The Trees of Canons Park

There are well over a thousand adult trees in Canons Park. Some were planted recently but the majority date back decades, even centuries. Many are native to the UK, whilst others originate in Europe, the Americas, China and Japan and were brought to the UK as specimen trees by the Duke of Chandos and successive owners of the Canons Estate. 

Our new tree identification leaflet will help to identify some of the more common trees in the park but there is not enough space to feature every species so we have added below information on a number of additional examples that you might find of interest.  See if you can spot them around the park! Find the leaflets next to our notice board on the walls of the Bothy compound, or click on the images in our Gallery.

 ​We thank Ezra Davies for supplying this information about the trees of Canons Park.

IF YOU WOULD LIKE TO DONATE A TREE TO THE PARK, PLEASE GO TO harrow.gov.uk AND SEARCH FOR ‘TREES FOR STREETS’ 

Terms explained:
 In tree headings: 
D = Deciduous, where the tree loses its leaves each autumn/winter after they have turned colour and new leaves appear in spring.
E = Evergreen, where leaves remain green all year round and do not fall in any great quantity from the tree.
 Leaf shapes:
Ovate: diamond or triangular shaped
Palmate: shaped like the palm of the hand
Lobed leaves: Where the outline of the leaf has deep indentations which are rounded or pointed.

Swamp Cypress or Bald Cypress          Taxodium distichum  (D)      Location: in front of the Temple building
This remarkable specimen is one of the finest and oldest examples in Britain.  It is a deciduous conifer.  The needles are green during the summer, then turn a magnificent copper colour in mid-November, only to fall, making spectacular swathes of copper-coloured needles below the tree.  The cones are shaped in such a fashion that links it to the giant Redwoods of America and the mighty Cryptomerias of Japan.   It is native to the swamps of Florida in the USA.  It is known to grow out of deep water, with buttressed trunks and mighty boughs.  Alligators and Burmese pythons are known to swim between the trees in the Everglades in Florida.  Another spectacular feature of this type of tree only shows itself when the tree grows in a swamp.  There are two ancient specimens that are dated to around the1750s in Syon Park in West London.  They have grown strange woody growths that rise from the roots around the base of the tree, known as ‘knees’, the tallest being slightly over a metre tall.  It is suspected that they might be pneumatophores that aid aeration of the roots, but research is not conclusive.  The large Taxodium specimen in the park has a girth larger than the two in Syon, so that lends strong evidence that it was planted during the time of the Duke of Chandos in the first half of the 1700s.  There is another beautiful example of this tree nearby, which is probably of different origin because it seems to progress to autumn colours at a different time.
 
Cedar of Lebanon          Cedrus libani (E)      Location: in front of the Temple building
General description: Native to the Eastern Mediterranean, this cedar probably dates to the 18th century and the species was a popular decorative tree on major estates such as Canons at the time.  Although it has now lost some of its branches and has an interesting ‘ghostly face’ on its trunk, it is still an impressive tree. Cedars can grow up to 35m.  Leaves: dark grey-green needles with transparent tips, arranged in spirals around side shoots in rosettes or clusters along the twigs.  Barrel-shaped cones have a flattened top and a papery feel.

The cedar of Lebanon was an early introduction to the British Isles.  It is native to the Eastern Mediterranean, hence its name.  It is described in the Bible and the size, strength and resilience of its timber made it the tree of choice when King Solomon built the First Jewish Temple in the Land of Israel and also when King David built his palace at the top of the recently excavated City of David.  The specimen may well date to the 18th century, like its neighbour.  Whilst this specimen has lost many of its mighty boughs, it is a truly spectacular tree, probably planted contemporarily to the one in the grounds of North London Collegiate.  The barrel-shaped cones shed their winged seeds while still on the tree, so that they catch the wind and scatter far and wide.  It is closely related to the other two types of cedar in the park: Deodar Cedar and Atlas Cedar.
 
English Yew          Taxus baccata (E)             Location: Pleasure Garden, against the railings bordering NLCS
General description: Yew is a native tree, toxic to animals and humans, but birds can eat the fleshy part of the fruits that surround the poisonous seeds.  Traditionally grown in churchyards, the examples in the park are mainly found inside and to the north of the George V Memorial Garden.  Leaves: straight, small needles with a pointed tip – dark green above and green-grey below and grow in two rows on either side of each twig. Male and female flowers form on separate trees, visible in March and April. Male flowers are small white-yellow globe-like structures; female flowers are bud-like and scaly, green when young but becoming brown and acorn-like with age.

English Yew is native to Europe, including the British Isles.  Every part of the tree is toxic to animals and humans, except perhaps the fleshy part of the fruits that surround the poisonous seeds.  The seeds pass through the guts of birds and seem not to harm them.  Many books warn people not to try the fruits.  Because of its toxicity and perhaps because of folklore and pre-Christian traditions, yew trees are traditionally grown in churchyards, where animals are not allowed to graze, lest they become poisoned.  Before the Duke of Chandos built his palace, we know that this site was owned by the church, hence the origins of the name ‘Canons’.  It is very possible that some of the many yew trees on this site descend from the original church yew trees that grew here.
 
Unusually among trees, yew tree specimens are dioecious which means they are either male or female, whereas most trees are monoecious (they have both sexes on the same tree).  Female specimens produce striking red berries, and males only produce pollen.  During Spring, the male produces clouds of yellow pollen when the branches are flicked.  One of the alkaloid poisons contained within the plant is an oil called Taxane.  This is used as a constituent of chemotherapy treatments because it disrupts cell-division, especially of cancer cells.  The wood of this tree is beautiful and scented, although poisonous.  Branches of this tree were famously used for the longbows that were thought to be crucial to the success in the Battle of Agincourt.  Many a schoolboy has fashioned a bow from this fabulous tree.
 
Horse Chestnut or Conker Tree                    Aesculus hippocastanum (D)   Location: by the gates to Donnefield Avenue entrance
General description: These impressive trees can live for up to 300 years and grow up to 40m in height, and are famous for their red-brown conkers – the fruits of the tree – which develop inside a spiky green husk that falls to the ground in the autumn.  Leaves: 5 – 7 ‘palmate-shaped’ and spread from a single stalk.  They are mid-green and have softly serrated edges.  Flowers appear in May: tiny white flowers combine to form a large upright cone shape.

Although not native, this tree is widely naturalised in this country.  Generations have used the hard round nuts to play the popular children’s game of conkers.  Recently, this type of tree has become attacked by a tiny caterpillar that lives inside the leaf and creates brown spots on the leaves.  Later in the year, clouds of tiny moths emerge and lay their eggs ready for next year. 
 
Turkey Oak              Quercus cerris (D)    Location: Pleasure Garden
This mighty oak tree is a close relative of the English Oak, although it comes from Turkey and was introduced to this country in the 1700s.  One particular specimen has some spectacular marks on its trunk that show scars that have completely healed over.  There are some other specimens of this tree that might have been planted at a similar time.
 
Silver Birch         Betula pendula (D)   Location: opposite adventure playground
General description: Silver birch is a striking, medium-sized deciduous tree. When mature they can reach 30m in height, forming a light canopy with elegant, drooping branches. The white bark sheds layers like tissue paper and become black and rugged at the base. Leaves: light green, small and triangular-shaped with a toothed edge, which fade to yellow in autumn.  The flowers (catkins) appear from April to May. Male catkins are long and yellow-brown in colour, and hang in groups of two to four at the tips of shoots, like lambs’ tails. Female catkins are smaller, short and bright green.

This beautiful tree, named after its silvery bark, has a special strategy: it is a pioneer tree.  The tree produces vast quantities of seeds on its long catkins that disperse far and wide.  The seed remains fertile for a long time, but only germinate whenever a tree falls, allowing light to fall on the woodland floor.  The seeds germinate quickly before any other tree has a chance and form dense thickets of saplings (young trees).  As they are the first to colonise, they are known as pioneer trees.  They only live about 50-70 years and eventually get replaced by other trees.  Meanwhile, the birches have dispersed and sown their seed ready waiting for the chance to grow after another big old tree falls.  The bark of this tree was used for weaving bags and baskets and for making tiles in prehistoric times and is still used in Nordic countries to make traditional baskets and knapsacks.  The wood has a pleasant light colour.
 
English or Pedunculate Oak        Quercus robur (D)       Location: along the grassy ‘camber’ leading to Whitchurch Lane
General description: Oak trees can live over 1000 years and have become a symbol of England for centuries. Leaves: around 10cm long with 4–5 deep, rounded lobes around each side. The leaves have almost no stem and grow in bunches.  Long yellow catkins distribute pollen into the air in spring.  Acorns in hemispherical cups fall to the ground in autumn and sprout the following spring.

This tree has been used as a symbol of England for centuries.  The familiar lobed leaves, acorns enjoyed by pigs and gnarled character make it one of the most iconic and recognisable trees.  Its strong robust wood was used to build cathedrals and boats and was an important factor in making Britain the most powerful seafaring nation for many centuries, until steel ships were first invented.  In many old houses, curved beams can be found, recycled from old decommissioned ships.  The oaks of old were pollarded (cut every hundred years) just above the height of horses’ hungry mouths.   This led to lots of curved boughs, ideal for ship-building.  Some of our oldest oaks are remnants of these trees that were regularly pollarded.  This technique is actually thought to prolong the life of these trees.  Oak trees are full of wildlife.  Some experts think that the first oaks were brought to England during prehistoric times, just after the last ice age.  The acorns are inedible to humans, unless the tannins are leached out by placing in a bag in a river and then the acorns are roasted over a fire. 
 
Ash           Fraxinus excelsior (D)   Location:  along the grassy ‘camber’ leading to Whitchurch Lane
Ash is perhaps the commonest tree in England: about a third of all trees are this species.  It is vital for the character of the English character and wildlife because it is the last tree to come into leaf in the spring.  This allows a wide variety of wild flowers to bloom, such as bluebells, anemones and celandine before the tree’s leaves finally emerge.  If you go to an ash woodland in spring, you will see wildflowers, contrasted with a beech woodland, which has few wildflowers.  There is an old saying: “Oak before ash, and we’re in for a splash; ash before oak, and we’re in for a soak.”  It means that usually the Ash leaves emerge long after the oak leaves and this signals a normal English summer, with a splash of rain.  If, on the other hand, the ash sprouts leaves before the oak, then this signals a very wet summer ahead and we will have a ‘soak’, instead of a ‘splash’.   This species of tree has suffered across Europe in the last ten years due to a disease called ‘Ash Dieback’.  This disease has wiped out 90% of ash trees in Denmark and Poland.  The disease has now arrived in England and is present in our park.  The stakes are very high, especially as a third of our trees are at risk; however, there are some signs that the English population is more genetically diverse than the Polish and Danish populations and some might be resistant.  This could mean that some English ash trees might offer hope in the formidable task of repopulating Europe with disease-resistant trees, which will allow woodland wildflowers to remain a feature of Europe’s woodlands. 
 
Monkey Puzzle        Auracaria aracana (E)       Location: south of the Bothy building
This fabulous tree is our only tree hailing from South America. Many centuries ago, its edible nuts were brought to England and planted.  Our specimen is old enough to produce fruit which are large and rounded and are found high in the tree.  The main problem is harvesting the fruit because the tree has so many spiky leaves that climbing the tree is practically impossible.  The entertaining name derives from its unusual shape, though even monkeys might have a problem climbing its spiky branches.  It is known to be quite ancient in the fossil record, but widely planted in Victorian times.  It grows very slowly at first, then forming a spectacular dome and ending up like a flat-topped mushroom.
 
Bottlebrush Buckeye       Aesculus parviflora (D)       Location: opposite gates to George V Memorial Garden
This entertaining tree is a relative of the conker tree, of which the park has many fine examples.  This much smaller species tends to form large suckering thickets with spectacular candle-shaped ‘bottlebrush’ inflorescences (flowers) that attract plenty of bees and hornets that predate on bees.  It is native to the USA, specifically Alabama and Georgia and overlaps with our spectacular Swamp Cypress and Catalpa bignioides. 
 
Southern Magnolia       Magnolia grandiflora (E)   Location: George V Memorial Garden
General description: Magnolias can be evergreen or deciduous and the George V Memorial Garden features a number of each type.  They are some of the oldest flowering plants – dating back 95 million years – and this particular species is evergreen, producing fragrant ‘dinner plate’-sized white flowers with a touch of pink.  Leaves: dark green, ovate, leathery and stiff, 6 – 12cm and with smooth outlines. All the magnolias in this garden flower around May.
This species of Magnolia is native to the whole of south eastern USA, and partners some of the other trees close by in the park.  Magnolias are are pollinated by beetles that evolved early in Earth’s natural history of flowering plants, after the reign of the conifers. This particular magnolia is evergreen and is known to produce fragrant ‘dinner-plate’-sized flowers.
 
Magnolia (D)       Location: George V Memorial Garden
Magnolias are some of the earliest flowering plants to evolve, 95 million years ago.  The park has several spectacular examples that flower in May.  They are pollinated by beetles and often have a melon-like scent. The leaves can vary in shape but are usually leathery and stiff, dark green and fairly large.  Flowers vary from white to pink and are fairly large.
 
Chinese Tulip Tree       Liriodendron chinense (D)
There are only two species in this genus, which is related to Magnolias.  There is one species native to USA and our example that is native to China.  There used to be a continuous band of these trees across the Northern Hemisphere, but now there are only two species in existence, in the USA and China.  The strange flowers are held high in the air and are hard to examine closely. The leaves are very distinctive: our example having the larger and more spectacular leaves.
 
Ginkgo       Ginkgo biloba (D)        Location: north-wetern corner, outer wall, George V Memorial Garden
This ancient tree is planted in Chinese temples and is very ancient indeed. Unusually among trees, the male and female forms are on separate trees, whereas many trees show male and female flowers on the same tree.  Ours produced fruit which identifies it definitively as a female.  The fruits have a remarkable smell resembling rancid butter, but nevertheless it is used in Chinese medicine.  The leaves turn a spectacular butter-yellow in autumn.
 
Weeping Golden Willow        Salix x sepulcralis ‘Chrysacoma’ (D)      Location: Along the grassy ‘Camber’ leading to Whitchurch Lane
General description: This graceful tree can grow up to 25m tall and can also be found in the children’s playground of this park. It grows rapidly, but has a short lifespan of between 40 and 75 years. The leaves are long, narrow and light green, alternate and spirally arranged along the stalks.  They turn a gold-yellow in autumn before falling. The flowers are arranged in catkins produced early in the spring.
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This is a hybrid willow, hence the ‘X’ in its name.  That means it is a cross between two different species.  Its majestic hanging branches make it a very iconic tree.  Its parents originate from China and were traded along the Silk Road across to Babylon and eventually to Europe.  It was thought to be the willow trees in the psalm that talks about the rivers of Babylon, where the children of Israel were enslaved.  Nowadays, it is thought that the weeping trees that the Israelites hung their harps were in fact poplars, that resembled willows.  Nevertheless, the Weeping Willows are one of the most spectacular trees grown in England. 
 
Common Hawthorn  (May Tree)      Cretaegus monogyna (D)    Location: south of the George V Memorial Garden
General description: The Hawthorn (or May) Meadow just south of the walled Memorial Garden was probably planted around the 1950s and looks at its best in spring, when the trees are covered in pretty pale-pink blossom. They can reach a height of around 15m and their twigs are covered in thorns. Leaves: around 3-6cm in length, ovate-shaped with deep lobes, turning yellow before falling in autumn. Flowers are highly scented, white or occasionally pink, with five petals, growing in flat-topped clusters. Hawthorns develop deep-red berries in autumn.

The park has an area known as the Orchard.  Actually the trees produce fruit that although  edible, are so small that they are barely worth picking.  During WW2, parts of Europe were so poor that children were told to eat this fruit to avoid starvation.  Little is known why the park has an orchard of these trees.  They remain an enigma, due to their small and mean fruit.
 
Lime Tree        Tilia (D)          Location:  south-east corner of the George V Memorial Garden
The park’s poorly-named Lime trees are not closely related to true limes that are, of course, citrus fruit.  The European types of Lime tree, also known as the Linden, are used in medicine and produce heart-shaped leaves and sucker from the base.  They attract lots of greenfly that exude sap enjoyed by ants, but not enjoyed by anyone foolish enough to park their car underneath. 
 
Wellingtonia       Sequoiadendron gigantea (E)    Location: south of the Bothy building
General description: These are some of the tallest species in the world (50 – 90m), and first came to the UK from the Western USA in the mid-19th century and were popular additions to country estates like that of the Duke of Chandos.  They are fire resistant and extremely long-lived.  Branches sweep downwards from a cone-shaped crown.  Leaves: dark green, hard and scaly with a feather-like appearance.

Just outside the park, along Canons Drive, is one of England’s finest avenues of Wellingtonias.  These were probably planted in the mid-19th century, when this species was first brought to the UK.
 
Pin Oak        Quercus palustris (D)
This oak has spiky leaves, as opposed to the familiar lobed English Oak.  The branches start off vertically facing and then start to droop lower and lower as the tree matures.  It has spectacular red autumn foliage and has a special shape, unique to this kind of oak, hailing from the USA.
 
Common Beech         Fagus sylvatica (D)
General description: Beeches form majestic trees, reaching up to 40 metres and home to rare forms of wildlife. Leaves: 4 – 9cm long, oval shape with wavy edges and deep veins, lime green and hairy when new; they lose their hairs as they mature. Some beech trees hold on to their leaves throughout the winter. Flowers: tassel-like male catkins hang from long stalks at the end of twigs, while female flowers grow in pairs, surrounded by a cup.
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This beautifully architectural tree has mighty grey boughs and leaves that cast a heavy shade, stopping plants on the woodland floor from growing; moreover, beech leaves emerge early and the leaves that fall are allelopathic (they contain natural chemicals that inhibit other trees from growing), therefore the woodland floor will have fewer plants.  Beech woodland is usually open and plain, with dapple sunlight on bright days.  The nuts are edible to humans, but the tree has a strategy of making most of its nuts without a kernel, so that hungry squirrels (or humans)  give up bothering to open them.  This allows the tree to lose fewer of the nuts.  Some experts think that the range of beech trees will shift northwards if the climate changes because beeches don’t tolerate dry conditions, and that is partly why England, especially Western England is the perfect place for it, due to its relatively high summer rainfall.  Its wood is strong and thick.
 
Common Hornbeam         Carpinus betulus Fastigiata (D)     Location: opposite the adventure playground
General description: Common hornbeam is a deciduous tree, which has pale grey bark with vertical markings, and sometimes a short, twisted trunk that develops ridges with age. Mature trees can reach a height of 30m and live for more than 300 years. Leaves have a pleated look and are similar in shape to beech leaves – oval with pointed tips – but Hornbeam leaves are smaller and more deeply furrowed than beech leaves and have finely toothed edges, whilst beech leaves have wavy edges. They become golden yellow to orange in autumn and most stay on through the winter. Male and female catkins are found on the same tree. After pollination female catkins develop into papery, green winged fruits.

The Hornbeam is native to England and grows in our woodlands.  Traditionally it was coppiced or pollarded.  Its wood is very hard and therefore useful for tools.  It burns slowly and with great heat.  In the park, most of our hornbeams are fastigiate (upright) in form.  This tree is widely planted in parks, due to its decorative outline and yellow autumnal foliage.  

 Italian Poplar         Populus nigra var. italica (D)
General description:  Also known as the Lombardy popular, ‘Italica’ is a tall, narrow deciduous tree that can grow to 30m tall.  Leaves: bright green diamond to triangular shape, 5 – 8 cm long and 6 cm across.  The ornamental crimson male catkins appear before the leaves open in early spring. Female catkins are soft and cotton-wool-like and blow freely in the spring winds.

Sycamore        Acer pseudoplatanus (D)   Location: behind the Temple building
General description: These trees can live for up to 400 years and reach heights of around 35m.  They provide a good habitat and food source for many kinds of wildlife.  Leaves: Palmate shaped with five ‘lobes’, around 7 – 16cm, with young stalks reddish in colour. Small, green-yellow flowers hang in spikes, or ‘racemes’ and after pollination by wind and insects, female flowers develop into small brown winged fruits that fall from the trees like little helicopters.

London Plane         Platanus × acerifolia (D)
General description: As the capital’s most iconic tree, this is a hybrid of American Plane (in USA called a sycamore) and Oriental Plane from Asia Minor, and was first discovered in the 17th century, then widely planted in the 18th.  It can grow to 35m and lives for several hundred years.  Leaves:  sycamore-like leaves are leathery and thick, with five triangular lobes. They turn a rich orange-yellow before falling in autumn. Female flowers develop into spiky fruits, comprising a dense cluster of seeds with stiff hairs.

Large Leafed Lime         Tilia platyphyllos (D)
Despite the name, this is not related to any citrus and is better-named Linden.  There are many types of lime.  It is possible to tell true species apart by the underside of the leaf. Common lime (Tilia x europaea) has tufts of white hairs between the vein joints, whereas these are rusty red in small-leaved lime (Tilia cordata). Large-leaved lime has hairs all over the underside. Common lime is a hybrid and is rare in the wild in the UK, but is often planted in streets and parks. 

Tree of Heaven          Ailanthus altissima  (D)     
This tree is native to Northern and Central China, Korea and Taiwan.  It has compound leaves, which means that each leaf is divided into leaflets.  It grows very quickly to find light and suppresses other trees from growing underneath, using natural chemicals in its leaves.  It is famous in China because all parts of the tree give off an unpleasant odour.  It suckers prolifically and can form large thickets.  There is a kind of large silk moth called the Ailanthus Silk Moth that feeds on this tree during its caterpillar stage.  It produces excellent silk that is stronger than regular silk, although not as lustrous and unable to be dyed effectively.

Deodar Cedar         Cedrus deodara (E)
The Deodar grows native in the foothills of the Himalayas in Pakistan and India.  It is famously seen in some of the hill stations used by the British during colonial times.  It is related to the other two types of cedar in the park.  There are some spectacular specimens to be found in Canons Drive.
 
Atlas Cedar         Cedrus atlantica ‘Glauca’ (E)
The Atlas Cedar is the only African tree in the park.  It grows high in the Atlas Mountains of Morocco.  The mighty boughs and branches are reminiscent of the pounding waves of the Atlantic Ocean. It is related to the other two types of cedars in the park.
 
Japanese Maple        Acer palmatum (D)
The Japanese Maple was introduced to England in the mid-1800s.  The specimen here might well be one of the first to arrive in this country.  It produces small winged seeds that rotate helicopter style as they fall to the ground.  In autumn, the leaves turn spectacular colours.
 
Dawn Redwood         Metasequoia glyptostroboides (D)
This fabulously named tree was only known from fossils 150 million years old, until the twentieth century, when small numbers of living specimens were discovered in Central China in wet lowland slopes.  It is therefore regarded as a ‘living fossil’.  Now it is widely planted, especially because it is fast-growing and highly ornamental.  It is distantly related to the nearby Swamp Cypress.

Indian Bean Tree        Catalpa bignioides (D)
This entertaining tree doesn’t come from India, despite its misleading name, but from the USA (Alabama and Mississippi).  Its range overlaps with the Swamp Cypress, of which we have one of England’s finest specimens.  It has fragrant white flowers and spectacular long fruits that resemble giant beans, though inedible. 
 
Northern Catalpa (Northern Indian Bean Tree)       Catalpa speciosa (D)
This is a rare species related to Catalpa bignioides.  It is native to areas of USA further north and has distinctive leaves and flowers.  Its fruits are spectacular long bean-like pods and its overall appearance is of a large-domed tree.  It is one of the finest specimens of this rare tree in England.