbus aucuparia). You can't eat the berries raw, although they're irresistible to birds. Rowans generally have a poor survival record on Herne Hill streets but there is a big, healthy specimen in the hedge at 77 Casino Avenue, just three doors away from a similar tree that died a few years ago.
The council stopped planting rowans for a while but in December a new one appeared at 65 Ruskin, a yellow-berried Sorbus x arnoldiana 'Schouten'. The supplier, Barchams, describes it as a "tough and reliable clone", so it should have more success than its predecessors.
We haven’t covered here the other members of the Sorbus family that we find in Herne Hill (the whitebeams and service trees) but we plan to revisit these in the autumn, when their fruit will have coloured to red and orange. The same goes for the hawthorns (Crataegus) and also the oaks (Quercus), whose acorns are yet to appear.
Nut trees
There's one category of fruits that we haven't looked at yet: nuts. They're undoubtedly fruits, just not the fleshy type. "Nuts are actually fruits," the U.S. Forest Service says. "They are defined as dry, single-seeded fruits that have high oil content. They are usually enclosed in a leathery or solid outer layer." Almonds don't qualify as nuts because they've got a fleshy coat like a plum, and nor do peanuts - they're legumes and grow under the soil.
The hazelnut
We've got six trees bearing hazelnuts, familiar from chocolate bars and Nutella spread. Four of these are the Turkish hazel (Corylus colurna), introduced into the UK over 400 years ago. This tall, handsome street tree has long yellow catkins in spring, nuts concealed in a coat of long, curling tendrils in summer and craggy, corky bark all year round. You can find it on Danecroft Road, Casino, Holmdene Avenue and Beckwith Road where it joins Red Post Hill.
The native common hazel (Corylus avellana), meanwhile, is much shrubbier, particularly if it's been coppiced. This is an ancient wood management technique, where the trunk gets cut back almost to ground level, stimulating thick, fast-growing new branches to grow. You can find a pair of these trees at the back of the Sunray green space, in front of nos. 59 and 61. Their nuts are smaller than their Turkish counterpart but they open sooner.
Both the Turkish and the British hazelnuts are edible but better roasted than raw. They'll be ripe in September and October.
The walnut
The last edible fruit (or nut) on our menu is the walnut (Juglans regia), known as the English walnut although it was actually introduced by the Romans (who also brought the medlar). Our only specimen is on the front lawn at Delawyk Crescent, near house no. 60, a splendid tree though still rather small. The big green fruit can grow up to 2 inches (5 cm) long and the leaves, each made up of seven or so 'leaflets', can reach up to 18 inches (45 cm).
The horse chestnuts
Now for something completely inedible: the horse chestnuts (Aesculus). We've got three species in Herne Hill, all of them toxic to humans, although not to squirrels. Their leaves and their fruit make them easy to distinguish from one another.
The first, the common horse chestnut (Aesculus hippocastanum) is the classic conker tree, far bigger than the other types. The big, dark leaves, made up of five or seven leaflets, emerge very early in the spring from enormous, sticky red-brown buds, and the green fruit, armed with sharp spines, drop to the ground in September and break open to reveal the shiny, mahogany-coloured nut within. The tree pictured on the left is in the grounds of the Delawyk estate, overhanging the pavement of Half Moon Lane from just behind the fence.
But the common horse chestnut is highly susceptible to disease and Dulwich has lost several in recent years. It's rarely planted nowadays, although we do have two youngish specimens in the lower cul-de-sac on Casino Avenue.
Instead, Indian horse chestnuts (Aesculus indica) and red horse chestnuts (Aesculus x carnea) are now becoming much more common on our streets. You can see Indica in the cul-de-sacs of Sunray and Casino, and also on Stradella where it meets Burbage. The leaves, hanging on red stalks, are glossier, narrower, paler and smoother than Hippocastanum, and the fruit are pale brown and completely smooth-skinned. The picture on the right shows them just beginning to develop in July, on tall stalks rising above the canopy, but these photos from last autumn show how they will look in three months' time.
Finally, the red horse chestnut. This hybrid has leaves that are very similar to Hippocastanum, one of its parents, although glossier, and its fruit also shows features of the conker but with much smaller spikes. The photo below shows a very fine Aesculus x carnea on the front lawn of Delawyk Crescent, beside no. 107. There are two other Carnea on Herne Hill, at the corner of Casino and on the side lawn of the Denesmead estate; two more in the cul-de-sacs of Casino and Sunray; and a fifth in the grounds of Carterscroft, on Red Post Hill.
The roasted chestnuts that you could traditionally buy from from street vendors during wintertime come from a totally different tree, the sweet chestnut (Castanea sativa). Brought to Britain by the Romans, you can now get them from supermarkets, ready to roast at home. Sadly we don't have any sweet chestnuts in Herne Hill, other than one in Sunray Gardens and others in people's gardens. They're very beautiful, but more of a tree of parks and woods than a street tree.
Flying fruit
Now to a group of trees with fruit that spins slowly through the air as it falls, dispersing the seed away from the mother tree.
The maples
This is a characteristic of the maples (Acer) in particular. The fruit of the young Norway maple (Acer platanoides) below, in the top cul-de-sac on Casino, is known as a samara. It consists of two papery wings, each wing carrying a single seed. The fruit hangs on the tree for several weeks in big bunches as the seeds mature and in autumn it falls, spinning as it descends and generating lift in a process called autorotation. When the wind catches it in flight it can travel a long distance from the parent tree, enabling the species to spread more widely.
One maple that's done that very successfully is the sycamore (Acer pseudoplatanus), which is not a native tree but has become naturalised all over Britain. The wings of the sycamore meet at an angle of nearly 90 degrees, unlike the Norway maple, where it's more like 180 degrees.
The hornbeam
Children like to call these samaras 'helicopters' and you can see them on the native common hornbeam (Carpinus betulus) too. Hornbeam fruit start as pollinated female catkins, so these lovely trees are decorated with exquisite hanging ornaments through spring and summer. This samara is from one of the two mature hornbeams in the Casino garden square, between the flats. They were joined there last year by a new sapling, but you can also find five hornbeams on Sunray - two in the stretch of road that leads into Crossthwaite Avenue and three in the cul-de-sac between nos. 20 and 42. Burbage and Stradella also have one hornbeam each.
The lime
Lime tree fruit also autorotate, but their design is slightly different. Instead of samaras, the five very unusual Mongolian limes (Tilia mongolica) on our stretch of Burbage use single bracts to keep them in the air so that the wind can carry them further.
Bracts are actually modified leaves and serve many other purposes. In some trees like the dogwoods (Cornus) and the dove tree (Davidia involucrata) they look like petals and attract pollinators.
The American sweet gum
Finally, from one of the rarest trees in our area to one of the commonest - the American sweet gum (Liquidambar styraciflua). You’ll be familiar with this medium- to large-sized tree from its bright green “palmate” leaves, like some maples, resembling the fingers of a hand. The long-lasting autumn colours - yellow, orange, crimson and purple - are a breathtaking sight.
But look among the thick foliage in summer and you’ll spot little spiky green globes, the Liquidambar fruit. Seen through a telephoto lens they look like something out of science fiction. Each of those spikes was a tiny female flower that's developed into a capsule holding one or two seeds.
There are dozens of capsules in each fruit ball, and when they open in September the seeds are dispersed by the wind or eaten by birds. The sweet gum fruits, now seedless, turn dark brown, hard and spiny over the winter and stay on the tree throughout the spring, when they share the branches with the new green crop.
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