One of the aims of The Year of the Tree is to promote awareness  and knowledge of trees.  With this aim in mind, we will feature an indivudual tree or species of tree each week during 2007.   The tree will also be featured in the Gibraltar Chronicle.

WEEK 52

Dragon Tree  Dracaena draco                                            Garrison Library gardens

The Dragon Tree features elsewhere in this series, but this particular specimen is worthy of mention in view of its unusual form.  Dragon trees tend to branch after they flower, but very occasionally, individual trees fail to flower and therefore to branch, and continue to grow in a single-stemmed form.  There is one such specimen, now over 20m tall, in Gibraltar in the gardens of the Garrison Library.   Its tall trunk is now resting on branches of a normal specimen, probably planted at around the same time.  It is a true curiosity and a fitting specimen to end this series. 

WEEK 51

Cork Oak  Quercus suber

This is one of the most characteristic trees of the region, covering large areas of woodland in the countryside very near Gibraltar.  It is a medium-sized evergreen tree, which, although it can grow to 20m in wetter areas, is normally much less tall in the wild.  This oak is the species which produces cork, an outer layer of the bark which serves to protect the tree from fire.  This layer is harvested in the summer, every 9 to 15 years, depending on the region, and used for insulation, bottle stoppers, etc.  There are very few Cork Oaks in Gibraltar, as they generally grow in less alkaline soils than are found on the Rock.  However, there are a few, notably one in the Botanic Gardens and another on Mount Road.

WEEK 50

Date Palm  Phoenix dactylifera                                                             Line Wall Road

The Date Palm located at Line Wall Road, in the grounds of the Synagogue, is one of Gibraltar’s tallest trees and will be well over a century old.  Specimens are known to reach nearly 50 m in height.  It is a species that is native to North Africa – although the exact origin is not known.  It has for centuries been cultivated in North Africa and the Middle East for its fruit, although it is a well known ornamental tree in warmer climates around the world.

WEEK 49

Brazilian Pepper  Schinus terebinthilfolius

Probably not as well known as its relative, the so-called Californian pepper, also from Brazil, this species is probably more spectacular in appearance thanks to the bright red clusters of fruit it produces in winter.  It is a small, bushy, evergreen tree which can grow to about 9-10m.  It has dark green, compound leaves which set-off the red berries is a striking way that has led to some of its other names, like Florida Holly and Christmas Berry.  The full natural range of the species is Brazil, Argentina and Paraguay, but it is widely planted elsewhere, where it can become problematic if it becomes established in natural habitats.  This has not occurred in Gibraltar, where these are several to be seen in different locations, including the Botanic Gardens and Reclamation Road, where there are several specimens at least 50 years old.

WEEK 48

Ombu  Phytolacca dioica                                                                            Castle Steps

This is another of these South American trees which has already featured as a species, but which merits separate mention as an individual tree.  It is one of the few street trees now remaining in the northern upper Town of Gibraltar, and is another one that has been a landmark to residents through many decades.  This particular tree has been threatened with removal on a number of occasions, due to claims that its growing girth would cause damage to a retaining wall.  Fortunately alterations to the wall have ensured that it is safe for the moment. 

WEEK 47

Ombu  Phytolacca dioica                                                                                    Landport

This is a South American species which has already featured, but several individual trees will be highlighted because of their prominence in Gibraltar.  The specimen of Ombu located at the northern approach to the access into Gibraltar, in the area known as Landport, is one of the largest in Gibraltar, and probably one of the largest in the region.  It is likely to be over 100 years old, and has a massive base to its trunk.  Sadly, due to repeated pollarding, much of the foliage looks quite young and it lacks the twisted upper branches of the few specimens that have escaped such management in the past.  Nevertheless, it is a specimen tree that has greeted thousands of people through the decades as they have gone about their business entering and leaving Gibraltar from Spain and therefore deserves special mention.

WEEK 46

Bunya-bunya Tree  Araucaria bidwillii

This is a distinctive conifer with dark green foliage, often confused wioth its relative, the Monkey Puzzle Tree Araucaria araucana.  They are native to Queensland, Australia, where they form part of the rainforest community.   Most striking perhaps are the very large pineapple-shaped cones, about 25cm long and 20 cm wide, and which can weigh up to 8kg.  The trees, with typically dark green foliage, can grown to up to 35 m in height.  Until they are about 8-10m tall, they retain the typical conical “Christmas Tree” shape, but after that height they tend to lose the lower branches, and develop a dome- shaped head.  This is already happening to the only Bunya-bunya in Gibraltar, which grows within the grounds of the Governor’s residence, The Convent. 

WEEK 45

Dwarf Fan Palm  Chamaerops humilis 

This plant is a true native of Gibraltar, with the local name of “palmito”, and indeed of the Mediterranean region in general, from Morocco and Iberia to Turkey.  Generally associated with matorral or scrub vegetation, it is a resistant plant, with some populations surviving the cold in high mountains.  In many areas it is typically found as a small shrub, without any trunks.  This could be due to exposure or grazing, but is very often as a result of the plant being cut back to collect palm hearts, which are considered a delicacy.  In Gibraltar this practice has been largely lost, and in any case many specimens grow in inaccessible crags on cliffs.  There are therefore some fine specimens of Dwarf Falm Palm on the Rock, many consisting of clusters of well grown miniature palm trees with clearly developed trunks of up to 2m in height.  The species is increasingly popular in cultivation, including as an indoor plant in cooler regions.

WEEK 44

Jerusalem Thorn  Parkinsonia aculeata

This is a small, spreading tree that will grow to about 8 metres in height.  One of the main features of this tree is that the more slender branches and twigs are green, and not brown or grey as is the case with most trees.  This has given it its Spanish name of “palo verde”, or “green stick”.  This species is a native of Mexico and the south-west United States where it grows in desert grasslands.  It is grown elsewhere in many tropical and sub-tropical areas.  In some of these, such as parts of Australia and the south-east United States, it is an unwelcome invasive species that displaces native flora.  In cultivation, however, its green bark, feather-like foliage and bright yellow flowers in spring make it very acceptable.  There are very few Jerusalem Thorns in cultivation in Gibraltar, one of the best specimens belong located in the Botanic Gardens.

WEEK 43

Orchid Tree  Bauhinia variegata 

This small tree, which can grow from 6 to 12m, and is also known in English by its first Latin name, “Bauhinia”, is not an orchid at all, despite the orchid-like flowers, but a relative of the peas and brooms.  The blooms are striking pink and white, and appear towards the end of winter.  The leaves are unusual in that they are double-lobed. The are dropped briefly in the colder months.  Its relative, possibly a hybrid with another Bauhinia species B. purpurea, is Bauhinia blakeana, which is native to Hong Kong and is its national flower.   This species has recently been planted for the first time as a street tree in Gibraltar’s town centre.

WEEK 42

Cape Chestnut  Calodendrum capense

This tree, a member of the same family as the Citrus species, comes from the Cape region in South Africa, and therefore grows well in our climate.  It also extends up the eastern Cape into tropical Africa and on north to Ethiopia.  Its scientific name means literally “beautiful tree from the Cape”.  It has large, leaves similar to a chestnut tree (to which it is not related) , and the trunk is smooth and mottled grey.  In open locations it will grow to about 7m, but in closed forest can reach 20m in height.  When in flower in early summer, it becomes covered with its pale pink blooms.  There are very few Cape Chestnuts in Gibraltar, two of these being located in the Botanic Gardens.

WEEK 41

Weeping Fig   Ficus benjamina 

Also known as the Benjamin Tree or the Tropic Laurel, among several other names, the weeping fig has long been a favourite houseplant, with lush, shiny dark green foliage.  Increasingly variegated varieties have been grown to brighten up dark corners.  In our climate it does extremely well outdoors, best in semi-shade, although it can also do well in shade and even in full sunshine if well watered.  If conditions are not right, either in regard to the amount of light, watering, or temperature, it tends to respond by quite severe leaf drop.  The tree is native to south and south-east Asia down to northern Australia.  Like many members of the fig family, it produces fruit, which are a major food item in the diet of many bird species.  Again, like many figs, it can grow into a large tree with aggressive roots, although it can be controlled through clipping and is an excellent hedge plant.  There are several examples of Weeping Figs growing as trees in the Queensway area, although the one in the photograph is situated in a small garden in Joshua Hassan House on Secretary’s Lane.

WEEK 40

Canary Island Date Palms Phoenix canariensis                                    The Mount

While the Canary Island Date Palm has been featured as a species already, these particular individual trees are highlighted here as representing possibly the finest specimens in Gibraltar.  Probably at least 150 years old, and about 20metres tall, these majestic palms add great distinction to the gardens of this former Admiral’s residence.  Date palms in general are now seriously threatened by the Asiatic Palm weevil Rhynchophorus ferrugineus, which, although not yet seen in Gibraltar, is devastating palm trees along the Costa del Sol as far south as Estepona and will doubtless soon arrive in Gibraltar.  The loss of these trees in particular will be extremely sad.  Although not native to the area, they have become a feature of the urban landscape and are much moved.

WEEK 39

Beaked Yucca  Yucca rostrata

The Beaked Yucca is a native of the Chihuahuan desert in western Texas and northern Mexico, typically growing in rocky limestone areas.  It is an impressive plant with profuse foliage.  The leaves are sharp tipped and stay on the plant after they die, giving the tree a bearded appearance.  They can grow up to five metres, with old plants branching and developing several heads.  Well known in gardens in North America, it is only now beginning to show in Mediterranean Europe, where it can grow well.  There is a specimen in the Sonoran desert bed of the Alameda Gardens, which was planted by former Governor Field Marshal Sir John Chapple as a farewell gift.

WEEK 38

Nettle Tree  Celtis australis                                                                    Europa Road

This week the tree is a specific specimen of a type that has already been covered in general terms.  It is a fine specimen of Nettle Tree located to the east of Europa Road between the Loreto Convent and the Mount.  This is a rounded, well-formed tree with a single stem, showing very clearly the grey bark so typical of the species.  The fresh spring growth lightens this corner with its shade of bright green, while in winter it displays its spreading branches after the leaves have fallen.  This is a very attractive tree and one of Gibraltar’s finest.  

WEEK 37

Strawberry Tree  Arbutus unedo

This species, native to the Mediterranean region is known is Spanish as the Madroño, as are its red, strawberry-like fruit, which are edible, and quite popular in the autumn in the region around Gibraltar where they are often seen in markets.  The Strawberry tree is not related to the strawberry, but to the heathers, and like most heathers it grows best on acidic soils.  It does not grow wild in Gibraltar, but has been brought in to a number of gardens, including the Mount and the Alameda, where a number of specimens are doing well.  It has attractive small, bell-like off-white flowers which appear on the tree in autumn together with the fruit.  The leaves are dark green, similar to those of the laurel.

WEEK 36

Italian Cypress  Cupressus sempervirens                                   

The Italian Cypress is native to the eastern Mediterranean, from Greece and Lybia eastwards to Jordan and Iran.  It has however been extensively planted throughout the Mediterranean and the warmer regions of the world, including the southern United States.  It is a conifer, producing round grey-brown cones, and has small, scale-like leaves.  It is a medium, evergreen tree, growing up to about 35 metres.  It has very dark green foliage, giving the tree a rather sombre look – perhaps the reason why it has traditionally been planted in graveyards.  The best-known form is the columnar “pyramidalis” variety, although arguably the “horizontalis”, which has spreading branches like a cedar is more attractive.    In Gibraltar there were until recently some fine spreading specimens in the Giralda Gardens on Line Wall Road, and there are still some in Loquat House in the South District, where sadly several have been lost to disease.  Italian Cypresses are in fact susceptible to both root rot and to canker. There are several good columnar specimens, including the one pictured here, which is located in the Mount.

WEEK 35

Tree of Heaven  Ailanthus altissima                              

The Tree of Heaven is a deciduous tree that is native to parts of china and Taiwan, though widely cultivated in many different climates.  It is an attractive tree, with smooth, grey bark, and large compound leaves (with a most unpleasant smell) and yellowish to reddish flowers, followed by large, winged seeds that are dispersed by the wind.  Although individual trees can be pleasant to look at, they spread vigorously, both by seed and roots suckers, and sprouts quickly when cut.  Not only does I quickly form a thicket excluding other plants, it also produces chemicals which stop the growth of other species.  In Gibraltar it was quickly colonising parts of the Alameda Gardens, although it is not controlled there.  It is however causing problems in the Mount, in the Catalan Bay area, and also on the newly restored sand slopes where control will be necessary very soon.  The leaves, roots and bark have long been – and still are – used in traditional Chinese medicine as an astringent.   The finest specimen of Tree of Heaven in Gibraltar is probably the one in the Trafalgar Cemetery where it is also controlled from unwanted spreading.

WEEK34

Mirbeck’s Oak  Quercuscanariensis

WEEK33

Seville Orange  Citrus aurantium

In Gibraltar, as in many Mediterranean towns and cities, the Seville Orange, also known as the Bitter Orange, is mainly planted as a street tree for decoration.  Itsvery fragrant flowers (“azahar”) and bright orange fruit, contracting with the dark green foliage, makes it a very attractive tree.  It is the fruit of this species that is normally the main ingredient of marmalade, but the plant has other uses as a herb. Neroli oil is produced from the flowers and Petitgrain oil from the leaves and twigs.  Some of the properties hat have been attributed to extracts from this tree include lowering of blood pressure, anti-inflammatory, antibacterial and anti-fungal activity, and lowering of cholesterol.  The Seville orange probably originated in northern India, and was brought to Europe by the Moors, so it has long been associated with Mediterranean cultures, even taking a Mediterranean name!

WEEK32

Aleppo Pine  Pinus halepensis

The Aleppo Pine is a native of the eastern Mediterranean and has a long association with Man.  Its resin was used in ancient Egypt for embalming, and it is mentioned in the Bible (which refers to it as a “fir”).  It was also a source of timber for the eastern Mediterranean civilisations.  It is a two-needled pine (its needles grow in pairs), which bears small cones which are very pointed when green but open up to almost round, remaining on the tree long after they have shed their winged (inedible) seeds.  Aleppo Pines have bee planted in Gibraltar both in Gardens (including the Alameda Gardens), and on the Upper Rock.  They are more resistant to drought than the Stone Pine, which is also planted here.  Apart from the difference in the cones, the two species can be told apart by looking at the bark.  The Aleppo’s bark is grey and rough, and does not have the large, reddish “plates” of the Stone Pine.

WEEK31

Queen Palm  Syargus romanzoffianum

The Queen Palm is a native of Brazil, Paraguay and northern Argentina, but grows well in many of the warmer parts of the world, where it is widely planted.  Indeed it is an unwelcome exotic invasive species in some parts, such as in Florida, USA.  The Queen Palm has been increasingly planted in Gibraltar over the past fifteen years or so, often replacing the more traditional Canary Date Palm, as it is not as prone to pests and disease.  The Queen Palm has graceful, plume-like leaves and is a fast grower, provided it gets water regularly.  In summer it develops feathery inflorescences, which hold the flowers, followed by bright orange dates.  In Gibraltar there are several good specimens, including some in the traffic islands near the Trafalgar Cemetery and in the Botanic Gardens.

WEEK30

Red-flowering Gum  Corymbia ficifolia

he Red-flowering Gum is a close relative of the Eucalyptus, indeed, until very recently, botanists considered it to be a species of Eucalyptus.  Like most of the rest of this group, it is a native of Australia.  In the wild it is found only in open forest in a very restricted part of the south of Western Australia.  It is fairly widespread in cultivation, where it often grows better than in the wild.  It reaches a maximum height of about 15m.  Its leaves are fairly wide, glossy and dark green.  The bark is rough and does not flake off as in many Eucalypts.  This species flowers in summer – so in Australia brightens up parks and gardens at Christmas time.  While the typical flower colour is bright crimson-red, these can vary between plants and, especially because they can hybridise with similar species, they can be white or orange also.  There are not many red-flowering gum trees in Gibraltar.  There is one above the Caleta Hotel in Catalan Bay, and another in the Australian section of the Botanic Gardens at the Alameda.

WEEK 29

Australian Flame Tree   Brachychiton acerifolius

he Australian Flame Tree is native to coastal Queensland and northern New South Wales, where it grows mainly in rainforests.  However it can grow well in other warm regions – such as Gibraltar, although here it will not generally reach the height it can achieve in the wild, where it can get to 30-35m.  the leaves are shiny and dark green, almost maple-leaf shaped (the meaning of the name “acerifolius”).  In cultivation it can survive without watering once it is established.  It does not flower every year, but when it does it will shed all its leaves and get covered in small, bright red bell-shaped flowers, which give the tree a brilliant red appearance, and is the reason for its name – Flame Tree.  Flowering is usually in early to mid summer.  There are several Australian Flame Trees in Gibraltar.  A well established one in the Botanic Gardens flowered in 2005, one along Europa Road is flowering in 2007, and there are other young trees along Queensway and below Red Sands Estate.

WEEK 28

Blue Jacaranda  Jacaranda mimosifolia

Jacarandas are impressive trees in May and June when covered in clusters of lavender-blue tubular flowers, which, in the sunnier positions, completely cover the trees.  When these fall, they carpet the ground in lilac blue.  The flowers give way in autumn to large, woody seed pods which from a distance resemble discarded tea-bags hanging on the trees.  They can grow to about 15 metres, although they are usually not that tall.  The Blue Jacaranda has large, compound leaves, which are dropped most years in phases, first the small leaflets and then the long, thin stalks.

Despite it being very common in cultivation in warm regions – it is even an unwanted invasive in parts of Australia – it is considered threatened in the wild as it originates in the endangered forests of north-west Argentina and Bolivia, which are rapidly being converted to agriculture.  There is another, similar form in Peru, while the related Purple Jacaranda, much rarer in cultivation, comes from Brazil.  There are also occasional white flowering forms seen in cultivation.

In Gibraltar there are several mature Jacarandas in the South District, which stand out when in flower in May and June and observed from the Bay.  More recently several have been planted in the Town area.

WEEK 27

Bangalow Palm  Archontophoenix cunninghamiana

Also known as the Piccabean Palm, this is a very attractive palm that originates in the  rainforests of the central eastern Australian coast.    In ideal situations it can get to t can get to 25 metres tall, with a spread of two and a half metres.  Being a rainforest  plant it does best when watered and when in a sheltered position.  In their native habi9tat they can even be seen growing inside streams.  The leaves are bright green, and the trunks are smooth and ringed with noticeable leaf scars.  They are popular in cultivation in Australia and elsewhere, but there are few well grown specimens in Gibraltar.  Two of these are in the “Dell” of the Alameda Gardens.  There is an unconfirmed story that these two were small potted houseplants given to the gardens during the second world war by an evacuee just before she left Gibraltar.  The head gardener apparently accepted them, but was unsure as to whether they would survive.  They are still there, tall, healthy palms standing at about 8 metres.  One is clearly visible from the whalebone arch just to the south of the Giuseppe Codali Bridge.  Judging from their size, they are probably about the right age for the story to be true.

WEEK 26

Black Mulberry Morus nigra  and White Mulberry Morus alba

WEEK 25

Fig Tree  Ficus carica

The common fig, a member of the mulberry family, is a native of the eastern Mediterranean which has been cultivated by Man for over 5000 years.  It produced the edible figs, which are popular fresh or semi-dry.  Two fruit crops are produced.  In spring the brevas grow from last season’s wood, and in later summer or autumn the main fruit appear on new stems of the season.  The trees are pollinated by a small wasp and only produce seed when the wasp is present.  Although eastern Mediterranean in origin they are naturalised and grow wild in Gibraltar, in several places on the Upper Rock but also in town, often in walls, where the roots can cause damage.  The leaves have a well-known characteristic shape, and carry a white, milky sap which can cause blisters on sensitive skins especially when exposed to the sun. 

WEEK 24

Oriental Plane Tree  Platanus orientalis

This is a deciduous tree, a native of western Asia, from Asia Minor to Iran, although some botanists believe it to be native in Iberia, having survived the last ice age here.  It is much planted in Europe, particularly as a city tree.  It is deciduous, so its leaves are refreshed annually and do not carry city grime year on year.  It also allows the sun through in the winter, but provides welcome shade on the summer.  The Orienatl Plane is one of the species hybridised to form the famous London Plane which graces streets, parks and squares in the British capital.  In Gibraltar it has often been planted in the past in the South District and most recently in the north end of Main Street.  There are other examples (some sadly rather badly pruned in the past) in the Garrison Library and Line Wall Promenade.  The bark of this tree flakes off in patches, leaving a dappled surface.  The leaf shape is similar to a maple, with 5-7 lobes.  The fruits, borne in summer are round and spiny.

WEEK 23

Pepper Tree  Schinus molle

A well known tree in Gibral;tar where it has been widely planted, in such places as Town Range (behind the Government offices), on Reclamation Road and Europa Road (below the Loreto Convent).  Often known as the Californian Pepper Tree, it is in fact native to South America, hence its other name of Brazilian Pepper Tree.  It is a shrubby tree with narrow compound, spiky-looking leaves which have a strong peppery smell when crushed.  It produces small off-white flowers which give way to panicles of small reddish berry-like fruit.   These berries, which have a peppery flavour, are used in syrups, vinegar, and beverages in Peru, are added to Chilean wines, and are dried and ground up for a pepper substitute in the tropics.  It is considered to have many medicinal properties.  The tree can grow to 4m to 10m with fairly dense foliage and, unlike other species, recovers quickly and well from even hard pruning.

WEEK 22

Pagoda Tree  Sophora japonica

Despite its English and Latin names, the Pagoda Tree, also known as the Scholar Tree, is native to China, and its common name probably comes from the fact that it was often planted in the grounds of Buddhist temples.  It is a strong grower which stands conditions in cities very well.  Its strong wood has been used in the Far East for making pillars and door posts.  It is a deciduous tree, which provides light shade and produces cream-coloured, sweet scented flowers in the summer.  In Gibraltar there are several planted south of Referendum Gates, and one in the Alameda Gardens, although the oldest and most impressive tree of this species is in the north-west corner of the Anglican Holy Trinity Cathedral.  The Scholar Tree is one of which we could see a lot more of in Gibraltar.

WEEK 21

Australian Silk Oak  Grevillea robusta

This is an elegant, potentially very tall tree (up to 30m) from Australia (New South Wales to Queensland), which is becoming increasingly popular in the area as an ornamental.  It grows with a very straight trunk, and has fern-like dark grey-green foliage.  Just about now, in mid May, the tree produces numerous bright golden-orange flowers.  These literally drip with nectar and provide a source of food for insects and birds alike.  The Silk Oak (sometimes known as Silky Oak) is not an oak but a member of the Protea family, which has many representatives in the southern continents.  It can grow well in dry, sandy areas, and inhibits the growth of other plants nearby.  In Australia the wood is used ornamentally for cabinet-work, plywood, panelling and furniture.  The tallest Silk Oak on Gibraltar is in the Alameda Gardens.  Younger trees can be found in the grounds of the Mount, while the trees in the “Piazza” at John Mackintosh Square are of this species.

WEEK 20

Round-leaved Oak Quercus rotundifolia

WEEK 19

Bottlebrushes  Callistemon and Melaleuca

The Bottlebrushes are attractive trees and shrubs from Australia, like so many other plants now grown in the Mediterranean.  Bottlebrushes are generally members of the genus Calistemon, and are very closely related to the paperbark trees, or Melaleucas.  They occur mainly in the east and south-east of Australia, although there are a few western species.  They both are members of the Myrtle family, and many have myrtle-like leaves, although leaf shape varies tremendously between species.  Their flowers resemble bottlebrushes, or powderpuffs and in the best-known species are bright crimson, although they can be white, pink or yellow.  They are increasingly popular as garden plants around Gibraltar, although most have only been brought in over the past few years and there are few mature ones.  Some of the ones in the Alameda Gardens are however quite old, having been planted there several decades ago.

WEEK 18

Osage Orange  Maclura pomifera

This species, also known as the Hedge Apple, is originally from central North America, where as well as growing wild it has been planted widely as a street tree and for hedging.  It was a tree known to the native Americans who prized its branches for making bows.   Its fruit is used traditionally to keep insects and spiders out of houses.  It is a deciduous tree with bright green foliage, and its fruit is externally like an orange, although inside it has a mass of pith – on which animals can choke if they eat them.  In North America, however, the seeds within the pith are a favourite food of squirrels.  There are very few of these trees in Gibraltar, despite the fact that they are attractive and provide goof shade in the summer.  There is one in the Alameda Gardens by the Lions’ pond, and one or two elsewhere in the South District.

WEEK 17

Nettle Tree  Celtis australis

The Nettle Tree (also known as the Mediterranean Hackberry) is one of the most attractive trees in Gibraltar.  They are found in gardens, mainly in the South District, and on the lower parts of the Upper Rock, especially around Engineer Road and in the gardens of the Mount, where they form a natural-looking woodland not found elsewhere in the surrounding area.  It is a deciduous tree, which is now coming into leaf.  Its foliage now looks luminous pale green, although it will go darker later in the summer just before its leaves drop in autumn. The leaves are thought to have medicinal values, especially as an astringent.  It has a very smooth, grey bark and grows up to about 15m.  The dark purple fruit that appear in the autumn are much favoured by birds, and are also edible for humans.  Some of the nettle trees in Gibraltar are several hundred years old, and are among the oldest of our trees. 

WEEK 16

Torrey Pine  Pinus torreyana

The Torrey Pine is the rarest pine in the world.  It occurs only in two widely separated areas in California, on the coast at San Diego and on Santa Rosa Island.  Its population fell to a total of fewer of 9000 in the 1980s.  These clearly ran the risk of obliteration in case of a major fire.  In addition, the pines were all found to be genetically very similar, so that they could all be susceptible to such threats as disease.  The Royal Botanic Garden in Edinburgh collected seed in the wild.  These were sown in 1996 and the pines grown in their greenhouses – until they grew too large.  Thirty were sent over to Gibraltar, where the climate is similar to California’s for growing out of doors.  These are a “reserve population”,  should any harm come to the wild Californian trees.

WEEK 15

Australian Pine  Casuarina equisetifolia

This is a popular tree in the Mediterranean, and is another species that has been introduced from the southern hemisphere, being found wild in Australia, Malaysia, the Philippines and Polynesia.  From even a short distance it looks very much like a pine, because it has small, cone-like fruits and branchlets of scale-like leaves that look like pine needles.  But it is not a pine at all and belongs to its own family, the Casuarinaceae.  It has many other common names, including , coast she-oak, horsetail, whistling pine and beefwood.   Its wood is very strong, resisting decomposition and the effects of salt water, giving it is other name, “ironwood”.  One characteristic of the tree is that its roots fix nitrogen in the soil, a feature normally associated with members of the pea family.

It is an attractive tree, which, although it is considered a pest in some places where it has been introduced, for example Florida, does not threaten natural habitats in Gibraltar.

WEEK 14

Narrow-leaved Ash  Fraxinus angustifolia

The Narrow-leaved Ash is an upright deciduous tree with a broadly oval crown sometimes reaching 10m in height. The trunk is smooth and brown on young trees but becomes grey with ridges and furrowed with age. It flowers in early spring before the leaves sprout, with male maroon flower dense clusters and looser green female flowers. The leaves are shiny, dark green above and lanceolate, 10-15cm long, serrated and tapering. It grows best in damp soils.  It is a native of North Africa and the Iberian Peninsula, but the tree has been introduced to many countries with similar Mediterranean climate.

In Gibraltar it is probably native and is found mainly within the gardens of the Mount and elsewhere in the South District. The species has spread into the surrounding area with many young saplings along Engineer Road at the entrance to the Upper Rock. It is also well represented in the Sandpits area, south of the Botanic Gardens and present also in the Gardens and the Trafalgar Cemetery where a particularly large specimen can be seen.

The species is not under threat but due to its limited distribution could be adversely affected by the development of its main strongholds.

WEEK 13

Sweet Pittosporum  Pittosporum undulatum

This is not a well known tree, and at present there are only a few in Gibraltar, including one by the tennis courts at the junction of Queensway with Europort Road, another at the Alameda Gardens, and one in the gardens of  The Mount.  It is a pity that it is not more widely used, as it is a good street tree.  It is a small tree in cultivation although in the wild it can reach up to 12m in height.  Like many of our cultivated trees, it comes from south-western Australia.  It has rough grey bark and large deep green leaves with a wavy (or “undulating”) edge.  It is a good shade tree and when it is in bloom its small white flowers have a very sweet and pleasant scent.  It flowers in spring and early summer, and the flowers are followed in autumn by orange berries.

WEEK 12

Indian Laurel or Laurel Fig  Ficus microcarpa

This tree is a native of Asia, one of the many members of the fig family.  It is a tree often used on roadsides (like at the south end of Main Street) and that can be shaped by clipping but that, if allowed to grow, that reach a great size.  An example if the fine specimen outside the Cottage in the lower reaches of the Alameda Gardens.  The tree has smooth, grey bark and milky sap, like many figs.  If produces small figs twice a year, which are much liked by birds that will eat both the flesh of the fruit and the seeds.  For pollination figs need a specific type of wasp.  The wasp for the Indian Laurel is not found in Gibraltar, so that most of the seeds are not fertile.  This is just as well, as otherwise the tree would spread widely to the exclusion of native species.  As it is young specimens are occasionally found in different parts of Gibraltar, often growing from cracks in walls and even in gutters, as they need very little soil to grow.

Given that, it is a very attractive tree with dense, dark green shiny foliage – as long as it’s kept under control!

WEEK 11

Acacias Acacia spp.

The Acacias, which include the Mimosa tree, are a large, mainly tropical group closely related to the peas and vetches.  Although widespread in the wild, mainly in Africa and Australia, their range has been extended further as they have been introduced to many other parts of the world, including Gibraltar.  Several species grow here, most of the flowering new, in early spring.  All of our species have bright yellow flowers, with a typical “powder puff” appearance, and the flowers are often profuse and cover the whole tree.  Perhaps the best known here is the Golden Wreath Wattle Acacia saligna, from south-western Australia.  This has long, simple leaf-like phyllodes (modified leaf stalks), although many other species have compound leaves with tiny leaflets.  An example of these is the Sweet Thorn Acacia karoo, which has very long, sharp thorns, of which there is an example at the entrance to the Alameda Gardens.  Attractive as they are, in many parts where they have been introduced they have become pests as they quickly replace native vegetation.  This has in fact happened in Gibraltar where the Golden Wreath Wattle and especially the Rooikrans Acacia saligna are a threat to the native plants of the east side sand slopes.

WEEK 10

Tasmanian Blue Gum  Eucaylptus globulus

The Eucalypts are among the best known of city trees in the Mediterranean, although they originate from Australia.  They do well in our climate, and the fact that they grow fast has made them popular throughout the warmer regions of the world. They have a multitude of uses, which includes the use of young trunks as fence posts and props for the building industry, to their use in paper mills.  They are often grown as single street trees, or in rows on roadsides, but also, for example in Morocco, also in huge plantations.  The problem with Eucalypts is that they can take up a great deal of water and can dry up areas.  They also tend to exclude plants from the undergrowth, and outside Australia there are few insects adapted to feeding on them, which makes them devoid of most wildlife.  For this reason their cultivation is discouraged nowadays in many areas.

In Gibraltar there are two main species, the Red Gum Eucalyptus camaldulensis, and the Tasmanian Blue Gum E. globulus.  The latter, illustrated in the photograph, is the rarer one of the two.  It is a more robust tree with bluish foliage and larger flowers which can give the tree an attractive white appearance when they open.

WEEK 9

Washiongtonias  Washingtonia spp.

These are probably the most used palms for landscaping, especially in Mediterranean regions of the world. The Washingtonia robusta, native to Baja California and Mexico is the tallest of the genus with a much thinner trunk, the leaves are bright green and the leaf tips bends twinkling in the wind . Very fast growing and it is the best suited for landscaping.  
This palm, filmed as background scenes in lots of Hollywood movies, TV series and on post cards from Southern California. Orange sunsets over the Pacific with Washingtonia in the foreground, set a trend for other beach, Mediterranean resorts of the world.

The Washingtonia filifera native to Southern California is less used for landscaping and not as fast growing as the W. robusta. Washingtonia filifera is shorter in height and has a much thicker trunk; the leaves are larger and stiffer and of a grey green colour. In its native habitat around the Mohave desert the old leaves form a petticoat around the trunk protecting the trunk from extreme temperature.

In Gibraltar you will find the Washingtonia robusta at The Alameda Botanic Gardens, some on the south district and upper town area and along Winston Churchill Avenue. There are few Washingtonia filifera left in Gibraltar.  These are a large specimen at the Duke of Kent House gardens and another on the south facing side of Rosia Plaza apartments.

WEEK 8

Ombu or Bellasombra  Phytolacca dioica

The Ombu or Bellasombra is a feature of Gibraltar, with more specimens here than in  most locations in the region.  It is a native of the pampas of South America, being found in Argentina, Brazil and Uruguay.  The trunk can grow to a girth of 15m  and can grow up to 20m in height.  It is a semi-succulent tree, with a spongy, fire resistant trunk, adaptations which make it one of the few trees that can survive in the pampas.  In Gibraltar it is semi-deciduous, usually keeping some leaves throughout the winter, but dropping most if it is too cold.  The tree produces small white flowers, followed by juicy dark purple fruit.  The fruit are used for colouring and are considered edible, while is some places a tea is brewed from the leaves.

In Gibraltar there are quite a few well-grown specimens probably around 200 years old or more.  Sadly there are very few young ones, although some have been incorporated in the last few years into planting schemes in the Europa Point area where some of the best stands of the species locally are found.

WEEK 7

Carob Tree  Ceratonia siliqua

Known in Spain as the “Algarrobo”, the Carob tree is a native of the Mediterranean, known since before biblical times.  In fact, its hard, rounded seeds are believed to be the original basis of the carat.  These seeds are found in large curved pods that arise direct from woody stems.  The pods are bright green at first and then turn brown.  They are sweet to the taste, and are used is chocolate substitute for diabetics, and also as fodder for animals.  The Carob is a member of the pea family.  It has compound leaves with rounded dark green leaflets, and individual plants can be very long lived.  They are a feature of the scrub in many Mediterranean hillsides, although it is quite rare on the Upper Rock, probably due to the cutting down of the vegetation during the sieges.  As its seeds are hard, they are not eaten by birds, and so the plants spreads only slowly.  There are however, some fine examples of Carob trees in the Alameda Gardens, and in the Convent.

WEEK 6

Canary Island Date Palm  Phoenix canariensis

No doubt the best known palm tree in our area, and now widespread in many of the warmer regions of the world, this tree is originally native to the Canary Islands.  It is an attractive palm, which can grow tall with a full head of fronds which, if not cut off, stay on the tree for many years giving the head a rounded appearance.  This palm  produces orange dates which are not edible as they have a bitter taste, but are fed upon by birds and other animals.  The Canary Date Palm grows well in many locations and types of soil, and is even naturalised in some Mediterranean countries.  It is, however, susceptible to diseases, including some fungi, and to the Palm Weevil, a species of beetle that eats through the growing top and kills the tree.  This weevil, native to Asia, is now present in Spain and will no doubt appear soon in Gibraltar, leading to the almost inevitable and very sad death of many of our Canary Date Palms.

WEEK 5

Dragon Tree  Dracaena draco

The Dragon Tree is an unusual tree with a grey bark and grey-green leaves – though woody it is botanically closer to a lily than to most other trees.  It produces white flowers  in summer, followed by bright orange fruit.  Although there are similar trees in Socotra, the species grown in Gibraltar is native to the Altantic islands of Cabo Verde, Maderia and the Canaries.  Here they had great medicinal significance to the native Guanches.  The Phoenicians, who visited the islands in the 8th Century used the sap as a dye.  Once the sap exudes from the damaged trunk it forms a red crystalline substance, known as dragon’s blood. 

Dragon trees branch every fifteen years or so after they flower, giving the tree their regular branching appearance.  The photograph is of the oldest Dragon Tree in the Alameda Gardens, which is probably about 300 years old

In 1994 a population of wild dragon trees was discovered in mountains in central Morocco – the first evidence that the tree is native there.  This Moroccan variety, Dracaena draco ajgal, is more similar to the trees in the Alameda than the Canary Island ones, which have thicker trunks and branch nearer the base.

WEEK 4

Oleander Nerium oleander

Usually considered a shrub, the Oleander, known in Spanish as Adelfa, will, if allowed to do so, grow into a small tree.  It is a native of the Mediterranean, where it usually grows along river banks and around other wet areas, preferring never to be too far from water.  Indeed, it is often by seeing a winding row of oleanders that rivers beds can be located in dry areas.  It does, however, grow well in cultivation, as often in these situations they will be watered.  In Spain, for example, they are often planted in the central areas of motorways, and in Gibraltar they are grown in many planted areas, for example along Red Sands Road.

The wild form of the Oleander has pink flowers, but many cultivated varieties exist, including white and red-flowered and double-flowered forms.  Because they flower in summer – June, July and even August, they often brighten up areas which can be dull during the Mediterranean summer drought.

WEEK 3

Wild Olive Olea europea

The wild Olive is probably the commonest tree in Gibraltar, making up most of the scrub of the Upper Rock.  It is also the commonest in the Alameda Gardens, with over 40 specimens.  Although common it is a very important tree to preserve.  Mature olives give character to much of the South District of Gibraltar, and its small black fruit provide food for many migrating and wintering birds from northern Europe

Its leaves are tough and shiny above and greyish below.  It has small white flowers which are out in May and can carpet the ground when they fall in good years.  It has a good hard wood traditionally used for carving around the Mediterranean.

The cultivated varieties of the olive are well known for their edible fruit, often converted to Olive Oil.

WEEK 2

Stone Pine Pinus pinea

The Stone Pine is the most common pine tree on the Rock.  It is one of the main trees of the Botanic Gardens at the Alameda where in the best specimens its umbrella shape is clearly visible, and the reason for its alternative name, “Umbrella Pine”.   It can also be distinguished by the large plates formed by the reddish-brown bark.  Its cones have large edible pine nuts – known as piñones – which are popular sugared at Christmas time and are also used in cooking.  It is these large, hard, stone-like seeds that give this pine its name.

Stone pines are also found on the Upper Rock where they were planted in the early years of the 20th Century to provide shade for the troops. Many of those on the Upper Rock died during the drought of 1994-1995.

In the Alameda, the pines were planted in the early years of the Gardens and many of them are about 200 years old.  Tree management in recent years has included work by tree experts from the Royal Botanic Gardens, Kew, which should help in extending the like of these old giants.  More pines of this and other species are now being planted, to eventually replace the older ones when they finally have to go.

WEEK 1

Kusamaki, or Broad-leaved Podocarp Podocarpus macrophyllus

This is one of the most attractive trees in Gibraltar.  It is located on the east side of Grand Parade, overlooking the car park, at the very edge of the Alameda Gardens.  One of the surprising things about this species is that,like the pines and the firs,  it is a conifer, but its leaves are broad and not needle-like. The Kusamaki is a native of Japan and China, and this specimen, probably close on 200 years old, is the only mature one in the region.  a sapling, originally a cutting from this tree, was planted in the grounds of the Mount by Princess Anne during her last visit to Gibraltar.   It is a tree with a very full foliage and particularly attractive bright green new growth.