Ricinus communis is fast growing, tall and dramatic with huge leaves and interesting flower spikes that add drama to borders and beds. Also known as the Caster Oil plant, the plants can grow so fast that they can be used as a very large and dramatic annual in the garden.
Ricinus communis var. gibsonii is a compact variety with gorgeous dark red, metallic foliage. It grows to a reasonable garden height of around 150cm (5ft) The palmate leaves have deeply incised lobes and grow 30 to 75cm (12 to 30in) across. The plants have red stems and in late summer clusters of creamy yellow blooms are followed by stunning scarlet seeds pods.
The plants are remarkably architectural and can be used very effectively in the centre of island beds or at the back of the border. In frost free areas they are grown in large borders or allowed to naturalise in the back of the landscape. In frosty climates, the Castor Oil plant is one of the best ways to quickly create a tropical effect in the garden.
Sowing: Sow indoors in April or outside from late May
Caster bean plants are tender plants which grow quickly. They should not be sown too early otherwise you have 3ft plants by end May. Seeds can also be sown directly where they are to grow, but do need quite high temperatures to germinate, so indoor sowing often gives better results. Remember that the seeds of Ricinus are poisonous and wash your hands when you have finished sowing.
Sow the seeds 2 to 3cm (1 to 1½in) deep in individual pots containing compost. Make sure the compost is moist. Place the pots on your sunniest windowsill. For best results keep the seeds at a temperature of 24°C (75°F). Germination usually takes 14 to 21 days. Soaking the seeds overnight can speed up germination, however it is not necessary.
Grow on at 14°C (58°F). When the seedlings are well rooted in the small pots, they can be transplanted to 15cm (6in) pots to grow on. Planting into larger pots before they become root-bound prevents premature flower production.
Place them in a cold frame to harden them off and transplant the plants outdoors into their final position once all frosts are over usually around mid to late May, when the plants are around 20 to 30cm (8 to 12in) tall. Space at least 12in (30cm) between plants. They prefer a sunny position and rich soil.
This fast growing plant tends to grow straight up at first, developing branches later in the season to form a well-proportioned shrub with sturdy stems and a dense canopy. Plants can be pruned to limit the size, or may need staking if top heavy; otherwise this plant needs very little maintenance.
It is common for very large varieties to bend at the base under their own weight. They then appear to shift along the border and encroach on other plants. This can be prevented by tying the plant to a broad stake.
High fertilisation levels are required. Fertilise the plants weekly using a complete balanced fertiliser.
Immature leaves are green with copper and red shades developing as the plant matures and grows over 24in (60cm). Leaf shades often very throughout the plant. The deepest red shades develop strongest when positioned in full sun.
Temperatures below 10°C (50°F) are tolerated for a short time, but growth is inhibited. The plant is killed when the temperature drops below 0°C (32°F).
The seeds, or "beans" (they are not true beans), are only produced where the growing season is long enough (140 to 180 days). The shiny, intricately mottled seeds are quite attractive, each with their own unique design in colours of black, gray, brown, yellow-brown, maroon and white. The intricately mottled seeds have a spongy caruncle at one end which helps absorb water for germination when planted. Seeds remain viable for 2 to 3 years.
Beds and borders, Exotic or Sub-Tropical. Container planting.
Ricinus is planted as a hedge plant in India, as a shade plant in Costa Rica and for sand dune stabilisation in Libya. When grown outdoors it is said to rid the garden of moles and nibbling insects.
About half the weight of the seed is a thick, yellowish or almost colourless oil that has been used for centuries in many applications. The oil was used in ancient times as fuel for lamps, today in rural areas it is used on its own or mixed with kerosene, it imparts a cooler, brighter light, burns more steadily and generates little soot.
Castor oil is primarily used as a high quality lubricant and a versatile raw material in the chemical industry besides being widely used in Medicine. Its high lubricity, high viscosity over a wide range of temperatures coupled with its insolubility in petrochemical fuels and solvents, makes it suitable for use in equipment operating under extreme conditions such as in arctic zones and in aviation.
The oil is used in paints and varnishes, for water-resistant coatings, in high-performance motor oils, soap, inks, and plastics. Other derivatives are used in polishes, as solid lubricants, in synthetic perfumes and other products.
Plants are grown commercially for oil production primarily in India and Brazil, but also in some parts of the U.S. and other countries.
Castor Oil Pomace, the residue after crushing, is used as a high-nitrogen fertiliser. A fibre for making ropes is obtained from the stems and cellulose from the stems is made into paper and cardboard. The attractive castor seeds are used in jewelry making, mainly for necklaces and bracelets.
Ricinus communis is indigenous to the south-eastern Mediterranean Basin, Eastern Africa, and India, but is widespread throughout tropical regions and widely grown elsewhere as an ornamental plant.
It has escaped cultivation and become naturalised almost everywhere in the world that has a tropical or subtropical climate. Castor Bean grows wild on rocky hillsides, and in waste places, fallow fields, along road shoulders and at the edges of cultivated lands.
It is a species of flowering plant in the spurge family, Euphorbiaceae. Unlike many members of the euphorbia family, this plant does not have milky latex sap, but has a watery sap
The genus name Ricinus has a circular definition, it is usually given as having the meaning of a ‘tick’ because the skin of the castor beans looks like a tick - but there is a tick called iloxedes ricinus named because its skin looks like a castor bean.
The name is possibly taken from the Latin ri meaning ‘thing’ and cinus meaning ‘destruction’, ‘the dead’ or ‘ruin’, thus has the meaning of ‘the thing which brings death’.
The species name communis simply means common.
The common name of the Castor Oil plant probably comes from its use as a replacement for castoreum, a perfume base made from the dried perineal glands of the beaver (castor in Latin). Another common name, Palm of Christ, or Palma Christi, that derives from castor oil's reputed ability to heal wounds and cure ailments.
Although the seed is called the castor bean, despite its name, is not a true bean. An unrelated plant species, Fatsia japonica, is similar in appearance and known as the false castor oil plant.
The toxicity of raw castor beans due to the presence of ricin is well-known. The seeds are poisonous to people, animals and insects. The toxin provides the castor oil plant with some degree of natural protection from insect pests such as aphids. In fact, ricin has been investigated for its potential use as an insecticide. The castor oil plant is also the source for undecylenic acid, a natural fungicide.
Commercially available cold-pressed castor oil is not toxic to humans in normal doses, either internal or externally.
One of the main toxic proteins is ricin. If the seed is swallowed without chewing, and there is no damage to the seed coat, it will most likely pass harmlessly through the digestive tract. However, if it is chewed or broken and then swallowed, the ricin toxin will be absorbed by the intestines. Although the lethal dose in adults is considered to be four to eight seeds, reports of actual poisoning are relatively rare.
It is recommended that this plant is grown out of reach of children, or simply remove the seed heads to prevent the formation of seeds. If you are a nervous parent then perhaps this plant should be avoided altogether.
However ....The seeds are generally held quite high on the plant, certainly out of reach of any very small children. The plants are also strong and unlikely to fall over in windy conditions where the seeds could be presented. Actually removing the seeds from their pods is also quite difficult.
Once they are ripe the seeds pods explode sending the seeds every where. Again we have a 'however': the seeds do not reach this stage during the summer growing season. When stored in the greenhouse to over winter, the seed pods of the castor oil plant begin to explode early in the new year.
At first you may be under the impression that those pesky boys from next door are throwing gravel over the garden wall, trying to annoy you. Then you remember there are no charming pranksters next door as a Ricinus communis seed lands squarely between the eyes. It is at this stage, when the greenhouse floor is awash with seeds, that they are there most dangerous to foraging children. Again if you have children that naturally put anything they come across into their mouths, you probably should avoid this plant.
There are many plants in our gardens that are poisonous, teach your children about this and other plants.
Education is always more powerful than ignorance.
- Additional Information
Packet Size 20 Seeds Seed Form Natural Seeds per gram 2 seeds per gram Family Euphorbiaceae Genus Ricinus Species communis Cultivar var. gibsonii Common Name Castor Oil Plant Other Common Names Castor Bean Plant Hardiness Tender Perennial often used as an Annual Flowers Creamy white flowers with scarlet seed pods Natural Flower Time Late Summer Foliage Dark red, metallic palmate leaves Height 150cm (5ft) Spread 90 to 120cm (3 to 4ft) Aspect Full sun. Soil Moist, fertile soil Germination 14 to 21 days at 24°C (75°F). Notes Seeds are poisonous