Gareth Carter: Growing your own avocados is rewarding

Plant your own avocado tree and reap the rewards. Photo / File

COMMENT

The avocado has become a national topic of conversation. The conversations have ranged from media articles touting that the eating of the avocado stack is the reason fewer millennials own their own homes, to reporting of the theft of fruit from orchards.

There are plenty of stories of the high prices this fruit hits during certain times of the year. They have become a hot commodity, with pricing varying wildly through the year, and they are still far more expensive than, say, apples or bananas.

The reporting of health benefits in the media has also driven avocado popularity. They are rich in mono-unsaturated oil, proteins, vitamins A and B, while being low in cholesterol and sugar and contain a large amount of minerals.

In the garden centres we have experienced the popularity of this fruit in tree sales, as gardeners and non-gardeners alike recognise the economic value. There is also the satisfaction that can be gained from simply planting an avocado tree of their own and reaping the rewards.

As a garden centre, we have to order many of our avocado trees 12-36 months in advance. This crystal ball gazing is helpful to some extent but has been hampered by continued increasing demand and the unpredictability of nursery crop failures and growing conditions.

So, how easy is it to grow an avocado?

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 about 10-12m high and 4-6m 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 about four years, and after seven years should produce 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. Intensive planting and pruning is now being practised by new commercial plantings where traditional tree spacing of 10m apart is now being halved to about 5m apart. Skilled pruning keeps trees maintained at 3-4m high, while not removing the trees' ability to fruit. This means fruit production is much closer to the ground, reducing the labour needed at harvest time. The high labour input to extract fruit from tall trees is one of the contributing factors to the high cost of avocados relative to other fruits.

Many people know the avocado varieties Hass and, to a lesser extent, Reed which are sold throughout New Zealand. There are other varieties that should also be considered for the home garden. 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 the varieties ripen at different times.

The 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 cannonball fruit, heavy cropper, very nutty flesh. Fruit mature from February to June. "A" type flowering pattern. Cross-pollinated by Hashimoto, Fuerte and Bacon.
Fuerte: Very vigorous green-skinned avocado with some cold tolerance. Fruit mature from September to December. "B" type flowering pattern. Cross-pollinated by Hass or Reed.
Bacon: A smooth-skinned green avocado, with fruit maturing July to September. "B" type flowering pattern. Cross pollinated by Hass or Reed.
Hashimoto: Very vigorous green-skinned avocado with some cold tolerance. Fruit mature June and July. "B" type flowering pattern. Cross-pollinated by Hass or Reed.

Pollination
Avocado trees have been classified into "A" and "B" type varieties for their flowering pattern. The trees have both male and female flowers on the tree.

"A" type (Hass and Reed): The female opens in the morning 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. This means cross-pollination of two varieties helps in the warmer climates. In the cooler climates, opening and closing of the flower tends to overlap, making them more self-fertile. Cross pollination should be from a "B" type flowering variety such as Hashimoto, Cleopatra, Bacon or Fuerte.

"B" type (Bacon, Fuerte and 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. Cross-pollination with an "A" type helps in warmer climates and they are more self-fertile in cooler climates.

During cooler weather, the flowering can be delayed and quite erratic. 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.

All varieties are self-fertile but weather conditions play a significant part in the amount of fruit set. If you have issues with fruit setting, planting a mixture of "A" and "B" flowering types will increase pollination.

There is a good range of avocado trees available in limited numbers at the moment - why not treat yourself or give one as a Christmas present?

Gareth Carter is general manager of Springvale Garden Centre.