Leylandii: planting menace in the mind

Cypress Leylandii (centre), Mill Lane, Bridge. Given space to grow, Leylandii is not unattractive in itself. Image © copyright 2016

Leylandii, that notorious, rapid-growing, evergreen, furry monster which has blighted suburban gardens and caused domestic disputes across the country for decades: we all recognise it and despise it, don’t we? Well things are not quite what they seem…

Members of the Cypress tree family(1) are generally recognised by their evergreen, fern-like branches. Cypress Leylandii is a man-made hybrid within that family. It was created in Britain in about 1888 by arboriculturists who were sharing conifer seeds imported from America. It is not clear who actually produced the first tree of this particular hybrid but a certain Mr Leyland got the credit, or should we say blame? Leylandii is fast growing and can grow to 50ft in 15 years or so, and it will grow to 150 feet if left unpruned. It was created by crossing two North American trees, the Nootka Cypress from Alaska, which provides great hardiness, and the Monterey Cypress from California, which gives it rapid growth. In their natural setting, both of these trees are really quite beautiful and they would never have cross-pollinated naturally.

Leylandii became popular in modern British gardens when it was discovered that, planted in a close row, they quickly provide an effective tall screen to give privacy. However, pruned closely such hedging can appear overly severe, yet if not controlled at all, the trees rapidly outgrow their setting and become a nuisance.

Bridge Tennis Club. Strictly controlled conifer hedging can look overly severe, and hard pruning leaves ugly bare patches which may never recover. Image © copyright 2016

Yet, surprisingly, people who complain about Leylandii in their neighbours’ gardens may not actually be seeing Leylandii at all, they may be looking at another similar tree in the Cypress family, the Lawson Cypress. Sometimes called a False Cypress, this tree is in fact a cedar, known in America as the Port Orford Cedar because it comes from that region of Oregon. It was introduced to Britain in the 1850s by the Lawson nursery in Edinburgh. It is often planted for hedging for similar reasons to Leylandii. Its flowers can make it a more attractive tree, but if left untended, it causes the same problems.

Male (red) and female (brown) flowers on this Lawson Cypress on Patrixbourne Road can make it an attractive tree in spring. Image © copyright 2016

However, this is not yet the full story: another group of similar looking trees in the Cypress family, also commonly used for tall hedging in Britain, are the Thujas. These are again cedars, notably the Western Red Cedar and the White Cedar from the Pacific coast of North America. While all these different possibilities make identification complex enough, the situation is further complicated by the fact that over the years all these trees have been further crossed and selectively bred to create size, growth habit and colour variations which range into the hundreds.

The distinctive cone of a Thuja growing in Bekesbourne churchyard. Image © Copyright 2017.

In all the furore over Leylandii’s role in irresponsible hedge planting, conifers in general have gained a bad reputation which they do not really deserve. The original trees that created some of the most notorious hybrids were all selected because they were and are hansom trees in their own right. In the correct setting they make wonderful specimen trees and their wood is highly valued by craftsmen across the globe: the timber of Port Orford Cedar is used in America and Japan for making arrows and musical instruments; Thuja wood is very decorative, so it is often made into ornamental bowls and boxes; Nootka Cypress is considered one of the most useful timbers in the world, it is very resistant to rot and is often specified for the construction of wood cabins, decking and traditional small boats.

What a shame it is that, simply because of unsuitable placement in modern suburban British gardens, many conifers have been tarred by one common villainous appellation ‘Leylandii’, a name which arouses such contempt amongst the British public.

(1) In arboricultural circles there has been and remains a great deal of debate about which trees actually belong in the Cypress family and which should be placed into other groups. For the sake of simplicity here we have tried to cite commonly accepted classifications.

The acorns of the oak

An oak acorn showing the aril in the cupule, then split to reveal the nutty kernel. Image © copyright 2016.

An oak acorn showing the aril in the cupule, then split to reveal the nutty kernel. Image © copyright 2016.

The acorn is very recognisable as one of Britain’s woodland nuts: it grows in all three of our most common oak trees, the English Oak, the Sessile Oak and the evergreen Holm Oak, where it sits on the branch like a little boiled egg in a tiny egg cup. However, what we see on the tree is just the outer shell called the ‘aril’ attached to its woody ‘cupule’: once it has fallen from the tree in Autumn, the aril will split open revealing the nut kernel inside.

Acorns are nutritious and in some of humanity’s older cultures, notably in Southern Europe and parts of the Americas, they formed part of the main Autumn diet, but this practice does not seem to have been prominent in Britain, quite possibly because the acorns of our native English Oak contain very high levels of tannin which need to be thoroughly soaked out before they are palatable to humans. This same chemical makes some of our acorns poisonous to cattle and horses, and may cause serious illness in humans, so we strongly urge readers not to try eating them.

However, in oak woods (like the New Forest) where deer are resident, acorns provide a valuable food source for the deer, which appear immune to any harmful effects, and in many parts of our countryside oak acorns are also an important cold season food for birds including jays and woodpeckers and mammals such as squirrels, mice and other rodents. Pigs love acorns too and in olden times it was traditional for swineherds to allow them to roam loose in oak woodland in Autumn so that they could fatten up for winter.

A jay plucking acorns from the oak tree on the junction of Mill lane and Western Avenue, Bridge. Image © copyright 2016.

A jay plucking acorns from the oak tree on the junction of Mill lane and Western Avenue, Bridge. Image © copyright 2016.

Jays, like squirrels, will bury acorns in various locations around their homes and come back for them when they are hungry, if they can remember where they are. Recent studies have shown that the role of jays in the valuable work of propagating our native oak trees has been hugely underestimated and we now know that each Jay may bury thousands of acorns. Not all the acorns are retrieved and this may not always be as a result of the birds forgetting where they were buried, it may be that some jays do not survive long enough through a severe winter to eat all the nuts they cached, or it may be that more were stored than needed: either way, we have jays and squirrels to thank for many of the oak trees we see in our countryside today.

Jays may be observed this week picking acorns in the Holm Oaks near Green Court, Bridge and in the small Oak tree on Mill Lane (pictured above).

Notes on a hard tree

A Hornbeam samara. September. Whitehill Wood. Image © copyright 2016.

A Hornbeam samara. September. Whitehill Wood. Image © copyright 2016.

At this time of year, those who gaze up into the trees while walking in our local woodland may notice certain pendulous growths hanging like little lanterns from the branches on some of the trees. These are the ‘samaras’ of the Hornbeam tree, the winged seed cases that fall from the tree and spin in the wind to plant themselves elsewhere.

The Hornbeam is an important native tree of southern Britain and much of Europe and Asia. It’s name literally means ‘hard tree’, ‘horn’ being an old term for hard, and ‘beam’ the old English word for tree, which relates to the German ‘baum’ still in use today. In Autumn the distinctive samaras make it an easy tree to recognise, but for much of the year the Hornbeam tends to be confused with the beech because the leaves are of similar shape and size.

The Hornbeam and beech leaves compared. Image © copyright 2016.

Hornbeam and beech leaves compared. Image © copyright 2016.

However, there are some easy ways to distinguish them: beech leaves have a smooth but slightly wavy edge, while the rim of the Hornbeam leaf is toothed like a saw, in fact double-toothed so there are big serrations round the leaf with smaller ones set within them. The bark of the beech is also smooth with a rather plain greyish colour, while the Hornbeam has a very distinctive threading pattern running up it. These threads will become pronounced ridges and troughs in the bark as the tree matures.

The weaving patterns in Hornbeam bark become ridges and troughs in mature trees. Image © copyright 2016.

The weaving patterns in Hornbeam bark become ridges and troughs in mature trees. Image © copyright 2016.

As the name tells us, the wood of the Hornbeam is very hard, in fact it is just too tough for most general carpentry work, but it is very useful where a hard-wearing material is required. Traditionally it was the wood of choice for making the yokes which lay across the shoulders of oxen for ploughing, and it was also used to make coach wheels, tool handles and the cogs and other working parts of our historic English windmills and watermills.

Today the timber is less used, but another feature of the Hornbeam, which it does share with the beech, makes them both valuable trees in our modern local landscape. Many of Kent’s old fruit and hop fields were bordered with Hornbeam and beech hedges (particularly noticeable in the Selling area today) and, although they are not evergreens, hedges formed with these trees hold on to their leaves right through the year, thereby providing winter shelter for all kinds of birds and other wildlife.


The Kentish Apricot

Apricots growing in the Bridge area, July 2016. Image © copyright 2016.

Apricots growing in the Bridge area, July 2016. Image © copyright 2016.

This month thousands of Apricots have been ripening on trees in the Bridge area. That may come as a surprise to many people but, ironically, even more so to those who are most knowledgeable about fruit growing, because for centuries it has been considered virtually impossible to grow Apricots commercially in Britain. A few gardeners have managed to grow them as a novelty in special conditions, but generally our summers were considered too wet, our winters too variable and our spring frosts too unpredictable for growing these demanding fruits on a large scale. The trees flower very early in spring, so the risk of just one late frost destroying an entire crop was too high for Apricots to be a viable option for British fruit growers.

However, in recent years all this has changed as new cultivars have been developed specially to suit the British climate. Today Apricots are grown in abundance on various farms across Kent, including one within Bridge parish. Apricots plucked fresh from the tree provide a delicious and entirely different taste experience from the bland supermarket imports we British are used to, and our new home grown varieties are now considered amongst the tastiest to be found anywhere. Additionally they are rich in vitamins A and C together with potassium, copper and fibre. Surprisingly, Apricot kernels are often used on the continent to supplement almond flavouring, typically in Amaretti biscuits and the well known liqueur Amaretto.

Tradition has it that the Apricot comes from Armenia, a small country to the East of Turkey (the Apricot’s Latin name Prunus Armeniaca actually means ‘Armenian Plum’), but historians dispute this, arguing that evidence shows the fruit has been in cultivation in China, India and Persia since ancient times.

An Apricot tree laden with fruit is a beautiful thing to see in its own right and it is a delight to have these new exotic immigrants in our traditional fruit growing landscape, but they are still a relatively rare and valuable crop, so we do not disclose their location. Those who may think to go in search of them should be advised that they fruit early and this year’s harvest has already been picked.

In Blackthorn Winter

Blackthorn blossom, the Butts, Bridge. Image © copyright 2016

Blackthorn blossom, The Butts, Bridge. Image © copyright 2016

The Blackthorn is a small shrubby tree common to the English hedgerow. During winter it appears little more than a rather nondescript dark prickly bush but, in the spring, hordes of white flowers arrive like snowfall upon the thorny boughs. Later in the year these will develop into the small, sour tasting, blue-black fruits we know as sloes.

In folklore the Blackthorn tree is considered a sinister tree associated with winter, witchcraft and warfare. It can be a sign of ill omen, yet if used correctly it may offer protection against evil too and it was planted to create boundaries both in a practical sense, with prickly hedges to deter intruders, and in a spiritual sense, to protect against evil spirits. Witches carried walking sticks made from its branches and the traditional Irish cudgel (bata), more commonly know as a shillelagh, is made of a Blackthorn trunk and its heavy club-like root. Some authorities state that the term ‘black rod’ originally derived from a shaft of Blackthorn fitted with horns for use as a weapon, and we suggest it may therefore be no coincidence that the role of the Usher of the Black Rod in British parliament is to keep order and maintain security.

In the sunny days of April and May the Blackthorn’s flowers shine out prettily and pristine against an azure sky. Yet, as recent days in our little corner of Kent have shown, the weather in early spring can be very cold, and in such conditions the blossom may truly be reminiscent of snow lying on the hedgerows. Referring to the cold spring weather of his own district in his famous book ‘The Natural History of Selborne’, Gilbert White tells us “The harsh rugged weather obtaining at this season, is called by the country people ‘Blackthorn Winter'”.

The crimson curls of Poplar

Devil's Finger. The catkin of a Hybrid Black Poplar. Bridge area. Image copyright © 2016

Devil’s Finger. The catkin of a Hybrid Black Poplar. Bridge area. Image copyright © 2016

Walking out along the footpath between Sheep Dip Lane and the Butts after strong winds we find a scattering of crimson catkins and the half-formed curls of immature fallers too. These are the male catkins of one variation of our native Black Poplar tree. In folklore the mysterious, exotic catkins were called ‘Devil’s fingers’, and it was considered bad luck to pick them up from the ground.

Today the Black Poplar is not very well known but it is a characterful deciduous tree growing up to 30m in height. The bark is greyish, roughly ridged with frequent burrs. The leaves are heart-shaped, dark green and shiny.

Hybride Black Poplar Catkins, Bridge area. Image copyright © 2016

Hybride Black Poplar catkins, Bridge area. Image copyright © 2016

True wild Black Poplars are now very rare, so rare in fact that they are considered our most endangered native tree because, being so scarce in the countryside, they are seldom pollinated by other trees of the same wild species. They are almost always found near water and were in fact formerly called Water Poplars for this reason. In John Constable’s day (1776-1837) they were a common feature of the river bank, as some of his paintings testify.

However, by the 1850s a new hybrid of our native wild Black Poplar and the American Eastern Cottonwood tree had been introduced for its faster growing properties and tolerance to more general growing conditions, and it was widely planted for both its scenic qualities and timber. This, being soft with bend and shock resistance, was used for making carts and clogs which took a regular battering on England’s old roads. In the years following, the wild trees were pollinated by the hybrids to such an extent that, after 150 years or so, hybrids dominate and very few true wild Black Poplars now remain.

Immature Hybrid Black Poplar catkins. Bridge area March 2016. Image copyright © 2016

Immature Hybrid Black Poplar catkins. Bridge area March 2016. Image copyright © 2016

Another variant which is commonly seen in the British countryside is the Lombardy Poplar, sometimes called an Italian Black Poplar, which is a very familiar tall, thin, elegant tree often planted in rows to provide wind shelter beside exposed stretches of farmland.

Identifying Poplars and their hybrids is notoriously difficult, especially before leaf formation, but having examined the catkin bearing trees near the footpath, we believe they are likely to be Hybrid Black Poplars.

Tree matters

On the positive side: tree planting in built areas like this one in Ford Close, Bridge, can help to prevent runoff and flooding. Image copyright © 2015.

On the positive side: tree planting in built areas like this one in Ford Close, Bridge, can help to prevent runoff and flooding. Image copyright © 2015.

This week received a letter from Steve Fawke, Bridge Parish Councilor and tree conservationist, bringing to our attention a set of statistics which appeared recently in The Guardian newspaper.

The statistics reveal the shocking extent of the loss of Britain’s woodland in recent decades, yet, with an obvious irony, ideas for solutions to some of our most pressing environmental issues are clearly visible within the statistics themselves:

In the last century, Great Britain lost 90% of its coppiced woodland.(1)

Half of the UK’s ancient woodland has been lost or damaged in the past 70 years. Since 1999, 276 ancient woods have suffered loss or damage, with another 588 still under threat. Currently, 85% of ancient woodland is unprotected by government legislation.(2)

There are approximately 130 million native ash trees at risk from {the disease called} Ash Dieback, which would also affect more than 1,000 {wildlife} species associated with ash, some of which are entirely or heavily dependent on it.(3)

Modelling around the river Parrett in south-west England found that floodplain woodland could increase flood storage by 71%. In cities, the addition of a street tree could reduce storm water runoff by 50-62% in a 9 square metre area, compared with asphalt alone, according to test plots in Manchester.(4)

595 million tonnes of CO2 are stored in UK forests, and net uptake per year is between 9 million and 15 million tonnes. The Committee on Climate Change’s guidelines are that abatement of CO2 is deemed cost-effective at anything less than £100 per tonne; woodlands planted for multiple objectives can additionally deliver carbon abatement at significantly less than £25 per tonne. (5)

On the positive side: coppicing schemes like this one in Whitehill Wood, can provide wildlife habitat, environmentally friendly building materials and biofuels. Image copyright © 2015.

On the positive side: coppicing schemes like this one in Whitehill Wood, can provide wildlife habitat, environmentally friendly building materials and biofuels. Image copyright © 2015.

However, for residents of Bridge and the rest of the Kent Downs AONB there is some good news. Our AONB has one of the highest levels of woodland in any of the UK’s AONBs. Furthermore, the management team, in conjunction with local authorities and landowners, is targeting the production of woodland biofuels as a growth area with great potential for the future.

Sources referenced:
Main article:
JNCC report No. 483
(4) Thomas, H. & Nisbet, T. (2007) Water and Environment Journal, 21: 114-126; Armson, D.
et al. (2013) Urban Forestry and Urban Greening, 12: 282-286


The catkins of the Hazel

Hazel catkins in Whitehill Wood. Image copyright © 2016

Hazel catkins in Whitehill Wood. Image copyright © 2016

At this time of year the sight of Hazel catkins blowing in the breeze lends an air of fairytale magic to any woodland walk, and this sense of otherworldliness about the Hazel tree was not lost on our most ancient peoples: the Celts, the Romans, the Anglo Saxons and the Norsemen all held the Hazel in high esteem as a tree of sacred magic and wisdom. The enchanting sight of hundreds of quivering catkins can be experienced in Whitehill Wood this week, where these trees grow in abundance, but even a little stroll along Bourne Park Road reveals the odd Hazel or two blooming in the hedgerows and copses at the roadside.

Catkins are essentially a row of single sexed flowers which hang on a thread waiting for the wind to catch them and spread their pollen to pollinate a flower of the opposite sex. Hazels have both male and female flowers on them but cannot self pollinate, so the pollen needs to blow across to another tree. The text books tell us that because trees with catkins are pollinated in this way, they do not need to be brightly coloured or heavily scented like roses or apple blossom in order to attract bees and other insects to pollinate them but, caught in the light of a low winter sun, Hazel catkins look as delightful and colourful as any summer flower.

A female flower on the hazel tree. Whitehill Wood. Image copyright © 2016

A female flower on the Hazel tree. Whitehill Wood. Image copyright © 2016

On the Hazel tree the male catkins are easily recognisable, resembling pale yellow lambs’ tails hanging in groups off the branches. The female flower is more difficult to spot and is more like a little bud which opens to a crimson flower ready to catch the wind blown pollen from the male catkin of another tree. From this flower a hazelnut will grow: sometimes called a ‘cobnut’ or ‘filbert’ according to the species. Unless harvested by humans, this nut will fall to the ground, to be eaten by mice or buried by squirrels who, having stored them for winter, might just forget where they put them, thereby allowing the nut to germinate and sprout another Hazel sapling.

Behold Sequoia, redwood king

Giant Sequoias on the Bifrons Estate, Patrixbourne.

Giant Sequoias on the Bifrons Estate, Patrixbourne.

Amongst the most magnificent of all the world’s trees must be the Giant Sequoia, famously of the Sierra Nevada mountains in California; but residents of Bridge, Patrixbourne and Bishopsbourne may be surprised to know that we have several here in our own little section of the Nailbourne Valley. In this cold season, amid our native leafless deciduous trees, these evergreen members of the redwood family stand out proudly against the winter sky. In the right conditions a Giant Sequoia can live for 3,500 years and reach a height of over 200 ft, with a trunk diameter in excess of 50 ft. Surprisingly, these are not the world’s tallest trees (the Coast Redwoods of the same family are) but, measured by volume, mature specimens of Giant Sequoia are the largest life form in the world. Our own examples are very young and small by comparison.

Bridge Place with a Giant Sequoia beside it (left) and another smaller one in the garden (far right).

Bridge Place with a Giant Sequoia beside it (left) and another smaller one in the garden (far right).

There are at least six Giant Sequoias in the grounds of the old Bifrons House, one of a similar age in the gardens of Bridge Place and another near the lake at Bourne Park. We understand from the current owner of Bridge Place that their tree is mentioned in the deeds as having been planted in the 1850s, and it just may be that we can determine the actual year because of one remarkable event. Although sightings of Giant Sequoias were reported by a couple of explorers in California in 1851, the official discovery of the tree by Europeans was in 1852 and historical records show that in 1853 a large shipment of Sequoia seedlings was brought over from America by an entrepreneur called William Lobb, to the delight of aristocratic stately home owners who bought them up and planted them in large gardens right across England. Could it be that the main group of Giant Sequoias in our area came from that one shipment? In those days they would have been called Wellingtonias, in tribute to the recently deceased Duke of Wellington, and that name has persisted in popular usage in England to this day; although botanically it is incorrect, for it belongs to another plant entirely.

Of course the indigenous people of California knew all about the Giant Sequoia trees long before the Europeans arrived and a more interesting name for them is the ‘Wawona’, a Yosemite Indian name that imitates the sound of the Northern Spotted Owl, which was believed to be the guardian of the forest. However, they were eventually named in honour of a native American scholar called Sequoyah, who devised a system for putting the Cherokee language into writing.

Despite native reverence for these giants of the mountain foothills, almost as soon as they were discovered, the ‘new Americans’ rushed to chop the Giant Sequoias down in a frenzy of destruction, even though the wood was of little use or value.

Object of beauty. The Giant Sequoia cone.

Object of beauty. The Giant Sequoia cone.

To a great extent we have a man called John Muir to thank for the preservation of the trees in their natural home. He was a writer and naturalist, of Scottish descent, who pioneered environmental conservation and preservation of wild spaces in the United States. His books achieved huge popularity in the 19th century, inspiring the movement to preserve the Sequoia National Park, the Yosemite National Park and other wilderness areas in America. John Muir famously called the Giant Sequoia “the king of all conifers” and “the noblest of a noble race”.

In recent decades two more Giant Sequoias have been planted in our area: one in the gardens of Bridge Place and another beautiful specimen, planted twelve years ago, in a field beside the Bourne Park Road.

This much younger Giant Sequoia was plated 12 years ago in a field off Bourne Park Road.

This much younger Giant Sequoia was plated 12 years ago in a field off Bourne Park Road.

The lichen tree of Star Hill

A small lichen covered tree on Star Hill, Bridge.

A small lichen covered tree on Star Hill, Bridge.

For those who love the luminous colours of summer’s flowers, Nature’s winter fashions can seem very drab, but it is not really so, colour can be seen everywhere if we keep a look out.

Just across the road from St Peter’s Church in Bridge there is a lodge on Star Hill. Walk up the grass beside it and as you pass it in the hedgerow on your left you may see the small yellow tinted tree pictured above. The tree stands out because it is covered in a lichen called Leafy Xanthoria (Xanthoria Parietina), a species of the large Xanthoria family, one of the most common lichens in the UK. It can often be observed on walls and roof tiles and it is present throughout the year on trees too, although more visible in winter when the leaves have fallen.

Lichens are not single organisms, they are a partnership of several organisms, usually a fungus, an alga and/or bacteria, which live together in a mutually benefiting relationship. The lichen fungus requires sugar as a food so it provides a stable home for the other partners called ‘photobionts’ which provide simple carbon sugars through photosynthesis (making food from elements in the air by using sunlight). Xanthoria lichen fungus is particularly known for thriving in nitrogen rich locations caused by bird droppings, and it is very tolerant of pollution, which is why it is so often seen on buildings in urban areas. Xanthos means ‘yellow’ in Greek and the lichen’s name and yellow colour come from Xantharina, a chemical which is thought to protect the lichen fungus from UV radiation sent from the sun. Where the lichen is growing in more shaded areas it produces less of this chemical protection and is more grey-green in colour.

Leafy Xanthoria. Note the little cup shapes which contain the spores. Image copyright © Mike Burns-Stark 2015.

Leafy Xanthoria. Note the little cup shapes which contain the spores. Image copyright © Mike Burns-Stark 2015.

Modern scientific studies have shown that lichen fungi will choose different partners to work with depending on the environment they are living in, and in consequence identifying them all is rather difficult, but there are thought to be about 28,000 forms of lichen worldwide. Like mushrooms and other fungi, lichens reproduce by distributing spores and in the case of Leafy Xanthoria these are contained within the little cup shaped forms called ‘apothecia’ which are visible in the picture above.