The Complicated Whitebeam

The flowers on the whitebeam tree

Dear Readers, as the whitebeam (Sorbus aria) tree in my garden is having such a good year, I decided that I’d find out a bit more about it. These are not showy trees, but they have a subtle beauty – the leaves have tiny hairs on the underside which cause them to  flash white in the breeze, hence the name. When the leaves are in bud, they resemble magnolia flowers, and the flowers themselves are exquisite, and very attractive to insects. One reason for this is that whitebeam is a native, and has hence developed a whole range of associations with invertebrates  – the rather delightfully-named red midget moth (Phyllonorycter corylifoliella) mines its leaves, bees feed from the flowers, and birds will eat the berries (which are known as chess-apples in the north of England and, like medlars, are best eaten when nearly rotten). For a detailed recipe on how to make whitebeam jelly, click here.

Photo One by By Stainton - http://ia600504.us.archive.org/9/items/naturalhistoryof02stairich/naturalhistoryof02stairich.pdf, Public Domain, https://commons.wikimedia.org/w/index.php?curid=16801827

Red midget moth (Phyllonorycter corylifoliella) (Photo One)

Photo Two by Photo © Albert Bridge (cc-by-sa/2.0)

Chess-apples (Whitebeam berries (Photo Two)

The whitebeam is sometimes planted as a street tree, and has a rather pleasing domed habit, which makes it look a little like the trees that I used to draw when I was about six. They also have a tendency to twist and follow the sun, which can lead to some interesting effects.

Whitebeam as a street tree on Woodside Avenue, Muswell Hill.

A typical twisted whitebeam trunk

Whitebeam (Sorbus aria) in the Whitehall Estate, Archway, North London

Whitebeams are members of the mighty rose (Rosaceae) family, and are closely related to the rowans and wild service trees. Indeed, they interbreed with both of these relatives, and there are  a whole series of microspecies, which may grow only in one rocky crag or tiny local area, and nowhere else in the world. In Flora Britannica, Richard Mabey lists some of them:

The Arran whitebeam (Sorbus arranensis) grows only on steep streambanks on the Isle of Arran. This is a protected species, and only 283 specimens survived back in 1983.

Arran whitebeam (Sorbus arranensis) (Public Domain)

The least whitebeam (Sorbus minima) grows in a few sites in Breconshire, Wales. At last count there were 730 specimens. In 1947 the tree was endangered by mortar practice, and the MP for the area was able to persuade the army to stop shelling, and is credited with saving the tree from extinction. The main danger now is quarrying, which reduces the available habitat for the plant. All sites are now protected, and there are some least whitebeam trees in the Botanical Garden of Wales.

Photo Three by By Salicyna - Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=48413874

Least whitebeam (Sorbus minima) (Photo Three)

Wilmott’s whitebeam (Sorbus wilmottiana) grows only in woodland and scrub in the Avon Gorge, is on the IUCN Red List of Endangered Species, and has less than 100 individual trees left.

Photo Four copyright Dr Tim Rich, from https://www.iucnredlist.org/species/34732/80736838

Wilmott’s Whitebeam (Sorbus wilmottiana) (Photo Four)

There are only 22 individual Cheddar Whitebeams (Sorbus cheddariensis). As you might expect from the name, they live only in the Cheddar Gorge in Somerset.

Photo Five copyright Libby Houston from https://www.iucnredlist.org/species/79748432/79748436

Cheddar Whitebeam (Sorbus cheddarensis) (Photo Five)

But maybe saddest of all is the Ship Rock Whitebeam (Sorbus parviloba) which is known from only one specimen on the Herefordshire/Gloucestershire border. No wonder the IUCN describe it as ‘critically endangered).

Photo Six by Dr Tim Rich from https://www.iucnredlist.org/species/79749327/79749331

Ship Rock whitebeam (Sorbus parviloba) (Photo Six)

In general the flora of the UK is much sparser than that of mainland Europe, largely due to our fairly recent Ice Ages, which scoured much of the land clear of flowering plants (though we are a hotspot for mosses and lichens). And yet, we have this incredible diversity of whitebeams – I have only described a small selection of the endemic species above. Just to reiterate, these plants are found nowhere else in the world. Each of these trees is subtly different from the others in terms of growth habit, berry colour and leaf shape, and each one no doubt plays a part in its local environment. Who knew we were home to such riches?

It does make me wonder how my whitebeam ended up in the garden. Traditionally, whitebeams are associated with chalk – in his new book ‘London is a Forest‘ (which I heartily recommend by the way), Paul Wood suggests that ‘it’s almost as if it imbibes so much of the stuff that it seeps out through its leaves’. Whitebeams of all kinds are rare in the wild, especially on clay, and live for 100-200 years. Is it impossible that this tree was planted when the house was built back in 1897? It certainly looks like a tree in its prime to me.

Following on from my musings about what would happen to the garden when I eventually leave, I am almost tempted to apply for a Tree Preservation Order. Trouble is that it would cause all kinds of bureaucratic wrangles if I needed to prune it. Does anyone have experience of this? Do let me know the pros and cons. I’m not planning on going anywhere for a long time, but as we know, humans make plans and God chuckles….

White lilac, hawthorn and whitebeam

I have been looking for myths and legends surrounding the whitebeam, and here is a cracker from the Plant Lore website which I suspect might have been made up on the spot by someone’s Dad (much as I told my little brother that a monster would come out of the Belisha Beacon by the zebra crossing and eat him if he didn’t behave himself).

‘Two old ladies told me that their father permitted them to eat the young leaves of whitebeam. These had an almond-like flavour. However, they were permitted to eat only seven at a time as the leaves contained traces of a deadly poison’.

Interestingly enough, the seeds are said to contain Hydrogen cyanide, so maybe Dad was on to something, or was at least being cautious. I might have to pluck up the courage to have a nibble, though the leaves are surprisingly high up and I fear some clambering might be involved.

And while we’re on the subject of ‘folklore’, I couldn’t leave without mentioning the No Parking Whitebeam (Sorbus admonitor).

Photo Seven copyright Dr Tim Rich from https://www.iucnredlist.org/species/79740183/79740280

A No Parking Whitebeam (Sorbus admonitor) (Photo Seven)

The first example of this species to come to the attention of botanists was discovered in a lay-by at Watersmeet in North Devon in the 1930’s, with a ‘no-parking’ sign tacked to the bark. E.F Warburg, an eminent plant scientist, knew that it was different from the other local microspecies, the Devon Whitebeam, but it wasn’t until the tree’s DNA was studied in 2009 that it was given species status, and the Latin name ‘admonitor‘ (meaning ‘to tell off’). There are about 100 of these trees, which as we’ve seen almost counts as a healthy population in the world of whitebeams. Let’s hope that its interesting name keeps it in the public eye.

Incidentally, the species name of ‘our’ whitebeam, ‘aria‘, comes from the Latin name ‘aries’, meaning prop or battering ram. The wood is very hard, and was used for axles and shafts until superseded by cast iron. The diarist John Evelyn admired the wood, and used it to panel one of his rooms, and it was also used to make gunstocks.

Photo Eight by By Gaffer206 - Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=11411627

Cross-section of a whitebeam trunk (Photo Nine)

And, as usual, a poem.  Paul Farley is a poet of the edgelands, and I think he captures the shapeshifter nature of the whitebeam: one of only 33 native trees in the UK, but with a myriad of forms, a plant of parks and gardens but also one found hiding in surprising places. The whitebeam is a tree that invites us to wonder what would be possible if we appreciated what we have.

Whitebeam

The sixty-miles-per-hour plants, the growth
that lines the summer corridors of sight
along our major roads, the overlooked
backdrop to Preston 37 miles.
Speed camera foliage; the white flowers
of Mays and Junes, the scarlet fruits of autumn
lay wasted in the getting from A to B.
Hymn to forward-thinking and planting schemes,
though some seem in two minds: the greenwood leaves
are white-furred, have a downy underside
as if the heartwood knew in its heart of hearts
the days among beech and oak would lead to these
single file times, these hard postings
and civilised itself with handkerchiefs.

Paul Farley (2003)

Photo Credits

Photo One by By Stainton – http://ia600504.us.archive.org/9/items/naturalhistoryof02stairich/naturalhistoryof02stairich.pdf, Public Domain, https://commons.wikimedia.org/w/index.php?curid=16801827

Photo Two by © Albert Bridge (cc-by-sa/2.0) from https://www.geograph.ie/photo/4152435

Photo Three by By Salicyna – Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=48413874

Photo Four copyright Dr Tim Rich, from https://www.iucnredlist.org/species/34732/80736838

Photo Five copyright Libby Houston from https://www.iucnredlist.org/species/79748432/79748436

Photo Six by Dr Tim Rich from https://www.iucnredlist.org/species/79749327/79749331

Photo Seven copyright Dr Tim Rich from https://www.iucnredlist.org/species/79740183/79740280

Photo Eight by By Gaffer206 – Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=11411627

12 thoughts on “The Complicated Whitebeam

  1. Brian Steedman

    Peter Marren has a lot of interesting things to say on Whitebeams in his recent book ‘Chasing the Ghost’. Basically Sorbus frequently throws up new variants and thus new rarities. It always seems to succeed in being beautiful and interesting!

    Reply
  2. Neo

    Interesting read, wish more of these trees were planted along streets as they seems to have everything.
    Love your posts, keep up the good work 🙂

    Reply
  3. tonytomeo

    It is interesting that whitebeams are grown in landscapes there. They are unheard of here. There are species that are native to North America, but none are native here, and none can be found in nurseries. Two years ago, I got a pair of mountain ash, which is the same genus, and native to Eastern North America. I purchased them online, just because that is the only way to obtain them.

    Reply
    1. Bug Woman Post author

      I wonder if their fondness for chalk has anything to do with their rarity in North America? Interesting…..they are obviously adaptable, as my tree is growing in heavy London clay.

      Reply
      1. tonytomeo

        That would make sense. Even the North American species of Sorbus seem to be discriminating about where they live. They are happy in their native range, but are rare outside of it.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.