May 2025: Another side of spring
- hhtreewatch
- May 2
- 12 min read
Updated: May 14
As you might imagine, the work involved in compiling and updating the guides to every tree on every street in the Southwark half of Herne Hill has preoccupied us for the last few months, which is why you haven't seen a pictorial blog for a while. We wrote about our findings in the April blog.
Now that we can catch our breath we've gathered a few images and written down a few thoughts about some of the spring features that we might have been neglecting, like bark, buds, branches and emerging leaves. If you're still hankering after photos of spectacular blossom have a look at the flower diaries that we published last year, which tell you month by month what to expect. There was one for spring blossom in May and one for summer flowers in September.
First of all, though, a few words about the latest plantings.
New arrivals
We saw a disappointing number of trees planted in the season ending March 31: just 20, sharply down on previous years. The council said planting on housing estates had been the priority in 2024/25 and street tree plans had to be scaled back. Thirteen of the new trees we'd been expecting have now been deferred - two each on Casino Avenue, Delawyk Crescent, Elfindale Road and Sunray Avenue, and one apiece for Burbage Road, Frankfurt Road, Half Moon Lane, Red Post Hill and Warmington Road.
You can see the details of all the new trees in this table. Among the highlights are:
A wild service tree (Sorbus torminalis) in Casino Avenue. We had a few specimens of this rare native on the Delawyk estate a few years ago, but none of them thrived, so we'll be looking closely at this one's progress.
An evergreen Atlantic cedar (Cedrus atlantica) and a deciduous Turkey oak (Quercus cerris) on Red Post Hill, both potentially big trees.
Two Tibetan cherries (Prunus serrula tibetica), one on Delawyk and the other Stradella. These have glossy, mahogany-coloured bark, but to look their best you have to stroke them gently, keep the trunk clear of side buds and avoid too much pruning, which can lead to wounds that don't heal. Fortunately both the newcomers are a good size and shape already.
Future planting plans
To restore the momentum that we'd previously achieved, we're planning to put in requests for a large number of new trees in 2025/26, as well as making sure all the deferred trees are planted and all lost trees are replaced. Planting will start around November and it takes a while for the tree officers to put in orders at the tree nurseries, so it's best to be early with our shopping list. We've already scoped out potential sites on all our streets and we'll be discussing them with our street leaders and volunteers over the next few weeks.
Start watering now!
March and April have been very dry and warm and there's very little rain on the horizon. Our new trees need lots of water so please keep an eye on them and give them a top-up if they're looking a bit droopy, or if the green watering bags are consistently dry. The same goes for all the trees planted in the previous couple of years. Basically anything that's still got a bag zipped around the trunk should be checked out.
The private companies that do the planting are also contracted to water and maintain the juvenile trees for three years, but we have to be on standby at times of persistent heat and drought to make sure they get properly established. Their harsh new urban environment is a far cry from the strictly managed nurseries where they've spent around seven years being cared for before being transplanted to the streets.
We've got all the information you need about how and when to water and how much young trees need to develop the deep roots that will keep them fed and toughen them up. Fifty litres a week is the baseline, and more in hot, dry weather. Even if it does rain, saplings can't rely on rainwater to give them the moisture they need. It runs off the pavement into the gutter and evaporates before it reaches well into the soil.
Just click on the WATERING tab at the top of your screen to find out more. Your street leader will help you out too. Make sure you get in touch with them to let them know you're available. We'll send you their names and contact details in an email shortly.
Spring picture postcards
That's the housekeeping out of the way. Let's now have a quick run through of things that have caught our eye in the last few weeks: some oddities, some perennials, and some new sights.
Bark and branches
The birches are pretty slow at coming into leaf, so when the sun is out and the sky is blue their white bark really stands out. We've got a lot of brilliant white Himalayan birches (Betula utilis jacquemontii) in Herne Hill and also many native silver birch trees (Betula pendula), some of which are coming to the end of their lives. But there's only one paperbark birch (Betula papyrifera), this one outside 165 Half Moon Lane.
It's a big, sturdy tree and the shaggy, peeling bark is worth a look. In the northern U.S. and Canada, where the tree originated, indigenous peoples would stretch the tough, lightweight bark across a wooden frame to make their unrivalled canoes.
On clear spring and autumn evenings, when the sun is low in the western sky, the two Himalayan birches at the foot of Ruskin Walk get their own chance to shine as their branches cast crisp shadows on the white side wall of no. 1 Warmington Road.
Halfway up Frankfurt Road, on the odd side, there's another interesting pair of trees: two Chanticleer pears (Pyrus calleryana 'Chanticleer') with extraordinary spiral bark, unlike their plainer cousins which you see all over Herne Hill. It's a genetic feature which is said to give the tree greater flexibility and wind resistance - and it always grows in an anti-clockwise direction.
The bark of the crape myrtle (Lagerstroemia indica) is also worth a look. These trees are known for their amazing late summer flowers, but their bark is also eye-catching. It peels off in tight curls in springtime to reveal fresh new wood in shades of pink, cinnamon and ginger.
We've had a surge of crape myrtle plantings in the last couple of years: two on Elfindale, two on Danecroft and one on Frankfurt, in addition to an older, but less robust example on Delawyk Crescent. Their resistance to drought could make them a good bet for the future.
Spring branches
The absence of leaves in early spring can really make you appreciate the shapes and silhouettes of the bare branches. The mature broad-leaved cockspur thorn (Crataegus x prunifolia) in the cul-de-sac at 7 Casino Avenue has a graceful and sinuous outline, unlike many hawthorns which can look scrappy and ragged in winter.
By contrast, our many ginkgos (Ginkgo biloba) grow ramrod straight, with their lateral branches jutting out in geometric patters and their stout, knobbly buds marching along them in strict formation. The tree above, one of four at the top of Frankfurt Road, is among the biggest in the area. As the fan-shaped leaves begin to emerge they seem to make this living fossil, with its primordial features, look even more alien.
Spring buds and leaves
Watching buds swelling is another of the pleasures of springtime. Whether they go on to produce leaves or flowers, they're another welcome sign of the end of winter. We're fond of the bright crimson buds of lime trees and the plump sticky buds of horse chestnuts, but beech buds are among our favourites. They start off very narrow and sharply pointed, but once the sap starts flowing they quickly grow fat and wide, like this young Zlatia beech (Fagus sylvatica 'Zlatia') on Sunray Avenue, outside block 1-15 of the Hillcrest flats. It's one of only three street beeches in Herne Hill. The other two are weeping beech (Fagus sylvatica pendula) on Danecroft and Elfindale.
Bigger still than the Zlatia beech are the buds on the four little sycamores of Nairne Grove, planted two and a half years ago. These trees are mop-headed grafts on a short sycamore stem and will never get big, unlike their semi-wild ancestors, but their buds and leaves are still adult sized. They're a cultivar called Acer pseudoplatanus 'Brilliantissimum' and their leaves emerge the colour of cooked shrimp or salmon fillets, depending on your culinary taste. Later in the season they'll turn a pleasing yellowish green.
To give you an idea of their size at maturity, the pink-leaved mini-sycamores pictured in Perth were planted more than 40 years ago and they're barely twice the height of the park sign behind the railings. Six metres is their absolute maximum in perfect conditions.
Here's a tree that is almost perfect for the city: attractive, medium-sized, a native species that's wildlife-friendly, interesting all year round. It's the whitebeam (Sorbus aria), and like all the Sorbus family it's drought-tolerant. It also seems to flourish on our streets, and there are arguably too few of them in Herne Hill.
The one pictured on the left is at 66 Ruskin Walk, where it holds its own despite being overshadowed by a very fine Paul's Scarlet hawthorn (Crataegus laevigata 'Paul's Scarlet') in a neighbour's front garden. The fresh young leaves of the whitebeam open before the flowers but at a distance, in the spring sunlight, they can almost be mistaken for flowers themselves. They stand very erect, like tulip petals, and the pale underside of the leaves appears almost white.
There's another excellent whitebeam on the lawn outside the United Church at the top of Red Post Hill, and others next to 17 Nairne Grove and at 80 Holmdene Avenue.
A tall, straight, newly planted tree outside 195-197 Half Moon Lane, just before it meets Red Post Hill, had us baffled for a while. It was missing its label and the small buds were too high to identify. We wondered if it might be a lime, which has similar alternate buds, meaning they grow singly - one on one side of the twig, the next a short distance away on the other side. Maples, sycamores and many other trees are different: their buds, leaves and twigs are opposite and they always grow in pairs.
The unfolding leaves on the mystery tree were very small and nothing like a lime: narrow and pointed, with deep serrations. It took a few more days to figure out that it was in fact a zelkova, a close relative of the elm. The precise species is Zelkova serrata, commonly known as a keaki or Japanese zelkova. We've got two more of these interesting trees on Red Post Hill, at 42-44 and 54, planted in 2021 and still fairly small. The first of these turns a subtle shade of red in autumn, the second a stunning lemon yellow.
Elsewhere on Red Post Hill, in a grass verge just before you reach Denmark Hill, stands a genuine lime tree, a Tilia cordata or small-leaved lime, pictured on the right. The cordata in the name means heart-shaped - a very accurate description of the leaf. It's a fine woodland tree, native to Britain, and you'll often see it in planted in columns along the drive up to a stately home or in royal parks.
Uninvited spring guests
Here are a couple of curiosities spotted on our walks: two plants that have taken root in other trees. The first photo below shows some kind of shrub growing in a cavity in the trunk of a large old London plane (Platanus x hispanica) on Nairne Grove. The cavity might be a sign of decay, where rotting wood provides a rich enough planting medium for a seed to grow.
The photo alongside shows a thriving little yew tree (Taxus baccata) that's made a home in the stump of an old ginkgo in the garden square outside the Casino Avenue flats. The seed was probably dropped here by a bird after eating a yew berry and decaying matter inside the stump gave it enough nourishment to germinate and grow. The stump itself has regenerated and its coppiced branches now reach up into the telephone wires above. Now it's a question of which tree eventually wins out here: the yew or the ginkgo. Either way, we definitely don't want the stump to be removed.
Spring fruit
We're so familiar with the London plane - the commonest tree in Herne Hill - that we probably don't notice many of its features as we hurry past on the way to the shops or the station. There's the camouflage-coloured peeling bark and the maple-like leaves, of course, but the fruit is often hidden high in the canopy. Luckily the young plane at 69 Half Moon Lane, planted only in 2024, has given us a fine crop that's stayed on the branches right through the winter.
These spiky brown bobbles, each about an inch (1.5 cm) across, will start to crumble soon, each dispersing hundreds of seeds. But at the same time this year's fruit is starting to develop. It begins as a small, crimson, globe-shaped female flower, as you can see in the picture below, taken on Sunray Avenue.
There's another fruit that's easy to miss: the cherries on our famous Yoshinos (Prunus x yedoensis). The right-hand photo above shows how these form and swell once the exquisite white flower petals have blown away. The blossom itself is rightly admired in early spring, whether in the ranks of Yoshinos along Winterbrook Road and Stradella Road or the individual trees appearing on many of our smaller residential streets. And the lovely orange and brown leaf colours make a fine autumn display. But the small, glossy fruit deserves a mention too. Look out for it in June, when it will be bright red and yellow.
And now for something completely different. This weird-looking hand grenade is the dried-out fruit of one of Britain's most primitive, yet well-loved trees: the Southern magnolia (Magnolia grandiflora), an evergreen favourite of suburban gardeners. Magnolias date back to 95 million years ago so everything about them is unique.
The fruit, 4-1/2 inches (120 mm) long from stalk to tip, was picked up off the pavement on Howletts Road, which is overhung by the large and free-flowering Southern magnolia in the back garden of a house on Holmdene Avenue. In its original form, this cone-like fruit - called an 'aggregate of follicles' - would have been growing in the centre of the enormous, long-lasting, creamy-white flowers of the grandiflora, which can reach 12 inches (30 cm) across.
When it comes to pollination, the magnolia relies on beetles and sometimes flies to do the work. Bees evolved at a later date than magnolias, so they're not an option. Once pollinated, the petals fall and bright red seeds develop in the cavities in the surface of this structure. And when the seeds in turn drop in autumn they leave the cavities empty, as you see in the photo. There's a great series of pictures of the life cycle of the fruit on this website.
It's worth mentioning that there's only one other genus of trees in the magnolia family (Magnoliaceae): the equally ancient and remarkable tulip trees (Liriodendron).
Spring flowers
Maple flowers are easily overlooked in springtime, when there are so many exceptional blossoms to admire. They're mostly very small, green or yellow and relatively insignificant. The Norway maple (Acer platanoides) does make an effort, though you need binoculars or a telephoto lens to see them up close. Here are some pretty little bouquets high in the boughs of the Norway maple near the top of Danecroft Road:
On the left below, something else you might not recognise as a flower: a male catkin on a silver birch in Ardbeg Road, just opposite Onaway. Birches are monoecious, meaning they bear male and female flowers on the same tree. The males are long, yellow-brown and pendulous, while the bright green female catkins are half the size and upright. The males release pollen, which is carried by the wind to pollinate the females.
The right-hand picture of apple blossom was taken in the young orchard inside Hillcrest estate at the top of Sunray Avenue. There are four apple trees and four pears, planted just over two years ago on the sloping lawn between blocks 16-30 and 31-45. We had some concerns about these dwarf trees in their formative years as a few were slow to establish. Thankfully they've all bloomed this year, but they're not entirely in the clear yet. If there's anyone living nearby who can help with watering do let us know. There's a water tank very close to the trees so you won't have to carry water long distances.
Finally, we couldn't resist just one picture of a Yoshino cherry in magnificent full bloom at the end of March. This one is an older tree on the odd-numbered side of Stradella, just a little way along from Pedder estate agents.
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