Persea americana

Fast-growing evergreen tree reaching 15m tall and 25m wide. Produces small flowers pollinated by bees and insects; not self-fertile. Requires full sun and well-drained soil, tolerating mildly acid to very alkaline conditions. Prefers moist soil but handles drought once established. Tolerates strong winds but not coastal salt spray. Hardy to UK zone 10.

Description

A small to medium sized tree. It grows 8-10 m high. Trees can grow to 25 m high. The leaf stalk is 1.5-5 cm long. Leaves are entire, oval and 5-40 cm long. Flowers are greenish, small and on the ends of branches. Clusters of flowers may contain 200-300 flowers. Normally only 1-3 fruit develop from each cluster. The fruit is pear shaped or round. It can be 7-20 cm long. The fruit are greenish-yellow with some red coloration. The fruit has greenish yellow flesh and a large round seed. There are 3 named races - West Indian, Guatemalan and Mexican.

Edible Uses

The fruit is typically eaten raw. The flesh has a buttery texture and a mild, oily flavour and can also be used as a sandwich spread or in ice creams. The pear-shaped fruit grows up to 12cm long. A non-drying oil from the fruit has a mild, pleasant taste and is used as a salad dressing, particularly with strong-flavoured leaves such as chicory, rocket, and watercress. A tea can be made from the leaves, and toasted leaves are used as a flavouring in stews and bean dishes.

Traditional Uses

The pulp of the fruit is eaten raw or cooked. It is eaten in salads, soups, sandwiches, spreads, ice cream, and also in tortillas and in wine. The fruit are mixed with sugar and water to make a drink. Oil is extracted from the flesh. It is used in salad dressing. The leaves can be used for tea sweetened with sugarcane juice. Toasted leaves are used to season stews and bean dishes. Caution: Some people are allergic.

Medicinal Uses

The avocado has a long history of medicinal use, with most parts of the plant employed in traditional remedies. Research has demonstrated anti-cancerous activity in extracts of the leaves and fresh shoots, as well as antihypertensive activity in leaf extracts. The leaf and seed contain cyanide. Oil from the seeds contains steroids used in pharmaceuticals, and seed extract has an erythroagglutinating property. The fruit contains reductase and transferase enzymes. The leaves are astringent, carminative, antitussive, emmenagogue, and hypotensive. An oral infusion of the leaves treats dysentery, relieves coughs, lowers blood pressure, treats liver obstructions, promotes menstrual flow, and helps clear high uric acid levels that could lead to gout. Combined with Tripogandra serrulata, the leaves are used as a remedy for biliousness. The bark is astringent, carminative, antitussive, and emmenagogue, and is used to treat diarrhoea. The fruit pulp is emollient, carminative, and helps lower blood cholesterol levels. Mashed fruit pulp is considered a nourishing food with aphrodisiac properties. Unripe fruit is used to induce abortion. Applied externally, the pulp is cooling and soothing to the skin, and is applied to suppurating wounds and to the scalp to promote hair growth. The skin of the fruit has anthelmintic properties and is used to expel worms. The ground seed is made into an ointment for treating skin conditions including scabies, purulent wounds, scalp lesions, and dandruff. Oil extracted from the seeds has astringent properties.

Known Hazards

Avocado leaves, bark, skin, or pit are documented to be harmful to animals; cats, dogs, cattle, goats, rabbits, rats, guinea pigs, birds, fish, and horses can be severely harmed or even killed when they consume them. The avocado fruit is poisonous to some birds, and the American Society for the Prevention of Cruelty to Animals (ASPCA) lists it as toxic to horses. Avocado leaves contain a toxic fatty acid derivative, persin, which in sufficient quantity can cause colic in horses and without veterinary treatment, death. The symptoms include gastrointestinal irritation, vomiting, diarrhea, respiratory distress, congestion, fluid accumulation around the tissues of the heart, and even death. Birds also seem to be particularly sensitive to this toxic compound. The leaves of the Guatemalan variety of P. americana are toxic to goats, sheep, and horses.

Distribution

A subtropical plant. Trees grow from sea level up to 2250 m altitude in the tropics. It cannot stand water-logging. Branches are easily damaged by wind. It needs to be in a frost free location or where frosts are rare. West Indian varieties thrive in humid, tropical climates and freeze at or near O°C. Mexican types are native to dry subtropical plateaus and thrive in a Mediterranean climate. They are hardy -4 to -7° C. They are salt sensitive, has the smallest fruits and the thinnest skin. The best daytime temperature is 25-33°C. Guatemalan types are native to cool, high-altitude tropics and are hardy -1° to -3° C. It does best with neutral or slightly acid soil. West Indian avocadoes can stand some salinity. They need a well aerated soil. Growth is disrupted when soil temperatures are below 13°C. It needs high humidity at flowering and fruit set. It can grow in arid places. It grows in Miombo woodland in Africa. In Argentina it grows between 1,500-1,800 m above sea level. It suits hardiness zones 9-11. In Sichuan and Yunnan.

Where It Grows

Africa, Amazon, Angola, Antigua & Barbuda, Argentina, Asia, Australia, Bangladesh, Barbados, Belize, Benin, Bermuda, Bhutan, Bolivia, Botswana, Bougainville, Brazil, British Indian Ocean Terr., BIOT, Burkina Faso, Burundi, Cambodia, Cameroon, Cape Verde, Caribbean, Central Africa, Central African Republic, Central America*, Chad, Chile, China, Colombia, Congo, Congo DR, Cook Islands, Costa Rica, Côte d'Ivoire, Cuba, Djibouti, Dominica, Dominican Republic, East Africa, East Timor, Easter Island, Ecuador, Egypt, Equatorial Guinea, Eswatini, Ethiopia, Europe, Fiji, FSM, France, Gabon, Gambia, Georgia, Ghana, Grenada, Guam, Guatemala, Guiana, Guianas, Guinea, Guinée, Guinea-Bissau, Guyana, Haiti, Hawaii, Himalayas, Hispaniola, Honduras, India, Indochina, Indonesia, Israel, Ivory Coast, Jamaica, Kenya, Laos, Lesotho, Liberia, Madagascar, Malawi, Malaysia, Maldives, Mali, Mariana Islands, Marquesas, Mauritania, Mauritius, Mediterranean, Mexico*, Middle East, Mozambique, Myanmar, Namibia, Nauru, Nepal, New Zealand, Nicaragua, Niger, Nigeria, Niue, North America, Northeastern India, Pacific, Panama, Papua New Guinea, Peru, PNG, Philippines, Pohnpei, Puerto Rico, Rotuma, Rwanda, Sahel, Samoa, Sao Tome and Principe, SE Asia, Seychelles, Sierra Leone, Sikkim, Solomon Islands, Somalia, South Africa, Southern Africa, South America, South Sudan, Spain, Sri Lanka, St Lucia, St. Vincent and Grenadines, Suriname, Swaziland, Tanzania, Tasmania, Thailand, Timor-Leste, Togo, Tonga, Trinidad and Tobago, Turkey, Türkiye, Uganda, USA, Vanuatu, Venezuela, Vietnam, Virgin Islands, West Africa, West Indies, West Papua, West Timor, Zambia, Zimbabwe,

Cultivation

It grows best in areas where annual daytime temperatures are within the range 14 - 40°c, but can tolerate 10 - 45°c. When dormant, the plant can survive temperatures down to about -4°c, but young growth can be severely damaged at -1°c. It prefers a mean annual rainfall in the range 500 - 2,000mm, but tolerates 300 - 2,500mm. Prefers a rich, neutral to alkaline soil and a position in full sun. Succeeds on all kinds of soil. Requires a well-drained soil, the plant is intolerant of water-logging. West Indian rootstocks are fairly tolerant of saline conditions, though other forms are intolerant. Prefers a pH in the range 5 - 5.8, tolerating 4.5 - 7. Requires a position sheltered from strong winds. Seedlings take 6- 8 years to produce fruit, whilst grafts can start fruiting in their second year. Yields of 15 tonnes per hectare have been recorded, but averages are about half that figure. Mature fruit can be left hanging on the tree for weeks without damage. The three main races of Avocado are as follows. There are many named varieties of each race:- Mexican. This is the hardiest form, succeeding in subtropical climates and not well adapted to lowland tropical conditions. It can withstand short periods when temperatures drop as low as -6°c. The optimum temperature for growth is between 14 - 25°c. It has the highest oil content, over 20% and up to 30%. Guatemalan. This form is semitropical. It can withstand short periods when temperatures drop as low as -4?c. The optimum temperature for growth is between 15 - 28°c. It has a medium oil content generally between 10 - 20%. West Indian. This form is wholly tropical and grows well in a lowland tropical climate. It can grow in a temperature range of 12 - 40°c, though the optimum is between 24 - 32?c. It has the lowest oil content, generally below 10%, down to around 3%. Although the flowers are hermaphrodite, the male organ produces pollen when the females are not receptive and so each tree is functionally self-sterile. Therefore at least two different trees are required for pollination. Each avocado flower opens twice. The female part ripens first, then the flower closes to open many hours later in the male stage. In the Mexican form, this gap is more than 24 hours, from morning to the next afternoon, whilst in the Guatemalan it is less than 24 hours. Flowering Time: Mid Spring Late Spring/Early Summer. Bloom Color: Pale Green. Spacing: 20-30 ft. (6-9 m).

Propagation

Sow fresh seed, which can germinate in about a month. Removing the seed coat can reduce germination time to around 17 days. Seedling trees can begin flowering within 5–7 years.

Other Uses

The pulp and seeds contain fatty acids including oleic, lanolic, palmitic, stearic, linoleic, capric, and miristic acid, the last of which constitutes 80% of the fruit's fatty content. Non-drying oil extracted from the seed is used in cosmetic products such as soaps and skin moisturisers. Fresh fruit pulp is massaged into hair and scalp as a vitamin-rich tonic and restorer. A reddish-brown dye obtained from the seed is used for marking clothes. Watery extracts of the leaves contain a yellowish-green essential oil. Ground seed mixed with cheese is used as a rat and mouse poison. The heartwood is light brown and the sapwood whitish; the wood is moderately soft, heavy, brittle, and not durable, and is susceptible to termite attack. It has been used for house building (especially posts), light construction, furniture, cabinetmaking, agricultural implements, carving, sculptures, musical instruments, paddles, pen and brush holders, and novelties, and yields good-quality veneer and plywood.

Production

Seedlings grow quickly and continuously in warm, moist conditions. Seedlings bear after 5-8 years. Grafted trees can fruit in 1-2 years. A good tree produces 400-600 fruit each year. A fruit can weigh 50 g to 1 kg. In the subtropics trees often produce 2 main flushes of fruit per year. From fruit set to maturity can take 6-12 months. Fruit ripen off the tree in 4-14 days. For the Mexican types, the fruit weigh less than 250 g and they ripen 6-8 months after flowering.

Other Information

It is an important fruit tree in many tropical and subtropical countries. It is widely cultivated. The tree and fruit is getting quite wide acceptance at least in the highlands of Papua New Guinea.

Notes

There are about 200 Persea species. Most are in America.

Nutrition

Synonyms

Also Known As

Abacate, Abacateiro, Abokado, Abuacatl, Adpokat, Adpukat, Advokaat, Aguacate, Aguacatillo, Ahuacate, Alan, Alligator pear, Alpuket, Apakado, Aquejora, Aviota, Avocat, Avocatier, Avocato, Avokaa, Avokad, Awokado, Bata, Bo' le dau, Buah apukado, Butter pear, Butter-thei, Divoka, E li, Evokado, Famphale, Htaw-bat-thi, Htaw-bat-thi-pin, Huiy jahaamuguri, Iniak, Kai, Kuka'ta, Kunalhit, Mokotapeni, Mparachichi, Mukorobea, Mwembe mafuta, Palta, Palta muyu, Pohon alpukat, Sikia, Vakedo, You li, Xane yubini cuota

References (143)

• AAK, 1980, Bertanam Pohon Buah-buahan. Penerbitan Yayasan Kanisius, Jogyakarta. p 7
• Abbiw, D.K., 1990, Useful Plants of Ghana. West African uses of wild and cultivated plants. Intermediate Technology Publications and the Royal Botanic Gardens, Kew. p 42
• Alexander, D.M., Scholefield, P.B., Frodsham, A., 1982, Some tree fruits for tropical Australia. CSIRO, Australia. p 9
• Ambasta, S.P. (Ed.), 2000, The Useful Plants of India. CSIR India. p 442
• Anderson, E. F., 1993, Plants and people of the Golden Triangle. Dioscorides Press. p 217

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