Toxic Bonsai Part II
Ginkgo biloba – Family Ginkgoaceae. Also known as the maidenhair tree native to China is the only living species in the division Ginkgophyta, as all others are now extinct. Its fruit is used for culinary purposes and in traditional Chinese medicine and is considered by some to contain aphrodisiac properties. However, the seed pulp has toxins that are not destroyed when cooked and if eaten in large amounts poisoning by methyl pyridoxine, (neurotoxin) can cause epileptic seizures. In addition, the sarcotesta or fleshy seed coat is poisonous and disposable gloves are required as they are able to cause dermatitis and or blisters. Other side effects include; nausea, vomiting and diarrhoea.
Guelder rose – Viburnum opulus. A deciduous shrub can be found in woods, hedges and in areas containing a lime-rich soil compound. The tree has large white flowers with smaller yellow ones on the inner part of the cluster, the white flowers are infertile whilst the yellow ones are fertile. In autumn the flowers produces red berries with a single seed in each. All parts of the tree are poisonous to humans as they carry toxins such as iridoid glycoside, isobutyric Acid, coumarins, tannins and saponins. These can cause severe nausea, vomiting, diarrhoea, swelling and over heating.
Grevillea robusta – Family Proteaceae. Commonly known as the Australian silver oak although uncommon can be found in European bonsai collections. This evergreen tree with its feather like leaves similar to a fern frond is known for its prolific growth and produces golden orange blooms. The flowers and fruit of G. robusta are poisonous, they contain hydrogen cyanide sometimes referred to as Prussic acid and tridecylresorcinol responsible for severe contact dermatitis.
Honey Locust – Gleditsia triacanthos. Is not a toxic tree unlike its ‘look-alike’ counterpart the black locust, Robina pseudo which is extremely poisonous. The two species can be identified as follows: the black locust has wisteria like flowers and small black seed pods, whilst the honey locust has small clusters of flowers and long seed pods 15–20 cm. Honey locust trees have extremely sharp thorns 3 cm to over 20 cm protruding from the branches, that harden and turn red as they age, then fade to grey becoming brittle as they mature. As a result the honey locust is considered difficult to wire and shape although thorn less varieties (Gleditsia triacanthos var. inermis) are occasionally found growing wild and are available as nursery plants. But there is no guarantee they are free from toxins.
Holly – Ilex. Family Aquifoliaceae. There are 400 to 600 species ranging from evergreen to deciduous trees and shrubs, found in temperate to tropical climates around the world with many shaped into bonsai. The bark is relatively smooth with small nodules known as ‘warts’, the glossy oval leaves are dark green in colour. Holly is dioecious meaning that the flowers of male and female are peculiar to their own sex and tree. These flowers 4 white petals when mature become scarlet berries and are attractive to birds, whom ingest them, but pass the seed through their digestive system intact. However, for humans they are predominantly poisonous as is the rest of the tree. Holly contains such toxins as caffeic, feruloylquinic, chlorogenic and quinic acids, kaempferol, tannins, rutin and theobromine compounds found in all parts of the plant. Holly berries can cause severe vomiting, diarrhoea and nausea that can be fatal for young children if consumed.
Hawthorn – Crataegus. Family Rosaceae. Is a species quite common in bonsai grown for its floral display. The flowers are hermaphrodite, meaning both male and female reproductive parts are contained within each flower. Flowers are highly scented, white or occasionally pink with five petals, and grow in flat-topped clusters, with small pome fruits and thorny branches. Although hawthorn fruit is not toxic if used in herbal remedies and culinary purposes it must be prepared properly. Failure to do so can cause nausea and sedation, cardiac arrhythmia and dangerously low blood pressure if taken in large quantities. Those taking digoxin a medication used to treat various heart problems should avoid hawthorn completely.
Indian Pea – Lathyrus sativus. Family Fabaceae. Although not really considered as bonsai material, is often cultivated for its striking blue flowers, but more importantly as an insurance against famine in third world countries where drought is a major problem. The crop is harmless to humans if ingested in small quantities occasionally, but continuous intake over a prolonged period (3 months) can have serious side effects. The plant produces seeds containing diaminopropionic and neurotixic amino acids and can cause a disorder known as lathyrism. A neurodegenerative disorder causing paralysis of the lower body, emaciation of gluteal muscle and brain damage in children.
Idesia – Family Salicaceae. A tree not normally found in western bonsai collections is common in its native regions of China, Japan, Korea and Taiwan. It is a deciduous tree with greyish-green bark and heart shaped dark green leaves 8 to 20cm in length protruding from a red petiole. Flowers are small, fragrant and yellowish green in colour. The fruit of the Idesia is a small orange berry, which ripens to dark red almost purple in colour, that can be consumed, but as with all wild fruit care should taken in its preparation prior to ingestion. Idesia has no known toxins that are harmful to humans.
Incensed Cedar – Libocedrus decurrens. Family Cupressaceae. Is a popular species for bonsai as formal, informal and literati styles. It contains strong volatile oils including thujone, a ketone that is known to be toxic in large quantities and it is best known as a chemical compound in the spirit absinthe. Thujone has a menthol odour and is considered toxic to the brain, kidney, and liver cells and could cause convulsions if used in too high a dose. It should not be used during pregnancy, breastfeeding or those with kidney weakness.
Jacaranda – Jacaranda mimosifolia, Family Bignoniaceae. Has been cultivated in many temperate parts of the world and also in bonsai thriving in sandy soils with full sunlight. Young trees are unable to withstand cold conditions, but mature specimens are able to tolerate temperatures down to -7°C (19°F) for brief spells. The jacaranda is known for its stunning display of flowers produced in large panicles, with colours ranging from blue to purple and fruit in a flattened oblong pod containing the seeds. Nonetheless, the Jacaranda is said to be toxic, exposure to the pollen can cause skin irritation and rash. Ingesting either and or flowers and seeds can result in, vomiting, nausea and abdominal pain.
Jade tree – Crassula ovata. Family Crassulaceae. Has other common names including, ‘Friendship tree’, ‘Money tree’ and ‘Lucky plant’ and is native to south Africa and Mozambique and is found throughout the world as a common house plant. Arguably, C. ovata is not a true tree in the sense of the word, meaning it does not shed its leaves or needles on an annual basis as deciduous and conifers do. It is a succulent, a water retaining plant that has the ability to thrive on limited water sources. Whereas most conifers and deciduous trees require a constant supply of water that is continuously pumped through its system. In addition, its trunk and branches never become true lignified tissue, they remain soft and fleshy during the plants life. Nonetheless, it is found in many bonsai collections with some attractive results. C. Ovata has rich jade green thick, shiny, smooth, leaves growing in opposite pairs along the branches. Some varieties may have a yellowish-green appearance, whilst others have a red tinge on the edges. The flowers of C. Ovata under the right conditions are small star-like white or pink flowers arriving in early spring. The jade plant is poisonous to domestic pets (dogs and cats) and marginally toxic to humans and if ingested may cause vomiting, diarrhoea, abdominal discomfort, loss of appetite and lethargy.
Jasmine – Gelsemium sempervirens. Family Gelsemiaceae. A relatively common species found in bonsai collections for its individual trumpet shaped yellow flowers, that are strongly scented and appear on the tree prior to the production of new growth. However, all parts of this species are poisonous containing toxins such as strychnine related alkaloids and gelsemine a highly toxic compound that acts as a paralytic and often results in death. In addition, the sap from this plant can cause severe problems if in contact with those having sensitive skin causing rash and swelling.
Juniper – Spp. Family Cupressaceae. This order has many species widely used in bonsai horticulture and it is argued that they are all toxic due to the volatile oils found within the plant. Alpha-pinene, myrcene and sabinene, which if ingested can cause diarrhoea, nausea and hypertension. Although considered by many to be safe for culinary uses, juniper berries if consumed on a regular basis can cause cause serious kidney damage. Pregnant or breastfeeding women are advised to refrain from usage due to the risk of miscarriage. Those taking Telmisartan a prescribe drug, which is used to treat high blood pressure (hypertension) should refrain from ingesting any part of this plant.
Kentucky coffee – Gymnocladus dioicus. Family Fabaceae. A species native to north America is also used in bonsai. Its rough ash-grey bark similar to that of oak can fall or peel away from its surface leaving scarring and indentations, which adds character to the tree. Its flowers are dioecious and has fruit in the form of a hard-shelled bean in pods from 13cm to 25cm. (5 to 10 inches) The seeds are considered poisonous as they contain the toxic alkaloid cytosine, that if consumed can cause respiratory difficulties, which can have fatal results. However, it is argued that if the seeds are roasted, the cytosine is neutralized, but for those with respiration problems it is not a risk worth taking.
Kumquat – Fortunella japonica. Family Rutaceae. The species has no known toxins harmful to humans and is usually grown as an ornamental plant, but is found in bonsai collections. The fruit resembles a small orange a little larger than a grape, its peel has a sweet flavour whilst the inner pulp is sour but is edible when cooked. It is also ingested in its raw state, but those with a sensitive digestion system should refrain from doing so due to the concentration of oils (Limonene) and acids within the fruit. Which can cause diarrhoea, nausea and other abdominal complaints.
Kurrajong – Brachychiton populneus. Family Malvaceae. Is native to Australia and found in various habitats from wet coastal districts to semi-arid regions. The bell-shaped flowers range in colour from pale cream to pink with simple pointed shaped leaves. The seeds are covered in small stiff irritating hairs, which have to be removed prior to roasting and ingesting as they contain toxins. Although these are not considered dangerous to humans they can be to domestic pets, sheep and cattle causing lameness, tremors, collapse and in some cases fatality depending on the victims disposition.
Laburnum – Family Fabaceae. Is a genus of two species of trees that are Laburnum anagyroides known as the common laburnum and Laburnum alpinum the alpine laburnum. They are often found in bonsai collections due to their colourful yellow pea-like flowers. That are in pendulous leafless racemes 10–40 cm (4–15.5 in) similar to the wisteria, making them very popular trees. However, all parts of the tree are poisonous; roots, bark, wood, leaves, flower-buds, petals and seeds as they contain the toxin cytosine a nicotinic receptor agonist that produces a biological response. Symptoms may include intense lethargy, vomiting, convulsion, coma and severe diarrhoea.
Laurel (Cherry) Prunus laurocerasus. Family Rosaceae. Is a shrub often used for topiary in hedging and also in bonsai as it is easily shaped. The leaves are a shiny dark green with creamy white flowers and fruit that turn black when ripe. The whole plant is poisonous containing the toxin hydrogen cyanide, also known as prussic acid and identifiable by its strong almond-like smell and bitter taste. Symptoms can include breathlessness, weakness, spasms, convulsions, coma and respiratory failure.
Manchineel – Hippomane mancinella. Family Euphorbiaceae. Classed as an endangered species is a flowering and fruiting tree native to Florida, Mexico and the Bahamas growing among mangroves and in coastal waters. Its fruits are green and round resembling a small apple, hence its common name the ‘Beach apple’. H. mancinella is an evergreen tree with reddish-grey bark, glossy oval green leaves, greenish-yellow flowers and grows to a height of approximately 15m. (49ft) It is also known in Spanish as ‘Manzanilla de la muerte‘, the ‘Apple of death’ and is considered one of the most dangerous trees in the world. All parts of the tree are extremely poisonous with arguably the sap being the most toxic as it contains phorbol a member of the tiglian family of diterpenes. Even the smallest amount diluted in water can cause severe blistering of the skin and ingesting the fruit can cause intense gastrointestinal problems that can have fatal results. Manchineel is cultivated for its timber source, but little is known of its use in bonsai.
Mistletoe – Viscum album. A hemiparasitic plant in the order Santalales. A mistletoe seed attaches itself to a tree by a structure called the haustorium and is able to germinate independently, but as it develops it penetrates the branch of its host absorbing nutrients and water. The European mistletoe has evergreen leaves in pairs with waxy white berries in clusters of two to six, that contain the toxins polysaccharides, alkaloids, and lectins. Which can cause blurred vision, nausea, abdominal pain, diarrhoea, blood pressure changes that can be fatal. Those taking Telmisartan a prescribe drug, which is used to treat high blood pressure (hypertension) should be aware of potential problems. Mistletoe is found in bonsai, but is uncommon as it can affect other species within a collection.
Mock orange – Philadelphus coronarius. Family Hydrangaceae. A species of flowering plant native to Southern Europe is a deciduous shrub growing to approximately 3 m tall by 2.5 m wide and often found in bonsai collections. What makes this a popular collectable species is because of its bowl-shaped double white flowers on prominent stamens, that are highly fragrant. The ‘toothed’ dark green leaves turn to yellow in autumn adding more colour to the plant. Yet the seeds and flowers carry toxins that although considered mild and not life threatening, can cause nausea, vomiting, diarrhoea and skin rash if consumed. But much will depend on an individual’s digestive system.
Myrtle – Myrtus communis. Family Rosopsida. A common species found in bonsai has reddish brown bark that is apt to peel off in mature plants. The flowers usually white in colour have five petals and numerous long stamina and can be heavily scented. The leaves are small, narrow and dark-green and filled with oil, which is visible as small dots when held against a light. This oil is slightly toxic and may cause headaches, nausea, indigestion, and may colour urine purple if consumed in large quantities.
In toxic bonsai part III we continue the discussion on species ‘N’ to ‘T’ until then BW, N.