Hi welcome to Taiga Bonzai, we continue our journey through the alphabet starting with the letter ‘R’.

Introduction – all trees and shrubs have some form of defence, some highly toxic and dangerous to domestic animals and humans. Whilst others are not considered harmful. Yet some whom work with these plants do not take adequate precautions, hence with negative results.

Rhododendron – Spp. family Ericaceae. Contains approximately 1,024 species of trees and shrubs. Both evergreen and deciduous and found throughout the world, from north America, Europe and Asia. They are a common addition to any bonsai collection, due to their colourful showy flowers that bloom from late spring to early summer.

All Rhododendron species including, Rhododendron obtusum, Rhododendron simsii, Rhododendron indicum and Rhododendron luteum are poisonous. They contain Andromedotoxins that are water-soluble diterpenoid compounds in the leaves flowers and nectar.

If any part of the plant is ingested symptoms include, salivation, a burning sensation in the mouth, emesis, diarrhoea, muscular weakness, impaired vision and dyspnea. Hypotension and atrioventricular block, a serious cardiovascular effect that may have fatal results.

Rosary Pea – Abrus precatorius. family Fabaceae. Known by other names including the ‘Jequirity bean’ is native to warm and tropical regions and also found in bonsai. Those with children and domestic pets are advised not to keep such a plant due to its very nature.

This species with its frond-like leaf formation and bright red fruit is extremely poisonous as it contains the toxin abrin. This is similar in structure to ricin the toxin in Ricinus communis or ‘Castor bean’ plant and some claim that abrin has a higher toxicity level. Abrin is found in all parts of the plant but, it is the seeds that attract the most attention and if crushed, chewed and ingested abrin is released and can be fatal.

Rowan – Sorbus aucuparia. family Rosaceae. Native to the northern hemisphere are also found in more temperate climes including Africa and Asia. Its growth can be prolific portraying grey bark, compound frond-like leaves and scented flowers white to cream with orange to red berries.

This combination makes the species very attractive to bonsai collectors. Nonetheless, rowan tree berries are poisonous as they contain parasorbic acid, which is used as a food preservative and in cosmetics. Symptoms can include, eye and respiratory problems, skin irritation and abdominal pain. However, if they are cooked the parasorbic acid is transformed into sorbic acid, which is not poisonous if ingested.

Snowberry – Symphoricarpos alba family Caprifoliaceae. Also know as the ‘ghost berry’ and ‘wax berry’, a genus of approximately 15 species native to north America are found in other parts of the world.

They are members of the honeysuckle family Caprifoliaceae used in bonsai for their fragrance and decorative flowers and coloured fruit, white, pink and red depending on the species.

The white berries of Symphoricarpos contain the following toxins, viburnin, chelidonine, saponins, tannins, terpenes, tryglycerides and coumarins. If ingested the symptoms are vomiting, blood in urine and delirium. However, the toxic combination has a powerful emetic effect – a gastrointestinal irritant, which causes the victim to expel the berries undigested.

Spindle tree – Euonymus europaeus. family Celastraceae. A native to Europe is a deciduous tree or shrub noted for its colour changes during the season. It has leaves that change from dark green to yellow to red to purple and flowers yellow to green grown in clusters.

The fruit, which can be pink, red or purple when ripe open to reveal its orange coloured seeds. This colour change make it a popular specimen for bonsai. However, the fruits are poisonous, a cocktail of toxins including, alkaloids theobromine, caffeine and terpene. Poisoning in children is quite common as the brightly coloured fruits are attractive. Ingesting the fruit can cause liver and kidney damage and can be fatal.

Spurges – Euphorbia Spp. family Euphorbiaceae. A genus with over 500 species of trees and shrubs including Euphorbia tirucalli, a tall growing shrub native to semi-arid tropical climates. It has a wide distribution throughout Africa and is common in the dry states of north America in particular California.

In bonsai E.tirucalli is not one of the most favoured of specimens although it can be found, because of the problems of shaping and pruning. For example, merely cutting a branch or twig causes the plant to ooze a sticky white toxic latex.

This latex when in contact with skin is extremely irritating causing redness and a burning sensation. If in contact with the eyes the result is severe pain and temporary blindness. If ingested symptoms are burning to the mouth, lips and tongue and can be fatal.

 Tamarac – Larix laricina. family Pinaceae. Known as the black, eastern, red and American larch, is native to north America and Canada. This species is both coniferous and deciduous due to its needle leaf structure that is shed in the autumn.

The Tamarac has more medicinal qualities as opposed to toxicity for example. Tea made from the bark was used as a laxative, a remedy for rheumatism and skin ailments.

However, this species is prone to attack from the fungal pathogens including Lachnellula willkommii and contact with it should be avoided. It is also argued that oil from the leaves in contact with the skin can cause dermatitis nonetheless, it is a popular species found in many a collection.

Titoki – Alectryon excelsus. family Sapindaceae. Formerly known as the New Zealand oak is as its name suggests native to this antipodean realm. Like its European counterparts it has a twisted trunk with branches radiating in all directions and its apex is formed into a canopy.

Its flowers are relatively small and purple in colour and it’s fruit are a pink to grey capsule that when ripe, open up to reveal a bright red pulp with a black seed. The Titoki seen in some bonsai collections is poisonous, it contains tannins and cyanide producing poisons in the bark, leaves and fruit. If ingested can cause; vomiting, gastroenteritis, diarrhoea, delirium, kidney failure and at worse fatality.

Tea tree (Chinese) – Camellia sinensis family Theaceae. This is an evergreen shrub that if left to its own devices can grow in access of 5 metres (16ft) in height. Producing white flowers with bright yellow stamens surrounded by glossy green leaves and fruit having a hard green shell and a single brown seed contained within.

There are many cultivars of the tea tree that are used to make a refreshing beverage partaken by countless individuals including, the Camellia sinensis assamica (Assam, India) strain. Nonetheless, the tea tree is considered poisonous because it contains caffeine and tannin toxins that are addictive.

It is argued that consuming five cups a day are sufficient to produce addiction and reduced intake or withdrawal. Causing; dizziness, headaches, palpitations, indigestion, constipation and insomnia. Moreover, excessive intake or over indulgence can be harmful to pregnant women.

In the next article on this subject ‘toxicity’ we continue with the letter ‘U’, until next time, BW, Nik.

Hi, welcome to Taiga Bonzai, we have written articles on a selection of pests and disease recently. As a result our followers (horticulturists and bonsai enthusiasts) have asked for further research on this subject.

Introduction – in the last article we concluded our discussion on the ‘Toxicity’ of various shrubs and trees and their potential to be mildly irritant to being potentially fatal. However, all flora regardless of their ability to defend themselves are prone to attack from pests and disease. This increasing problem creating havoc on the world’s horticulture production and effect on society, is not a new phenomenon; it is the result of mankind’s actions.

Since the dawn of time – mankind’s actions have caused catastrophic consequences in many ways, the world is facing unprecedented challenges that will be extremely difficult to resolve. Have we reached the point of no return? Some believe that we have past it, others are more complacent, ‘These situations need to be addressed but they can be resolved’.

During our travels around the globe we have been privy to some extraordinary and amazing locations, returning to them at a later date we note that many have been destroyed. Piles of rubble, barren land, some are now heavily polluted – rife with pestilence and disease. Such experiences do not wane, they remain strong and clear in the mind. How have we arrived at this juncture? Follow our journey as we try to shed some light on the issue.

The beginning – according to scientific research vegetation had evolved on Earth approximately 700 million years ago with fungi and bacteria approximately 1,300 million years prior. This evidence is based on the earliest fossils of those organisms. The general consensus is that organisms also called microbes are beneficial for example, they keep nature clean by helping break down dead plants and animals into organic matter.

Mankind’s contribution – the hunter-gatherer culture developed among the early hominins of Africa, with evidence of their activities dating as far back as 2 million years. According to Richard B. Lee & Richard Daly (Cambridge Encyclopedia: Hunters and Gatherers) “Was humanity’s first and most successful adaptation, occupying at least 90 percent of human history“.

In addition, it is understood that through archaeology, anthropology, genetics, linguistics and the advent of writing from primary and secondary sources, this information is relatively common knowledge.

Colin Tudge in his book ‘Neanderthals, Bandits and Farmers: How Agriculture Really Began’. New Haven, CT: Yale University Press (1998) contends that “The Neolithic saw the Agricultural Revolution begin between 10,000 and 5000 BC in the Near East Fertile Crescent” (Mesopotamia). During this period humans began the systematic husbandry of plants and animals and agriculture advanced.

Many humans transitioned from nomadic to a settled life style as farmers in permanent settlements. The relative security and increased productivity provided by farming allowed communities to expand into increasingly larger units, fostered by advances in transportation.

However, Alina Polianskaya of ‘ Inews.co.uk‘ (March 15th 2018) points out that “Early humans may have been trading with each other much earlier than previously thought. Scientists excavated ancient artefacts at Middle Stone Age sites dating back 300,000 years at the Olorgesailie Basin, in southern Kenya. They uncovered weapons made of materials that could not be found there, suggesting hominins at the time may have exchanged goods with others.”

In his paper ‘Evolution: What Makes a Modern Human’ Nature. 485 (7396) (2012) Chris Stringer tells us that “Modern humans spread rapidly from Africa into the frost-free zones of Europe and Asia around 60,000 years ago.” This notion is supported by Adam Hart-Davis in his work ‘History: The Definitive Visual Guide’. New York: DK Publishing.

He contends that “The rapid expansion of humankind to North America and Oceania took place at the climax of the most recent ice age. At the time, temperate regions of today were extremely inhospitable. Yet, by the end of the Ice Age, some 12,000 years ago, humans had colonised nearly all ice-free parts of the globe“.

The Silk Road – a network of trade routes connecting China and Far East with the Middle East and Europe, was established when the Han Dynasty in China officially opened trade with the West in 130 BC. Although these Silk Road routes were protected from exterior forces by the Han and other countries under signed treaties, pests and disease also travelled with the traders.

This lead to infection, sickness and often death, because those who came into contact with these infectious bacteria had no immunity for example. October 12, 1492, the day when Christopher Columbus landed on the island of Guanahaní (San Salvador now part of the Bahamas.) The beginning of what was yet to come.

The Silk Road routes remained in use until 1453 AD, when the Ottoman Empire boycotted trade with China and closed them. It has been nearly 600 years since the Silk Road was used for international trade, but the routes have had a lasting impact on commerce, culture and history that resonates today and are being reopened.

International trade is arguably the most important factor in the modern world, as nations rely on others to supply the many types of commerce they need. Agreements are signed to lessen the bureaucracy nonetheless, international trade does bring problems as we shall find out in this series.

Yet some countries enforce stringent rules on imports for example, Australia probably has the strictest regulations on what is imported. Meat products, fruit and plant material including seeds from many countries including Asia and Middle East are prohibited.

However, some are permitted if the exporter is registered and has the required documentation. Unlike the rest of the world Australia (although having its own disease problems) is free of many other known diseases and has been since 1872, due to stringent pre and post-border measures. Meanwhile the rest of the world continues to battle with disease containment.

Today much has changed, we have advanced – science and technical horticultural knowledge has allowed us to become adept in food production. New plant species have been introduced, more variety and apparently more taste – but have we gone too far?

The reason why this question is asked is because for every action there is a reaction often resulting in irreversible consequences. Now pests and disease endemic to a particular part of the world are now commonplace in many other regions where flora has no defence.

How this phenomenon occurred is partly due to the fact that pests and disease are able to migrate via wind and wing over vast areas for example. The locust derived from the Latin locusta, in the family Acrididae a swarming insect that devastates vast areas of crop land is able to fly up to 2000 metres covering 200km per day.

Between June 2019 and February 2022, a major outbreak of desert locusts began developing, threatening food supplies in East Africa, the Arabian Peninsula and the Indian subcontinent. The outbreak was the worst to hit Kenya in 70 years, and the worst in 25 years for Ethiopia, Somalia, and India.

However, pests and disease are transmitted by other means including packaging, cross contamination, from animals, by dust suspended in the air and by food and water. But in the main it is the consequence of our actions, for which mankind is ultimately responsible. In the next article of ‘Unseen invasion’ we look at some examples of this, until next time, BW, Nik.