By planting several different varieties you will not only increase the flower pollination with better fruit set, but you will also have fruit throughout many months of the year as they ripen at different times.
Correct site selection is the biggest influencer of the success or failure when growing avocado trees.
They grow best in a warm situation with fertile, well drained soil in full sun and need protection from both strong winds and frost while the plants are young.
Once they are established the trees can withstand frost to -2C or -3C and are in fact relatively salt hardy.
Avocado trees need a good sized area to grow, if left to their own devices they will eventually (after about 15-20 years) grow to a tree of approximately 10-12 metres high and 4-6 metres wide.
For those who are keen, avocado trees grow easily from seed but the downfall is they will take up to 10 years to fruit.
Trees that are grafted will produce fruit after approximately four years and after seven years should be producing 200 or more avocados annually.
Many homes do not have a spot large enough to have a tree of this size but by pruning each year a much smaller tree can be maintained.
There is much information online about growing avocado trees in pots; the pot will help restrict the size of the tree.
Similar to growing citrus and other trees in pots, it will grow successfully if it is given all the water and nutrient that it requires, even if it gets pot bound, and will produce a yield, although this will be less that a tree that is allowed to fully grow unrestricted in the garden.
One variety recommended for growing in pots is avocado Reed.
Pollination
Avocado trees have an interesting arrangement with their flowering and have been classified into 'A' type and 'B' type tree varieties. The trees have both male and female flowers on the tree.
'A' Type Flowering Pattern (Hass & Reed)
The female opens in the morning of the first day for two to three hours and then closes.
The male flower opens in the afternoon of the second day for two to three hours then closes.
Cross pollination of two varieties helps in the warmer climates.
In the cooler climates opening and closing of the flower tends to overlap therefore making them more self-fertile.
Cross pollination should be from a 'B' type flowering variety such as - Hashimoto, Bacon or Fuerte.
'B' Type Flowering Pattern (Bacon, Fuerte & Hashimoto)
The female part opens in the afternoon on the first day for two to three hours then closes.
The male part opens the morning of the second day.
During cooler weather the flowering can be delayed and quite erratic.
This can mean the opening and closing of the male and female flowering can overlap, increasing rates of self pollination.
When the temperatures are warm and reach 21C or above the flowering becomes much more regular.
To summarise, all varieties are self fertile but the weather conditions will make a significant part to the amount of fruit set.
If you have issues with fruit setting then planting planting a mixture of both 'A' and 'B' flowering types will increase the pollination.
Varieties
* Hass - New Zealand's favorite avocado, crocodile skinned tasty fruit, heavy cropper. Fruit mature from September to March, 'A' type flowering pattern, cross pollinated by Fuerte or Bacon.
* Reed - Large cannon ball fruit, heavy cropper and very nutty flesh. Fruit mature from February to June, 'A' type flowering pattern, cross pollinated by Hashimoto, Fuerte and Bacon.
* Fuerte - Very vigorous green skin avocado with some cold tolerance. Fruit mature from September to December, 'B' type flowering pattern, cross pollinated by Hass and Reed.
* Bacon - A smooth skinned green avocado, with fruit maturing July to September, 'B' type flowering pattern, cross pollinated by Hass and Reed.
* Hashimoto - Very vigorous green skin avocado with some cold tolerance. Fruit mature June and July, 'B' type flowering pattern, cross pollinated by Hass and Reed.
There is good range of avocado trees available at the moment, so why not give one as a Christmas present?
- Gareth Carter is general manager of Springvale Garden Centre.
