Notable trees

Jacaranda mimosifolia

Also known as the fern tree, the graceful and spectacular jacaranda is a native of Bolivia, Argentina and Brazil, and one of their most beautiful exports. In Sydney, Perth, Pretoria, Lisbon, and in Pakistan and the Caribbean jacarandas lift the spirits; planted with gay abandon they create an amethyst canopy of fragrant flowers over suburban streets, and lay a purple carpet beneath, while the delicate emergent foliage castes a welcome summer shade. A great investment as a street tree not only for their beauty but also their contribution to air cleaning, urban cooling, and community mental health. 

Jacaranda is a member of the bignonia family, which includes catalpa and paulonia. Grown in well-drained soil in full sun and frost free, it can reach 20 metres in height. It is deciduous, and may bloom twice a year. Despite the beauty of its flowers all parts of the tree are poisonous, ‘causing vomiting, diarrhoea, irregular heart beat, dilated pupils, coma and death’. The pale wood, when still green, is used for turnery and bowl making. Extracts of jacaranda also have antimicrobial properties against E. coli and Staphylococcus aureus.

In folklore the jacaranda is associated with wisdom, rebirth, wealth and good luck. If its flower falls on your head it is thought to bring good fortune. In Queensland late spring is known as the ‘Purple panic’, the time when the jacaranda flowers and students are stressed out completing assignments and preparing for final exams. However in Pretoria it is said that if the flowers fall on your head it means you will pass your exams!

New South Wales Christmas Bush (Ceratopetalum gummiferum)

Growing in a garden in Hamilton Road, this small tree had me mystified. Tolerant of -2 degrees of frost, it is a native of Papua New Guinea and eastern Australia, where it grows to 12 metres in height – so not really a bush. It is usually found growing in sandstone or old sand dunes, as it enjoys a well-drained soil. It was first described to the western world by the English botanist, James Edward Smith in A Specimen of the Botany of New Holland (1793). The leaves are tri-foliate, each leaflet being about 5-8 cm long and 0.5 cm wide. In late spring it is covered in sprays of tiny, white, five-petalled flowers (some of which can be seen in the photo), but these often go unnoticed until they begin to die and the sepals then enlarge and become pink in colour. This display peaks at Christmas in Australia, perhaps a little later in New Zealand. These pink sprays will last in water for weeks.

 The leaves contain aesculin, a coumarin glucoside (also found in certain chestnut trees) which is sometimes used in the treatment of lupus, and also as an ultra-violet radiation screen in suntan lotion. It is used as a fragrance in some skin care and bath products, with a scent reminiscent of freshly-mown hay.

Fraxinus angustifolia is a deciduous Tree growing to 25 m (82ft) by 12 m (39ft).

It is hardy to zone (UK) 6 and is not frost tender. It is in flower from April to May. The species is hermaphrodite (has both male and female organs) and is pollinated by Wind.

Suitable for: light (sandy), medium (loamy) and heavy (clay) soils. Suitable pH: acid, neutral and basic (alkaline) soils and can grow in very alkaline soils. It cannot grow in the shade. It prefers dry or moist soil. The plant can tolerates strong winds but not maritime exposure. It can tolerate atmospheric pollution.

Kauri (Agathis australis) provides an impressive sense of scale in this Maungakawa garden.

Members of the Araucariaceae family (think monkey puzzle and Norfolk pine), kauri have an incredibly ancient lineage of hundreds of millions of years. The growth rings of fossilised trees preserved in Northland bogs provide scientists with thousands of years of detailed climatic history, allowing analysis of annual changes in atmospheric humidity, vapour pressure and carbon.

Kauri has been valued both for its timber and its resin. Maori harvested it for prestige items such as grand waka, while the British navy valued the tall straight trunks as masts; it is said that when Lord Nelson defeated Napoleon at the Battle of Trafalgar, his ship was fitted with kauri masts. Many of our oldest historic buildings are made of kauri. The resin was used by Maori as a fire-starter and making torches for night fishing; the resulting soot was then mixed with oils for tattooing. Europeans used Kauri gum to make varnish, and in the latter half of the nineteenth century it was a more valuable export than timber, wool or gold.

Some Northern Maori thought of the kauri as the legs of Tāne Mahuta, holding sky and earth apart. In other traditions this giant of the forest is connected to the giant of the ocean, the sperm whale, parāoa, both sons of Tāne Mahuta. When Parāoa failed to persuade Kauri to join him in the ocean, he suggested that they swap skins, saying, ‘One day men will cut you down and make you into waka, and with my skin you will be able to withstand the salty seas.’ This explains why the bark of kauri is thin and oozes resin like the ambergris of the sperm whale. (Vennell, Meaning of Trees)

Blue Atlas Cedar (Cedrus atlantica glauca)

The name cedar is often used for any tree with dark, spicy-scented wood. In Japan there is the plume cedar (Cryptomeria), in North America the incense cedar (Calocedrus), Western cedar (Thuja) and Eastern cedar (Chaemocyparis). But the true cedars, distinguished by their majestic architecture, are only four in number and three of these are found around the Mediterranean. Similar in appearance to the cedars of Lebanon, Cedrus atlantica is a native of the Atlas Mountains of Morocco, tolerating hot dry conditions. Global warming has prompted a search for forest species that will thrive in central Europe and indications are that the Atlas cedar may be most suitable. Its blue form remains a popular garden tree, though not really suitable for a small space due to its colossal spread when mature. Hugh Johnson describes seeing ‘their desperate pale-blue gestures over every little garden wall in some parts of France’.

I remember fondly the blue cedar that grew in the admittedly-large garden of my childhood. At Christmas we decorated it head to foot with handmade streamers, stars and bells, but by the time I arrived at adulthood it was almost out of reach, so only a few of the lower branches could be festooned with tinsel and baubles. Nowadays at 45m high its days as a Christmas tree are over.

The wood of the Atlantic cedar is pale brown with well-defined growth rings. It is durable and notable for its resistance to fungi and termites, but because it tends to distort when drying and may be brittle, it is not particularly good for building. However it is easy to work and takes a fine finish, so is popular for joinery, furniture and veneer.

Weeping Willow (Salix babylonica and various cultivars)

Like the daffodil, the willow is a harbinger of spring. There are 450 species of willow, which are widespread across Europe. Since prehistoric times the long stems from pollarded willow have been used for weaving baskets, boat frames, fences and fish traps. The trees are used in Holland and Belgium as boundary markers, and as such often feature in the paintings of Rembrandt and van Gogh.

The weeping willow, although usually associated with water, actually originated from the dry northern regions of China. Cultivated for millennia in Asia, it spread along the Silk Road to Europe, and was introduced to England in 1730 from Aleppo in Syria. In 1736 it was named by the famous botanical taxonomist, Carl Linnaeus, who thought it was the tree referred to in the Bible, Psalm 137:

‘By the rivers of Babylon, there we sat down and wept when we remembered Zion; We hanged our harps upon the Willow in the midst thereof.’

In fact the trees of Babylon that grew along the Euphrates River were not willows but a ‘weeping’ poplar.

Despite this error the association remains between willows and sadness. In Europe in the Middle Ages a willow wreath indicated that the wearer was in mourning. Such gloomy connotations gradually also came to signify a lover’s rejection, and today in modern Dutch ‘to hang one’s cigarettes upon a willow’ means to give up smoking! In fact far from being the signifier of sorrow, the willow has been known since ancient times as an agent for the relief of pain and fever; in 400 BC Hippocrates prescribed willow bark for rheumatism. The bark contains salicin which is the drug used in modern aspirin tablets.