Carissa Macrocarpa Boxwood Beauty
Growing Carissa Shrubs: How To Grow A Carissa Natal Plum
Natal Plums are known as the most beautiful plants in nature. They have been used for centuries in many cultures around the world. These trees are native to tropical regions of Africa, Asia, Australia and New Zealand. In fact they were originally brought from South America by Spanish explorers. The name “carissa” comes from the Latin word carbus which means chestnut tree.
The carissa is one of the most popular ornamental trees in gardens because it’s easy to grow and produces large, showy fruit. It grows up to 30 feet tall and 10 feet wide. Its bark is dark brown with light streaks. Its leaves are greenish white and grow 2 inches long at the tips and 6 inches across their whole length.
Plants produce flowers in spring and summer. There are two kinds of carissa varieties, orchids and pines. The carissa is native to the tropical forests of Central and South America, but it has spread throughout much of the world due to human activity. Some species have become invasive in other parts of the world where they compete with indigenous species for space, water, sunlight and food sources. They are considered an invasive pest in many parts of the world and in some cases have become a threat to the natural environment.
Natal plums are grown as ornamental trees or hedgerow plants. These plants produce small, yellow flowers that give way to small, yellow or orangey fruits. The flesh is soft and the taste is slightly sour and astringent. The fruit can be used to make preserves, marmalade, jelly or wine.
The plant prefers subtropical or tropical climate and moist soil. It does not tolerate frost or dryness. The plant is frost sensitive so it’s best to plant it in warm regions where it can grow for many years.
The plant has been declared a noxious weed in some Australian states and is banned from sale, distribution and propagation. There have been efforts to remove it from areas near populated areas. It can take over natural ecosystems and exclude native species from growing in that area. It also out-competes other species for food.
The carissa is a shrub or small tree that reaches a height of 2-5 meters. The leaves are evergreen, alternate, simple, entire, oblong to lanceolate, 7-15cm long and 1.5-3cm wide. The flowers are small, white, borne in short cymes and followed by globular reddish-black fruits.
Carissa macrocarpa is the most common species of carissa in South Africa. Unlike most other members of the genus, C. macrocarpa is autogamous. It also produces much larger fruits and is less thorny.
Carissa is a genus of about 20 species of flowering plants in the family Apocynaceae, originally from Africa, but now spread into the warmer parts of Asia and the Pacific region.
These evergreen shrubs vary in size from medium to large and grow either as single stems or more usually with several stems out of the ground. The branches are slender and sharp angled.
The leaves are opposite, simple broad lanceolate and glossy. They are 3-12cm long and 1-5cm wide. The leaf margins are entire (smooth) and they have a very distinct pale green to yellowish color fading towards the center of the leaf.
These plants usually have several small flowers growing in clusters at the tips of the branches. There are many small flowers in a cluster and these are followed by oval fruits. The fruits have a distinct ribbed casing and are yellowish to dark purple when ripe.
These shrubs are native to the Far East but have been spread by man to many other countries around the world.
The shrubs prefer moist soil, full sun and well-drained soil.
The shrubs are known to be invasive in new regions due to their extensive root systems. They spread rapidly and could damage ecosystems. Creeping into forest areas, they can dry out the soil and deprive other plants of water.
The stems and leaves are armed with curved, hooked prickles which easily catch in the coats and trousers of passers-by and readily spread the plant to new locations.
The fruit is an oval capsule which contains several large seeds.
The shrub is sometimes grown as an ornamental, particularly in subtropical and tropical areas for its showy white flowers.
The plant is also grown for its edible fruit, which are either yellow or orange.
The fruits are edible when ripe but the plant is considered a weed in many areas because the prickles on the branches can easily catch on clothes and bags etc. and the stems break off easily so it spreads into other areas. The fruits are an important food source in some parts of Asia where they are eaten both raw and cooked.
The fruit is also said to be an effective treatment for kidney disfunction.
Carissa fruit contains polyphenolic compounds, carotenoids and alkaloids.
The main polyphenolic compound is called carisin. It is a non-protein amino acid which can lead to cell mutation and cancer.
It is also used to treat malaria.
The fruits are eaten by a number of animals including primates and birds.
Pigs don’t eat the fruits due to the toxic compounds.
Carissa fruit contains at least 15 different alkaloids including carissiamine, carissidine and carisoprodol.
The leaves can be used as a fish poison.
The leaves contain the same toxic alkaloids as the fruit. They can be used to make fish unconscious so that they can be easily caught with your bare hands.
It is used in some parts of Africa to catch small fish for food. The juice squeezed from the leaves is used as a poison and the remaining parts of the plants are discarded after use.
The shrub is sometimes grown as an ornamental.
The beautiful flowers are white and have a very sweet smell.
It is sometimes used in herbal medicines. Various parts of the plant can be used to make preparations for the treatment of various medical conditions.
It is sometimes used to make dyes for fabrics.
The shrub can be invasive in some areas and can damage nearby plants by out-competing them for water and nutrients.
It is now considered a weed in many parts of the world. It can survive in many types of soil and grows in a wide variety of climates.
The plant can be controlled to some extent by cutting off the flower heads before they have a chance to spread their seeds.
It has become a major weed in parts of Australia and Florida and is considered highly invasive.
The species is native to the Old World tropics including Africa, southern Asia and islands of the western Indian Ocean but is now present on all continents in varying degrees of abundance. It is found naturally in bushland, woodland, grasslands, open areas, river banks and even deserts. It grows easily in dry conditions and can survive long periods without water. It favours acidic soils.
The plant can grow to a height of about 3 meters and can live for more than 10 years. The branches are woody and the shrub has green leaves that have a silver-white underside.
Is a close relative of the common petunia. It has large clusters of fragrant flowers that are white or purple in colour.
The shrub grows rapidly and can produce many branches. It can be propagated easily from cuttings. The shrub grows well in poor soils and doesn’t need much water.
The seeds can be collected by clearing the dead flowers off the plant and laying a cloth on the ground underneath. The seeds will collect on the cloth as they fall.
The plant can spread rapidly both by root suckers and seed, particularly in areas where there is little competition from other plants. It can grow from seeds that are dispersed by water.
It can grow in very arid conditions and can survive long periods without water.
It can grow from cuttings or even from root fragments, so it can easily spread into new areas. The cuttings can be carried by animals or water into new habitats.
It is sometimes used in bioremediation of soil contaminated with metals such as lead and uranium. This may increase the concentration of toxic elements in its tissues.
The wood from the shrub is sometimes used as a source of fuel.
Domesticated animals can be poisoned by eating the fruit.
It is a host plant for the purple honeyeater and musk butterfly.
The leaves contain N-methylconiine, an alkaloid that can be poisonous to livestock, particularly sheep. In some parts of Africa, the leaves are eaten by goats.
The leaves contain the toxic alkaloid cytisine. This is a partial opioid agonist and is used in some tobacco substitutes.
The flowers are fragrant and have been used in various perfumes.
It has been cultivated as an ornamental garden plant.
In the past it was sometimes grown as a medicinal herb, particularly in India.
It contains triterpenes, saponins, sterols and flavonoids.
Some varieties produce brightly coloured flowers. The flowers can also be made into jams, preserves and syrup.
It contains a good amount of vitamin C.
Seed – sow March to June in situ. Germination usually occurs within 1 – 6 weeks.
Seed can also be sown in autumn but the seed will not germinate until the following spring. If sowing in autumn soak the seed in water for 24 hours before sowing. The seed can be sown either in situ or in containers. A light covering of moss or sand/loam mixed with manure is recommended to provide the seed with the best conditions for germination.
Cuttings – take cuttings from growing plants in late spring to early summer. Leave the cutting in a shady place for a few days so that a small amount of callus forms on the cut end. Cuttings from actively growing tips fertilized with plenty of nitrogen do well.
Pour boiling water over the cuttings and allow them to cool for 20 minutes.
Make a slight diagonal cut just below a node and at the base of the cutting.
Place the cuttings in a partly shaded position (if outside) or in the shade of a tree or temporary shed (if inside).
Mist the cuttings several times a day. After a few weeks, when there is adequate root development, transplant the cuttings to pots filled with a mixture of 3 parts soil to 1 part compost and keep in a lightly shaded position.
When plants are growing well, transplant into their permanent positions.
Indigenous to tropical Asia, particularly the Indian subcontinent. It is found throughout most of India and Sri Lanka and also in parts of Southern China, Southeast Asia and Australia.
It grows in thickets, waste places, forest margins, on marshy ground, along river banks, etc. A common weed in many parts of India.
It has been introduced into many parts of Africa and has become a noxious weed in some countries there.
The yellow-flowered form has been introduced into horticulture and there are numerous named varieties available.
It is a half-hardy, medium-sized shrub, usually growing to 2 – 3 metres but can reach 4 or even 5 metres in good conditions.
In frost free areas, it can be grown as a large shrub or even as a small tree.
The flowers range in colour from bright yellow through orange and red to almost purple.
The leaves are shiny green and resemble nettle leaves.
It tolerates most soil types but prefers a moist free-draining soil.
It will grow in sun or part shade but the flowers are smaller and less abundant in shade.
It is a tough plant and tolerant of dry conditions but grows bigger and flowers better with adequate water.
It does have a few pests and diseases that can affect it, though these are not too severe. Scale insects are a common problem and can be treated with nicotine sulphate. Mealy bugs also sometimes occur.
Glossy leaves can indicate an iron deficiency, for which an application of iron sulphate will suffice as a treatment.
There are numerous species and hybrids of “Bougainvillea”, many of which have different cultural requirements. They can be separated into two groups – the South American Bougainvilleas and the Australian/Asian Bougainvilleas.
The South American varieties (including B. truncata) are hardy and free-flowering and can be grown outdoors in frost free areas such as the coast or the far south of New South Wales. They have large flowers in shades of white or pink.
The Australian/Asian varieties are less hardy and need to be grown under glass with protection or outside in a frost free area. These include all the colours other than white, together with the distinctive bracts (modified leaves) which give the group its name.
It is important not to intermix the two groups when growing them as some of the South American varieties can be highly invasive.
All parts of the plant are poisonous and contains a toxic alkaloid similar to nicotine.
All parts of the plant, including the fruit, are highly poisonous and can cause death.
It is said that cattle that graze on it after drying will die.
Sources & references used in this article:
An integrated approach for harvesting Natal plum (Carissa macrocarpa) for quality and functional compounds related to maturity stages by A Ndou, PP Tinyani, RM Slabbert, Y Sultanbawa… – Food chemistry, 2019 – Elsevier
Carissa macrocarpa (Apocynaceae): New to the Texas flora by JR SINGHURST, WC HOLMES – … 2010-19: 1-3 …, 2010 – doc-developpement-durable.org
RHIZOCTONIA SOLANI, THE CAUSE OF AERIAL BLIGHT OF NATAL-PLUM CARISSA GRANDIFLORA, IN FLORIDA by SA Alfieri Jr, CP Seymour, JC Denmark – fdacs.gov
Food, pharmaceutical and industrial potential of Carissa genus: an overview by S Patel – Reviews in Environmental Science and Bio …, 2013 – Springer