Street Trees

Introducing Hippophae salicifolia – the willow-leaved sandthorn

Our mystery South London street tree has been identified thanks to a correspondent who was able to recognise a fine avenue of Hippophae salicifolia. Several others suggested sea buckthorn (Hippophae rhamnoides) which, as it turns out, was close but discounted due to size (tree rather than a bush), evergreen foliage and few berries. My own guess at a food plant of giraffes was wide of the mark…

Hippophae salicifolia, street tree, London
Word on the Street: Hippophae salicifolia street tree on Curlew Street, London

The positive identification was verified by the Hippophae salicifolia page on Hillier Nurseries’ website featuring a picture of the exact same street tree I had been struggling to identify, apparently there is a 15m specimen to be found at Kew too.

The common moniker that has emerged for this tree is the very unsatisfactory ‘willow-leaved sea buckthorn’. This plant’s natural habitat is dry Himalayan river valleys hundreds of miles from the sea, so I detect botanical imperialism at work in a name relating to our familiar European coastal species more appropriately known as sea buckthorn.

In my opinion our tree needs a new name – Hippophae are sometimes called sandthorn or sallowthorn; our tree is certainly not sallow, so I am proposing willow-leaved sandthorn.

Any takers?

Other Willow-leaved sandthorn (Hippophae salicifolia) resources:

Hippophae salicifolia on the Plants For a Future website
Salicifolia is listed on the Hippophae Wikipedia entry, but there is no separate species page yet.
My willow-leaved sandthorn Flickr set

Street Trees

Stumped: unidentified street tree

Leaves and orange berry on the mystery street tree
Southwark Leaf and Berry Combo: what is this thorny, evergreen tree with orange berries?

On Curlew Street, in that late eighties enclave of converted spice warehouses just east of Tower Bridge on the south bank of the Thames, I have noticed a curious tree.

Planted, I imagine, when the area was being cleaned up, they look to me like Giraffe fodder: tall trees with long branches, each bearing a sparse canopy of thin, evergreen leaves and the occasional orange capsule of a berry. It would take a long-necked animal with a dextrous tongue to negotiate these thorny branches – not many of them in these parts. And could a tree from the dry plains of sub Saharan Africa thrive in this urban corner Europe?

So what can they be? I have a hunch that the enthusiastic developers of this former dockland took its spicy heritage to heart, and planted rare and exotic street trees to complement the cinnamon, cardamom, ginger and cloves referenced in the new apartment block names. If so it is a reference lost on this flummoxed amateur plant identifier. Or perhaps they are another illustration of Southwark council’s experimental street tree planting programme, as explored in recent posts about Strawberry Trees and the unlikely Persian Silk Tree, to be found in nearby streets.

unidentified street tree, Curlew Street
Evergreen: Mystery trees in Curlew Street

My mystery trees appear to be thriving in this narrow, enclosed street and while I estimate they are up to 30 years old, they look youthful, as if many years growth lie ahead. Given their clear suitability to the urban environment, their elegance and exoticism, they are a species I have not come across before and one whose identity I am, well, stumped by.

I hope the photos in this post will help identification, here’s the Google street view too and you know where to find them if your interest is piqued:

Street Trees Urban landscape

Red Oak lives up to its name

In a post about the North American Red Oak (Quercus rubra) I wrote in the balmy days of August, I rather flippantly stated that ”… the beauty of this tree in its native New World is surely its fiery autumn colours which in our damper and milder oceanic climate is watered down from a rich red to a pedestrian caramel brown.”

Red Oak (Quercus rubra), More London
Confounded Tree: A Red Oak blatantly turning red

I have been perversely willing all the specimens of Red Oak in London (and I now realise there are a lot) to take on muddy shades in time for bonfire night so I could fill screenloads of blog pixels with an ironic firework-themed, told-you-so posting about the unsuitability of this tree to adorn our streets and public spaces.

Red Oaks (Quercus rubra), More London
Leaf It Out: More Red Oaks making spectacles of themselves with striking leaf colours

Well, there is nothing like humility, so I feel compelled to admit that I have been wrong about Quercus rubra. The Red Oak has come into its own in the past week as the trees I originally wrote about in the More London development are starting to, well, delight. Some trees are deep red, others brick red, more are yellow and orange. What this species lacks in character during the rest of the year, it is now making up for.

That said, I did bump into this rather splendid Acer palmatum or Japanese Maple in Highgate’s Waterlow Park last weekend…

Acer palmatum
Red Alert: Nothing beats the colour of the amazing Acer palmatum or Japanese Maple . This one is in Waterlow Park in north London
Street Trees

Strawberry trees in Southwark

I was surprised and excited to bump into a row of newly planted Strawberry Trees (Arbutus unedo) in a Southwark street recently. As a child with an interest in native trees, I was fascinated to read about this mysterious tree with a compelling name in my botanical guidebooks. It was described as very rare and hanging on in Ireland where it had survived the last ice age.

Flowers and fruit of European Strawberry Tree (Arbutus unedo)
Cream of the crop: Fruits and flowers of the Strawberry Tree (Arbutus unedo) in south London

They line Melior Street, a short turning in the shadow of the looming Shard, that monument to megalomania that marks the redevelopment of London Bridge station.

Southwark appears to have an experimental approach to street tree planting which I admire: I have never seen the Strawberry Tree planted in London streets before (although this species and other Arbutes are a common feature of San Francisco sidewalks). Earlier in the year I came across a Persian Silk Tree (Albizia julibrissin) in the same borough, and I am now on the lookout for more unlikely foliage that may be lurking in the neighbourhood.

While the Persian Silk Tree is an exotic import with undeniably alien looks, the Strawberry Tree is a native of more familiar landscapes. It is found in the western Mediterranean and the Atlantic fringe from Portugal to, famously, south west Ireland where it is common in parts of County Kerry. It may hail from less far afield, but it was never a component of the post-glacial Bermondsey forest and consequently the Strawberry Tree’s evergreen foliage and drupe-like berries provide unexpected lushness to its adoptive environment.

Characterised by bushy growth in the wild, Southwark’s trees have been trained or grafted to produce 2 metres of straight trunk before this characteristic is allowed free rein. The English name arises from the appearance of the round pitted fruits, but they are actually part of the Ericaceae family and therefore related to the heaths which becomes apparent in the white bell-shaped flowers. A lovely feature of this Arbutus is the simultaneous flowering and fruiting in the autumn, the fruits take twelve months to ripen and go through every conceivable shade between lime green and vermillion. At this time of year, the trees sport a jaunty array of ripe red fruits interspersed with citrus coloured baubles and bunches of white flowers. Gorgeous.

Strawberry tree (Arbutus unedo) street tree, Bermondsey
Strawberry Daquiri: Arbutus unedo guides the thirsty into the Horseshoe Inn

Here’s the view down Melior Street from Google streetview showing the newly planted Strawberry trees:

Further reading:

Map of native and non-native records for Arbutus unedo in Britain and Ireland on the Biological Records Centre website
Description of the magnificent and elderly Strawberry Tree in Waterlow Park, Highgate
Wikipedia entry for Killarney National Park where native Irish Arbutus unedo is found (needs some editing!)
My Flickr photoset including Arbutus unedo

Street Trees

Persian Silk in Globe Street

I was transfixed by the charms of a Persian Silk Tree (Albizia julibrissin) in Southwark today. A most majestic and unusual (for England) street tree, in fact a rarely-planted tree anywhere in the UK, street or otherwise. This is perhaps a cautious test planting to see what happens – the tree has a reputation for invasive behaviour in the US and Japan according to the trusty wikipedia entry

Persian Silk Tree (Albizia julibrissin)
Persian Silk Tree (Albizia julibrissin) in Globe Street, SE1

On first impressions Albizia julibrissin has a lot going for it – very attarctive and exotic foliage, a long flowering period and a lovely spreading habit, but I’m sure our forbears said the same about the Tree of Heaven.

Persian Silk Tree Albizia julibrissin foliage
Persian Silk Tree foliage and (look closely) flowers

It seems appropriate to plant this tree in Globe Street, an otherwise nondescript turning off Great Dover Street, but clearly a road with ambition. From a distance the tree’s profile screamed for attention and I couldn’t resist a closer look which was rewarded with the mimosa-like elegance of the foliage and jaunty flowers that are all stamen and no petal – there were a lot but they may not be visible in my pictures. The unexpectedness of this tree was compounded by the planted bed that surrounded it. A nice bit of Guerilla Gardening, an activity to be encouraged I believe – people claiming a stake in their streets and beautifying derelict land. It’s great to see the usually small-scale and unconstrained planting, not always appropriate but an antedote to the often institutional planting of local authorities. Unfettered middle class anarchy!

Looking down Globe Street from Great Dover Street:

Street Trees

A Tree Grows in Bermondsey

The Tree of Heaven (Ailanthus altissima) is a common tree of street plantings, parks and gardens, in fact it pops up everywhere. It has a curious habit (in London at least) of blending in, it has a passing resemblence to the Ash (Fraxinus excelsior) or the Walnut (Juglans regia) and seems inoffensive when it first appears. It is in fact a vigourous tree, growing rapidly into an attractive small tree and then a shady large tree. It often looks planted but in fact it may very probably have arrived under it’s own steam.

Ailanthus altissima - Tree of Heaven
Ailanthus altissima - A Tree of Heaven blending in on an estate wall in Bermondsey

Whenever I spot one of these colonisers of uncared-for plots of land it isn’t long before the parent tree becomes apparent, typically a mature planted specimen within 100 metres of a not-so-obviously planted specimen. Because of it’s rapid grown and it’s ability to push out suckers almost at will even through tarmac or cracks in walls, a patch of waste ground can resemble a possibly-planted mini ToH arboretum within two or three years. By the time someone notices and decides to cut down the encroaching spinney, these offenders will be ready to send forth sucker reinforcements and so the cycle continues.

Often the ToH will appear to be a bush as the one in this picture does, don’t let this simulacrum of pruning fool you though – chances are it will be the multi-stemmed regrowth of a casually hacked mono-trunked invader.

Beyond these shores the Tree of Heaven, or Ghetto Palm, has gained notoriety for it’s invading habits and is regarded as out of control and an unwanted alien in parts of Europe and America. It’s ability to grow anywhere has also been celebrated in literature and my post title references Betty Smith’s 1943 novel ‘A Tree Grows in Brooklyn‘ which uses the Tree of Heaven as a metaphor for the tenacity of her inner city dwelling characters.

Check out the likely parent tree just next to the pub: