Fact Sheet: Avocados
The avocado or Persea americana is not like any other fruit – it’s got high oil content but it isn’t bitter like an olive, it’s got a soft, silky flesh but it isn’t sweet like a banana. A lot of Queenslanders call them an avocado pear, but they are no relation to the pear family.
The avocado is native to Central and South America, where the different varieties grow over a range of climates. This means that in Australia we can grow them anywhere, as long as it doesn’t have heavy frosts.
Peter Young has, for the last 30 years, been growing avocados at Nambour, north of Brisbane. He says that for the home gardener the most important thing is to select the right varieties and the correct cultivar for your growing area.
He suggests a true tropical variety is Walden but southern varieties like the Hazzard will also fruit in the tropics. It’s a regular fruiter, is excellent eating quality and one recommended for the tropics.
Pinkerton is an interesting variety that’s quite adaptable and has the ability to set fruit over a wide range of climatic conditions. And according to Peter, traditional varieties like Hass and Fuerte and Sharwell should be avoided for the average home gardener because they need deep, well-drained soil in excess of 4-5 metres.
They also grow into huge trees – up to 10 -12 metres plus – which is a big disadvantage in backyards. The best selection for the subtropics and warm temperate zones would be Pinkerton, Rincon and Wurtz.
For a cool climate where the temperature doesn’t get below -8 to -10, there’s only one choice and that’s the Baconcultivar. It’s an amazing variety. Its cold hardiness or the anti-freeze, is the anise, or aniseed which contributes to the frost tolerance, and it’s a good indicator in an avocado cultivar.
According to Peter the secret to growing an avocado tree is drainage. If the tree’s root system is fully saturated for 48 hours it will die. He suggests planting into a pot on the patio or in the garden so that the height of the pot is out of the wet.
Get some well-drained potting mix – buy the most expensive one you can – and if you have reasonable soil, then place the pot on the ground and the tree can root into the ground. But at least some of the root system is out of the wet.
Peter leaves the plastic around the avocado and removes it after adding the potting mix so he’s not disturbing the roots. He reckons the tree will grow fantastically and give lots of fruit within two to three years of planting.
Peter likes the 20 per cent rule when it comes to pruning. “Just remove 20 per cent of the vegetative material straight after harvest. Take out one major limb, every year and the tree will be able to stay in the pot indefinitely.”
Avocados are highly nutritious and they produce lots of fruit, so the tree needs to be fed well. Use a complete organic fertiliser, with a bit of extra potash, and add a dusting of a hundred grams per square metre equivalent of gypsum in the spring.
Watering is also important, particularly during heatwaves. Avocados like to have a top-up during the heat of the day.
A lot of people wonder about the right time to harvest an avocado. Wait until the first one falls to the ground, and put that in the cupboard, keep it for about a fortnight to ripen and it’ll be ready to eat. And at that stage you know that you can harvest them from the tree. When the little button at the top starts to change colour and goes a bit lighter, just snip it off, put it in a brown paper bag, put it in the pantry for about a week to a fortnight and it will get soft and it will be magnificent.Information contained in this fact sheet is a summary of material included in the program. If further information is required, please contact your local nursery or garden centre.