Article 25 – ‘Toxic Bonsai Part IV’

Toxic Bonsai Part IV

Umbrella tree (Queensland)Schefflera actinophylla. Family Araliaceae. Is an evergreen tree that grows to 15m (49ft) tall, native to the tropical rain forests of New Guinea, Java and Australia’s eastern Queensland. This decorative tree when mature, produces racemes up to 2m (6.5ft) long with an abundance of small dull red flowers beginning in late spring. Schefflera actinophylla is considered to be an aggressive plant prolific in growth, hence the reason why it is an uncommon specimen in bonsai collections. Schefflera actinophylla does contain toxins, but these are not considered to be dangerous to humans. Ingesting the leaves can cause mouth tingling and numbness, vomiting and abdominal pain and sap when in contact with skin can cause irritation and rash.

Umbrella treeSchefflera arboricola. (syn. Heptapleurum arboricolum) also a member of the Araliaceae family is native to Taiwan, but can be found world-wide as a house plant and also in bonsai. S. arboricola should not be mistaken for S. actinophylla, because of the height difference. Moreover, S. arboricola has different leaf colour and patterns some variegated with cream to white flowers with yellow edges or centres although much depends on the individual cultivar. S. arboricola is poisonous and carries the same toxins as S. actinophylla and leaf consumption can cause mouth tingling and numbness, vomiting and abdominal pain and sap when in contact with skin can cause irritation and rash.

ViburnumLantana. Family Adoxaceae. Also known as the ‘wayfaring tree’ is a deciduous shrub native to Europe, but can be found in Asia and northern Africa and is a relatively common specimen in bonsai. Its oval dark green leaves have a downy or hair like covering on the underside and flowers that are creamy white in colour and green fruit, which ripen to a bright red eventually turning black when mature. The berries if consumed although mildly toxic can cause vomiting, diarrhoea and abdominal pain if ingested in large quantities.

ViburnumOpulus. Family Adoxaceae. Is often referred to by its common name the ‘Guelder rose’ and is native to Europe, northern Africa and central Asia. This deciduous shrub has three lobed leaves that are opposite to each other having an appearance similar to maples. The flowers in clusters are white in colour with their centre being fertile surrounded by an infertile ring that are produced in early summer and fruit that is bright red. The berries if consumed although mildly toxic can cause vomiting, diarrhoea and abdominal pain if ingested in large quantities.

Virginia creeperParthenocissus quinquefolia. Family Vitaceae. Is native to north America, Canada, Mexico, Guatemala and Europe. It is a prolific deciduous climbing vine reaching heights of over 30m (100ft) and attaches itself to smooth surfaces by small adhesive pads. This plant normally seen growing on the sides of buildings has striking colours throughout the seasons, the leaves change from various greens to yellow to orange to red and purple and this colour change makes the species attractive to bonsai. The flowers are small and greenish white in colour, which change into purple/black berries in the autumn. The sap, leaves and berries are poisonous because they contain the toxin oxalic acid, prolonged skin contact can be dangerous and ingesting any part even small amounts can cause kidney damage and death to humans.

White cedarSpp. Family Cupressaceae. Include Chamaecyparis thyoides – Atlantic white cypress, Cupressus lusitanica – Mexican white cedar, Thuja occidentalis – Northern white cedar, Thuja plicata – western red cedar and Cryptomeria japonica – Japanese cedar. Cedars are conifers and are found in many parts of the world, from northern climes to temperate zones. They have many uses for example, grown as barriers, wind breaks, dense hedging in parks and gardens and are a common species in bonsai. However, all cedars carry toxins the primary irritant being plicatic acid and some are more potent than others for example, the western red cedar and Japanese cedar have the highest content. Exposure to plicatic acid can cause severe asthma, rhinitis or conjunctivitis, that can be progressive. In addition, plicatic acid in contact with skin can cause a hypersensitivity reaction, a type of response seen in tuberculin skin tests.

WillowSalix alba. Family Salicaceae. Is a species native to Europe but is also found in western and central Asia and within this genus are: Salix alba Vitellina – a willow with yellow shoots and Salix alba var. Britzensis, Cardinal and Chermesina having orange to red shoots. The willow a medium sized deciduous tree can be in a weeping form or with a dome shaped crown with long thin leaves pointed at the end. (5–10cm long x 0.5–1.5cm wide) It is often found in bonsai in designs that include slanting (Shakan) and (Fukinagashi) wind swept. Male and female trees each produce their own flowers in the form of catkins that appear in the spring and when mature are wind pollinated. However, the willow contain salicylate toxins in the bark that if ingested can cause the following. Ulcers, nausea, vomiting, stomach bleeding, kidney inflammation, tinnitus and skin rash.

WisteriaSpp. Family Fabaceae. Includes various species of climbing bines (Plants that climb by their shoots) Wisteria brachybotrys, Wisteria brevidentata, Wisteria floribunda, Wisteria frutescens, Wisteria macrostachya, Wisteria sinesis, Wisteria venusta and Wisteria villosa. That are predominantly native to the eastern north America, China, Japan and Korea. Although these species are found in bonsai, arguably the most common is the Wisteria sinesis that when in bloom has a striking floral display for example. The great wisteria at the Ashikaga flower park in Tochigi, Japan, which covers more than 1,990 square meters over half an acre. Wisteria flowers are between 10 to 80cm in length and produced in pendulous racemes and are either purple, violet, pink or white. All parts of the wisteria are poisonous they contain the toxin saponin and if ingested the symptoms are: nausea, vomiting, abdominal pain, diarrhoea, severe gastroenteritis, dizziness, confusion, speech problems and collapse.

Xanthorhizasimplicissima. Family Ranunculaceae. The only member of the genus Xanthorhiza, is native to the eastern states of north America. In the wild this shrub grows in sandy soil to a height of approximately 90cm. Its leaves are in a spiral configuration up to 18cm in length with flowers (6 to 20cm) that are produced in star shaped forms of reddish brown to purple. This attractive plant although used for ground cover in gardens, is uncommon in bonsai as its main stem does not produce a large girth. Xanthorhiza is poisonous, its contain the toxin berberine, which can cause nausea, dyspnoea, diarrhoea, nephritis, urinary tract disorders, skin and eye irritation.

Xanthocerassorbifolium. Family Sapindaceae. Native to northern China is a flowering and fruiting species of small tree growing to approximately 8m and can be seen in bonsai collections although uncommon. Its mid-green leaves 12–30cm in length are pinnate with flowers 10–20cm long containing 5 white petals arranged in panicle form, that appear in spring. The fruit a leathery pod splits open in three sections when ripe to reveal the black seeds, which resemble a small horse chestnut seed. Originally the flowers, leaves and fruits were eaten raw with little or no side effects evident. Nonetheless, it would be prudent for those with sensitive digestive systems to cook them before consumption.

YewTaxus Spp. Family Taxaceae. Yews are widely used in landscaping, ornamental horticulture and bonsai in which over 400 cultivars have been created including. The Japanese yew Taxus cuspidata, Pacific yew Taxus brevifolia and Canadian yew Taxus canadensis. All derived from the European yew Taxus baccata considered as Europe’s oldest living tree of which, a specimen can be found in St Cynog’s church yard in Wales dated to approximately 5000 years. The yew majestic and sombre in its appearance has a reputation as a harbinger of bad tidings for example. The yew tree often found in church graveyards as a symbol of sadness was also made into longbows, a weapon used in the battle of Agincourt 1415 by the English in their defeat of the French cavalry.

Yews are relatively slow-growing and can reach heights of 20m (66ft), with a trunk girth averaging 5m. (16ft) The bark is reddish brown with lanceolate, flat dark-green leaves positioned in a frond-like form on the stem. The fruit consists of a bright red cone called an Aril in which a single seed is contained, these are subsequently consumed by birds who disperse them via their digestive system.

All parts of the yew with the exception of the Aril are highly poisonous to humans as they contain the toxin taxane, that can cause the following if ingested. Low blood counts, arthralgias and myalgias, pain in the joints and muscles, peripheral neuropathy – numbness and tingling of the hands and feet. Hair loss, mouth sores, nausea, vomiting, diarrhoea and in some cases the results can be fatal. Moreover, male and monoecious yews in this genus release extremely small cytotoxic pollen, causing headaches, lethargy, aching joints, itching, and skin rashes and asthma.

Zanthoxylum – Kauaense. Family Rutaceae. Is a genus containing approximately 250 species of coniferous and deciduous trees and shrubs, indigenous to temperate and sub-tropical regions. It is known as the ‘prickly ash’ and is a common species in bonsai. The bark has limpet shaped protrusions containing sharp thorns at the centre, its bright green leaves are oval to oblong in shape with 6 to 8 in pairs on a single stem. The fruit are dull red berries tightly arranged in a cluster, that when ripe are used to make the spice Sichuan pepper. According to Asian herbal remedies, the bark was extensively used as a remedy for rheumatism, toothache and colic. Zanthoxylum is not considered poisonous to humans, but it does have the toxin Sesamin, which can cause digestive issues including, nausea, diarrhoea and abdominal pain. Other symptoms may include Anaphylaxis, an extreme case of allergy caused by Sesamin. All edible parts of the tree must be properly prepared prior to ingestion.

ZelkovaSerrata Spp. Family Ulmaceae. Often know as the Japanese or Chinese elm has two varieties, Japan and mainland eastern Asia Zelkova serrata var. serrata, and in Taiwan Zelkova serrata var. Tarokoensis. Z. serrata is a deciduous tree that in the wild can reach a height in excess of 30m (100ft +) and is favoured for its ornamental characteristics. A short fat trunk from which many branches radiate in a typical broom style. (Hokidachi) Its leaves are round to oblong in different shades of green, (Depending on the species) that change through the seasons to yellows, oranges and reds. The flowers in clusters are yellowish-green, which turn brown as they mature. Z. serrata a popular species is regularly found in bonsai collections. Z. serrata has in the past been used for herbal remedies including stabilising the womb during child birth nonetheless, it would be prudent to seek advice before ingesting parts of this species.

The trees and shrubs mentioned in this list are all toxic to some degree for example. In the beginning of the article part I information was given on the Acacia, a native of the African savanna, that have an abundance of thorns for protection. They also use poison in their leaves as a second line of defence against predation, predominantly from browsing wildlife.

Flora once indigenous to specific climate zones are now common place throughout the world in parks, gardens and bonsai, due to their discovery and availability. These species cultivated for their fruit and flowers and other various uses, all have some form of defence. Their toxicity ranges from mild, meaning having little effect on humans and domestic pets, to being potentially fatal.

As to a particular species’ poisonous capabilities we are basically unconcerned, probably due to its benign appearance or attractiveness and addition to a bonsai collection. Nonetheless, this article was written in order to shed some light on floral toxicity and the potential hazards that exist. But it does not mean we should take to wearing protective apparel. Even the most toxic of bonsai specimens, the Yew – Taxus can be handled, providing we refrain from ingesting any part of it and ensuring that any body part in contact, predominantly the hands and the tools we use are thoroughly cleaned.
Until next time BW, N.


Article 24 – ‘Toxic Bonsai III’

Toxic Bonsai Part III

NandinaNandina domestica. Family Berberidaceae. A common colourful species used in bonsai is not a bamboo plant as it is often referred to, but an evergreen shrub growing to 2m (7ft) tall by 1.5 m (5ft) in width. In springtime new leaves are a bright pink, which turn a glossy green. The flowers are white and in clusters, with fruit in the form of a bright red berry. All parts of this tree are poisonous as it contains compounds that produce hydrogen cyanide, which could be potentially fatal if ingested. Although there are those who claim the tree is non-toxic to humans, ascertaining if there is any truth to the argument is not worth the risk.

NeeaNeea buxifolia. Family Nyctaginaceae. Often referred to as the flowering tropical boxwood, this tree is a native of Puerto Rico. It is a rather twiggy specimen with a large diameter trunk with small long narrow oblong leaves, with new shoots appearing in dark red, flowers and red fruit. No part of this tree should be ingested as it belongs to the Nyctaginaceae family, in which many members such as the Bougainvillaea another favourite in bonsai are poisonous. Symptoms are similar to that of poison ivy and may include, pain, itching or burning skin, blisters and dermatitis.

NutmegMyristica fragrans. Although uncommon in western bonsai collections, can be found in more temperate climes. The problem with Nutmeg seed propagation is that there is no way of knowing once germination has taken place if the plant is male or female. Because this species is dioecious and male trees are unproductive, the common way if one desires a female fruiting tree is to either graft, patch bud or air layer. The Nutmeg although widely use for culinary uses contains the toxin myristicin, a monoamine oxidase inhibitor and psychoactive substance. If ingested in large quantities can induce convulsions, palpitations, nausea, dehydration, and generalized body pain.

OakQuercus. Family Fagaceae. A deciduous and evergreen tree with a variety of species that include, white oak Quercus alba and stone oak Lithocarpus. Oak leaves and acorns are poisonous as they contain tannic acid, which can cause kidney damage, gastroenteritis and diarrhoea in livestock for example. Sheep, goats, horses and cattle, but it has little effect on the domestic pig. It is said humans are not affected providing the tannins have been removed nonetheless, those with sensitive digestion systems should avoid consumption.

OleanderNerium. Family Apocynaceae. A small tree or shrub having approximately 400 different varieties in the genus Nerium can be found in many temperate zones throughout the world. It is widely cultivated as an ornamental plant for parks and gardens reaching heights of 2 to 6.5m. (19ft) Although there now exist many dwarf varieties, which only grow to 26cm (10 ins) and these can be found in some bonsai collections. Oleander when mature has grey bark, with dark green thick leaves arranged in pairs that are relatively narrow in shape. The flowers from white to pink to red are highly scented although much depends on the variety and fruit in a long pod, which when ripe open to reveal large amounts of seed. Oleander although a very attractive plant, is considered extremely poisonous as it contains the toxins oleandrin and oleanrigenin that are referred to as cardiac glycosides. Ingesting any part of an Oleander can cause serious gastrointestinal problems; nausea, vomiting, excess salivation, abdominal pain and diarrhoea. Other reactions to Oleander glycosides include cardiac and central nervous system effects; an irregular or erratic heart rate and drowsiness, muscle tremors, seizures and collapse that can have fatal consequences.

OliveOlea europaea. Family Oleaceae. Olive trees are not toxic and ingesting the fruit has no known side effects. However, olive tree pollen is extremely allergenic and according to the Ogren Plant Allergy Scale, a rating system for plants measuring their potential to cause allergic reactions in humans, it has a rating of 10 out of 10. And as the olive tree is wind-pollinated the pollen if inhaled, can cause headache, blocked sinuses, breathing difficulties and serious asthma attacks.

Orange jasmineMurraya paniculata. Family Rutaceae. A tropical evergreen tree or shrub from Asia is a common specimen for bonsai. It has glossy leaves and white scented fragrant flowers that can remain throughout the growing season and fruit ranging from orange to red, resembling the kumquat. The orange jasmine has no known toxins harmful to humans, but the flowers are highly allergenic and can cause headache, blocked sinuses and breathing difficulties and in some instances severe asthma.

PlumPrunus Spp. Family Rosaceae. Is a diverse group having many species between 19 and 40 according to taxonomists. Arguably the most common plum trees used in bonsai are the European plum Prunus domestica and the Japanese plum Prunus salicina. The flowers are fragrant and vary from white to cream, to various shades of pink. The fruits are usually globose to oval between 2cm to 6cm in size with firm flesh surrounding a hard seed pod. Plum seeds contain the toxin cyanogenic glycosides including amygdalin that decompose into a sugar molecule resulting in the production of Hydrogen cyanide gas, which is extremely poisonous and flammable.

PodocarpusPodocarpus neriifolius. Family Podocarpaceae. There are approximately 97 to 107 species in the genus that are related to conifers and can be found in bonsai collections. Podocarpus are evergreen with cones forming a brightly coloured fleshy, berry-like receptacles inviting birds to feed and in so doing the seeds are dispersed through their digestive tracts. Podocarpus are also related to yews, thus their leaves, stems, bark and pollen are cytoxic. In spring and early summer, the male Podocarpus blooms and releases the cytotoxic pollen and exposure to this can create an effect mimicking the cytotoxic side effects of chemotherapy, where blood cells or bone marrow are most at risk of developing serious infections.

Privet­ – Ligustrum vulgare. Family Oleaceae. A species native to Europe, Australia, Africa and Asia is commonly used in bonsai. Species include the Japanese privet Ligustrum japonicum, Chinese privet Ligustrum quihoui, which are mainly used for ornamental plants and Ligustrum ovalfolium for hedging purposes. The latter if managed regularly is quite decorative, but if left to its own devices will become unruly. Privet leaves and bark have bitter properties, which in China are used for making herbal teas. However, privet species that yield fruit should not be ingested as they are toxic; symptoms include nausea, headache, abdominal pains, vomiting, diarrhoea, low blood pressure and weakness.

QuinceCydonia oblonga Family Rosaceae. Include such species as Chaenomeles japonica and Pseudocydonia sinensis that are small deciduous fruit and flowering trees. The flowers borne in clusters vary according to the species from pale pink to red and both species bear fruit in the form of a pome, which is bright golden-yellow at maturity. Although the fruit is edible, it is astringent and can cause a shrinking or constriction of the body tissues for example, a dry puckering of the mouth due to the tannins present. The quince has been used for both culinary and medicinal purposes but it is poisonous, as the seeds contain nitriles that if ingested will be hydrolysed by the stomach acid producing hydrogen cyanide.

RhododendronSpp. 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 rhododenron 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 PeaAbrus 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. Abrin 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.

RowanSorbus 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, and orange to red berries. And 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.

SnowberrySymphoricarpos 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 and are 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 treeEuonymus 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. But the fruits are poisonous containing 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.

SpurgesEuphorbia Spp. Family Euphorbiaceae. This genus has 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.

TamaracLarix laricina. Family Pinaceae. Known as the black, eastern, red and American larch, is native to north America and Canada and is 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.

TitokiAlectryon 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 its fruit are a pinky-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, because it contains tannins and cyanide-producing poisons in its bark, leaves and fruit that if ingested can cause; vomiting, gastroenteritis, diarrhoea, delirium, kidney failure and at worse fatality.

Tea tree (Chinese)Camellia sinensis. Family Theaceae. Camellia sinensis 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 can cause; dizziness, headaches, palpitations, indigestion, constipation and insomnia. Moreover, excessive intake or over indulgence can be harmful to pregnant women.

In toxic bonsai part IV we will conclude the alphabet on toxic bonsai, until then BW, N.