After an unpredictable May the hot weather finally arrived in mid-June. This is a dangerous time of year for our youngest trees, especially the ones that have been planted in the last couple of months. The planting season should have ended on March 31 but for the second year in a row it’s overrun by a long way, exposing small trees to challenging conditions.
For the saplings to grow deep roots now it’s going to take a lot of water, so please make sure you look out for signs of stress - basically leaves that are limp and appear as if they might be drying out. We’re aiming for ‘turgid’ leaves and shoots: bright, firm and plump, not ‘flaccid’, dull and drooping. As always, there’s watering guidance on the website.
Also do keep an eye on the wooden stakes supporting the new trees. Some of the council’s maintenance contractors write the date on the stake every time they water, so you can judge if the green bag has just been filled. They’re now supposed to fill the bags with 50 litres every week during June, July and August for the first three years after planting, but during long, hot, dry spells the trees will definitely need more. In April and May their watering schedule for years 1 and 2 is once a fortnight.
If the weather’s wet, bear in mind that rainfall doesn’t do newly planted street trees much good, although it might have some benefit if they’re planted in grass.
This year’s tree tally
By the middle of June the total number of trees planted since the season began in November reached 44, compared to the previous year’s 53. There are full details here but the headline numbers are:
Carver Road (2)
Casino Avenue (2)
Delawyk Crescent (1)
Elfindale Road (7)
Elmwood Road (2)
Frankfurt Road (1)
Half Moon Lane (3)
Herne Hill (5)
Holmdene Avenue (2)
Red Post Hill (3)
Sunray Avenue (5)
Winterbrook Road (10)
Wyneham Road (1).
Overdue trees
Seven other trees on Southwark’s schedule for 2021/22 still haven’t gone into the ground and it seems unlikely that they’ll now be planted so late in the day. They’re made up of:
Two in Delawyk (a lime on the perimeter road and a fruit tree in the middle of the estate)
One on Elmwood (a replacement for the dead birch that was removed last August from near the junction with Wyneham)
One in the grounds of Pynnersmead flats, towards the bottom of Herne Hill (a Scots pine, or Pinus sylvestris) that had originally been ordered for Delawyk
Three on Sunray, the big grassy space opposite the junction with Casino (a replacement for an ash that stood between the English oak and a young cherry at the front, and two fruit trees for the area towards the back).
The Sunray fruit trees were originally timetabled for 2020/21 so if they’re finally planted this coming winter they’ll be a full two years overdue.
Plans for 2022/23
Paul and Jeff, our co-organisers, had two long and very productive walkabouts recently with Ernst Erasmus, the council tree officer for this area. Ernst was scoping out the locations we’d proposed for our big planting programme in stretches of Herne Hill roads that haven’t previously had any trees at all. The project, which has been delayed by a year until the forthcoming season, will be funded from the awards we’ve received from Southwark’s Cleaner Greener Safer scheme.
We achieved a lot, confirming most of our suggested sites and agreeing suitable species. We’ve already discussed the majority of these locations with our street leaders, although there will be some new ones where Ernst has gained the agreement of the residents. Our provisional plan for 2022/23 is now posted, so please do have a look in case there are any problems for your street.
Ernst will have to order the trees soon, so we’d ideally need to hear from you by the end of June as supplies from nurseries are likely to be tight.
There are 60 trees on the list, including 45 marked ‘CGS’ that we’ll fund if our resources stretch that far. The others have been organised separately by Ernst or are replacements for past losses, including two trees being provided by Lambeth.
Summer blossom and fruit
The horse chestnuts have given us a lot of pleasure over the past couple of months, helped by the fact that the three species planted in Herne Hill bloom at different times. First come the common horse chestnuts (Aesculus hippocastanum), the ones that produce the classic conkers. There are big ones on Red Post Hill, in Sunray Gardens and at the front of the Delawyk estate, and also two smaller specimens in the lower cul-de-sac on Casino Avenue. Their big white panicles, or clusters of flowers, open in late April.
Next, in May, come the red horse chestnuts (Aesculus x carnea), which have multiplied recently. We’ve now got them at 53-55 Casino, 18 Sunray, Carterscroft on Red Post Hill and Denesmead on Herne Hill.
Finally it’s the turn of the white-flowered Indian horse chestnuts (Aesculus indica) in June-July. There are three altogether in the Casino cul-de-sacs and another, pictured below, on Stradella Road. It’s the first tree on the left if you’re coming from Burbage Road, just before you get to no. 105, and it’s now getting big enough to put on a striking display.
For a splash of vivid colour, though, look into the branches of any big native wild cherry (Prunus avium). Up there, if the birds haven’t taken them all yet, you should see a good crop of tempting red cherries, like these opposite 9 Burbage Road.
There seems to have been a good harvest this year, and in early June you could find yellow, orange, bright red and almost black fruits - at different stages of ripening - in the same bunch at 96 Elfindale.
Commercially cultivated Prunus avium are known as sweet cherries in the fruit trade to distinguish them from sour cherries (Prunus cerasus) like the Morello.
Decoding the birches
You’ll find birch trees on almost every street in this area, easily recognised by their distinctive white bark. But what’s not immediately obvious is that our urban birch forest is made up of at least four different species, and unless you’re prepared to climb up and peer at the buds in winter you can only reliably tell them apart when the leaves are on the tree.
The bark alone isn’t a consistent identifier - the trunk and branches change colour as they get older and there’s a lot of variation even among the same species. Southwark plants nine types of birch altogether, so there might in fact be other types tucked in here and there. All the birches we’re looking at now can be found on Elfindale Road.
Silver birch
Let’s start with the silver birch (Betula pendula), the second most common street tree in Herne Hill after the London plane. It’s one of two birches native to Britain and it’s what’s known as a pioneer species, meaning that it’s usually the first tree to colonise bare or fire-damaged land and form woods. It’s also the easiest to recognise from its outline - tall, narrow and graceful, unless it’s been carelessly lopped. The twigs and branches of mature trees are pendulous (hence the Latin name) and, like all the birches, it casts a pleasant dappled shade.
The pictures below are of the relatively young silver birch at 76/78 Elfindale. The smooth bark is mostly white at this stage, although it will have started off as reddish-brown before often taking on a pinkish hue. The real giveaway, though, is the characteristic black diamonds formed near the base that confirm this is a silver birch. No other species has them. These diamonds will spread up the tree as it ages and the bark will become silvery-grey, cracked and craggy.
The diamond-shaped leaves, too, are unique. They’re widest near the stalk, with irregular-shaped teeth along the edges, and - if you’ve got the patience to count them - they always have six pairs of veins.
Downy birch
The downy birch (Betula pubescens), the other of our two natives, is much more common in the countryside of northern England, Scotland and Northern Ireland than the silver birch and much, much rarer in cities. As far as we can see there are only two downy birches on our streets: one at the top of Ruskin Walk - the second tree down from the postbox - and the one in these photos (below) at 26 Elfindale.
They’re less elegant and bushier in outline than the silver birch but the bark is more interesting: red-brown when young, but soon developing these lovely horizontal bands of pink, white, pale brown and orange. It also stays smoother and browner than the silver birch as it gets older.
The leaf stalks, shoots and the underside of the leaves bear the soft white hairs that give the tree its name and the leaf is much more rounded than the silver birch and widest in the middle. The teeth are more uniform, while the number of veins varies from five (like the Ruskin tree) to eight (the one on Elfindale).
What can make identification tricky is that the two native birches, silver and downy, easily hybridise, so their features often blur into each other.
Himalayan birch
The birch that’s been planted the most round here in the past 10 years or so is the Himalayan birch (Betula utilis jacquemontii), which as the name suggests originated in the western Himalayas. This is the one with gleaming white bark that tends to peel in the crown of the tree. It has thick, dark foliage and a much rounder, wider profile than the silver birch.
The leaf always has between seven and nine pairs of veins - seven in the case of this tree at 81-83 Elfindale.
Erman’s birch
Finally, the newest birch in the neighbourhood: the Erman’s birch (Betula ermanii), planted last month at the very top of Elfindale, to the side of H & M Lounge at 77 Herne Hill. The Erman’s, a native of northeast Asia and Japan, will grow into a neat, conical tree with cream-coloured, pink-tinged bark, but this youngster has a remarkable caramel-coloured trunk.
The heart-shaped leaves taper to a point and have 6-11 veins. They’re the largest leaves of any of the four species we’ve looked at, ahead of the Himalayan, the downy and lastly the silver birch.
Birches and allergies
Not everyone loves birch trees, though - especially not hay fever sufferers. The charity Allergy UK says birch pollen is ‘one of the most potent allergens, triggering not only allergic rhinitis and allergic conjunctivitis symptoms, but also pollen food syndrome - allergies to certain plant-based foods’. Herne Hill Tree Watch doesn’t recommend planting any new birch trees in the neighbourhood, especially since we already have a plentiful supply and should be focusing on diversity as the climate heats up.
There have been only two birches planted here this season. The first, in April, was a silver birch opposite the flats at 76-86 Elmwood Road that we misidentified in that month’s newsletter as a downy birch. It was the pale brown bark that threw us.
The second, early in May, was also a silver birch but an unusual purple-leafed version (Betula pendula 'Purpurea') at 44 Frankfurt Road. It's so tall and spindly that it was drooping perilously into the road until we reported it to the contractors, who stuck in a long bamboo pole to support it.
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