Avocado – Persea americana
Contributed by Linda
The avocado is an evergreen tree which grows to 6-8 m with a spread of 4-6 m and has a life span of 25-30 years. The fruit are rich in monounsaturated fats and so help maintain the level of ‘good’ HDL cholesterol. They also have high levels of the antioxidant Vitamin E.
Types of Avocadoes
Avocadoes can be divided into the Guatemalan and the Mexican types: the Guatemalan bear larger fruit and are more sensitive to cold; the Mexican varieties have smaller fruit and can withstand temperatures as far down as -4°C. Avocadoes cross-pollinate with other avocado trees and these trees bear both male and female flowers. Usually, the male and female flowers are present at the same time so self-pollination occurs. To ensure a good crop plant two avocado trees, one of each variety A and B.
|Variety A||Variety B|
a large up-right tree bearing medium-sized fruit with thick blackish
wrinkled skin. Good crops from mid-summer to autumn.
|Fuerte – a large spreading
tree with green, smooth -skinned pear-shaped fruit. Summer fruiting.
medium to large round fruit with green skin. Fruit is smooth-textured
with a buttery taste. Mid-summer to autumn harvest.
|Zutano – up-right tree
bearing medium-sized pear-shaped fruit. Fruit has a large stone. Late
summer to autumn harvest.
dwarf variety. Can be grown in a pot and produces delicious green pear-shaped
fruit on weeping branches.
|Bacon – quick growing,
cold tolerant and bear fruit at an early age. The thin skin is
prone to fruit fly attack.
Commercial ripening times
Home-growers can extend these times by at least 3 months, either way.
|May||Jalna, Zutano, bacon|
|June||Zutano, bacon, fuerte|
|July||Zutano, bacon, fuerte, rincon|
|August||Fuerte, rincon, edranol, sharwill|
|September||Fuerte, rincon, edranol, sharwill,
hazzard, hass, millicent
|October||rincon, edranol, sharwill,
|November||hazzard, sharwill, hass, millicent,
|December||Hazzard, hass, millicent,
Avocado trees are shallowing rooting. They grow well in rich loamy free-draining soil, slightly acidic (pH 6.0-6.5).
Cold, damp conditions in winter can lead to root rot.
The trees are intolerant of wind (when young) and need a sheltered micro-climate.
In the first year of growth, the trees need protection from strong sunlight. A Hessian shelter is advised until the tree is above your height.
In cold areas, plant avocadoes against a north-facing wall.
Do not mulch the tree in winter and grow herbs and small plants around the trunk.
Avocadoes like plenty of nitrogen so pelletised chook manure is ideal from early summer.
Avocadoes will grow from seeds (they sprout easily) but they will not fruit for about 10 years. Avocadoes will thrive where ever camellias will grow and they form a good hedge in much less time.
Note that the fruit take up to 12 months to ripen so both fruit and flowers can be present at the same time.
Avocadoes do not ripen until you pick them or they fall from the tree. Harvesting can begin when the fruit are about the size of an apricot.
Clip the fruit from the tree leaving a short stem.
Hass avocadoes stay on the tree the longest (November to April) but if you leave the mature fruit on the tree for too long there is the danger that your tree will become biennial bearing.
Pruning and training
Avocadoes grown naturally into large trees so you should prune your tree back to 2-3m each year. Large trees can be pruned back to a few branches which will re-sprout from dormant buds. Fruiting may then take a few years to occur. Pinching out new growth is best and keep the centre of the tree open to discourage fungal disease. Prune for shape after the fruit has set.
Note that dwarf varieties are now available at some nurseries.