Brisbane tree guide

Avocado tree

Persea americana · also called Avocado, Avocado pear, Alligator pear

An avocado tree is an evergreen fruit tree from Mexico and Central America, and a grafted one can start bearing in its second or third year. It needs deep, free-draining soil, because its roots are very prone to Phytophthora root rot, plus shelter from strong wind. Left unpruned it can reach about 15 metres, and parts of the plant are poisonous to birds, dogs and livestock.

Exotic
6 to 15 m tall

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Avocado tree, from Wikimedia Commons — Photo: B.navez, CC BY-SA 3.0, via Wikimedia Commons

Avocado tree at a glance

Height: 6 to 15 m (up to 20 m in the wild)
Leaves: Evergreen
Flowers: Small and easy to miss
Origin: Mexico and Central America
Family: Lauraceae

How to identify an avocado tree

An evergreen tree that can reach about 15 metres if left unpruned. The leaves are large and leathery, 10 to 30 cm long, glossy dark green on top and bluish-grey underneath, with strong veins, and young growth is covered in flat, whitish hairs. Small yellowish-green or cream flowers appear in branched clusters near the shoot tips. The fruit is pear-shaped to round, 7 to 15 cm long, usually dark green but purple to black in some varieties, with one large round seed. Most garden trees are grafted varieties such as Hass, Reed or Wurtz.

Growing an avocado tree in Brisbane

Avocados prefer frost-free sites, and they need about four weeks of cool weather in autumn and winter before they will flower. Drainage matters most: they can't cope with heavy or soggy soil, and Phytophthora root rot, the most destructive avocado disease, thrives in wet ground. Plant on a mound in deep, free-draining soil, away from windy spots. Business Queensland says watering is essential in most of the state from August to April, but overwatering also feeds root rot.

What to watch out for

Parts of the plant contain persin, a toxin that can poison birds, dogs, horses, rabbits and livestock, so keep pet birds and stock away from leaves and fallen fruit. Some people are allergic to the pollen or fruit. Avocado is a host of Queensland fruit fly, so clear fallen fruit. Root rot can kill a tree slowly, starting with pale, wilting leaves and dieback from the shoot tips. Queensland's WildNet database records it as naturalised and flags it as an environmental weed; escapes mostly come from discarded seed.

Poisonous parts. Parts of the plant, including the leaves and seed, contain persin, which is poisonous to birds, dogs, horses, rabbits, livestock and fish.
Allergies. Some people have allergic reactions to avocado pollen or fruit.
Falling fruit. Avocado is a host of Queensland fruit fly, and Business Queensland advises not letting fallen fruit build up under trees.
Dropping limbs. Strong wind can break limbs and scar fruit, so Business Queensland advises avoiding windy sites.

Pruning and care

Prune after harvest, in autumn or winter. Pruning early in autumn while it is still hot can trigger a burst of regrowth, and pruning just before hot spring weather can leave newly exposed limbs sunburnt. Aim to keep the tree to a size you can pick and let light into the canopy: spreading types like Hass respond to removing one major limb a year, while upright types such as Reed may need topping every two or three years. Keep mulch off the trunk and avoid both overwatering and drought stress.

Avocado tree: your questions

Short answers, from the sources below.

Back to the tree guide

How long does an avocado tree take to fruit?

A grafted avocado tree may start bearing in its second year, with bigger crops usually from the third year. Business Queensland recommends buying from an accredited nursery so trees start free of root rot.

Why is my avocado tree dying?

The usual suspect is Phytophthora root rot, the most destructive avocado disease. Look for pale, wilting leaves, dieback from the shoot tips and few, blackened feeder roots, especially in wet or poorly drained soil.

Are avocado leaves poisonous to dogs and birds?

Yes. Avocado contains a toxin called persin, and Flora of Australia lists birds, dogs, horses, rabbits, livestock and fish among the animals it can poison.

Do you need two avocado trees to get fruit?

Usually not. Business Queensland says single-variety plantings set fruit well in most of eastern Australia, though in cooler areas growing an A-type and a B-type variety together can help in some years.