Avocado trees that are grafted will produce fruit after about four years and after seven years should produce 200 or more avocados annually.
Gareth Carter is the general manager of Springvale Garden Centre in Whanganui.
OPINION
Warm summer weather is a good time to make plantings and establish cold-sensitive fruiting plants.
Yes, you will need to water them during the summer months but getting good growth on them before winter is key to survival for some, such as tamarillo, banana, taro, ginger, turmeric, cassana, pawpaw and avocado. Site selection will be key — it needs to be warm and frost-free for these more tropical plants.
The avocado, which is today’s topic, can withstand frost to -2C or -3C once the tree is established.
Avocados have been recognised for their health benefits as well as a wide range of meal and snack options. They are rich in mono-unsaturated oil, proteins, and vitamins A and B, while being low in cholesterol and sugar, and they contain a large amount of minerals.
Correct site selection is the biggest influencer of success when growing avocado trees. They grow best in a warm situation with fertile, well-drained soil in full sun and need protection from strong winds and frost while the plants are young.
Avocado trees need a good-sized area to grow. If left to their own devices, they will eventually (after about 15-20 years) grow 10-12 metres high and 4-6m wide.
For those who are keen, avocado trees grow easily from seed but the downside 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. Skilled pruning is undertaken to keep trees maintained at 3-4m high, while not removing the trees’ ability to fruit. This means fruit production is far closer to the ground, reducing the labour needed at harvest. The high labour input to extract fruit from tall trees is a contributing factor 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 also have fruit throughout many months of the year as the varieties ripen at different times.
Hass: NZ’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 and very nutty flesh; fruit mature from February to June; A-type flowering pattern; cross-pollinated by Hashimoto, Fuerte and Bacon.
Fuerte: Vigorous green skin 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; fruit mature July to September; B-type flowering pattern; cross-pollinated by Hass or Reed.
Zutano: More cold-hardy than Hass; earliest to fruit, ripening in July and August; fruit has fibrous texture with higher water content and lower fat/oil content; yields well with thin-skinned, pear-shaped fruit resembling Fuerte; B-type flowering pattern.
Sharwil: Creamy with a mild rich flavour, not as nutty as Hass; oval fruit similar to Fuerte; skin is hard; a major commercial variety in Hawaii due to its high quality and exceptional flavour and a smaller stone; fruits for a long time starting before Hass about August and overlaps with Reed into February; B-type flowering pattern.
Cleopatra: Medium-sized pear-shaped black fruit with a shiny skin; yellow creamy flesh with creamy rich flavour; skin turns black before harvest; larger than Hass fruit; harvest from July to December; dwarf tree about 3m high by 3m wide and compact and bushy in habit; B-type flowering; cross-pollination with Hass and Reed will improve fruit set.
Avocado trees have an interesting flowering habit. Avocados 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 and 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. Hence cross-pollination of two varieties helps in warmer climates. In 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, Bacon, Ettinger, Sharwil, Zutano or Fuerte.
B-type flowering pattern (Bacon, Sharwil, Zutano, Cleopatra and Fuerte): The female part opens in the afternoon on the first day for two to three hours then closes. The male part opens on the morning of the second day. Again, cross-pollination helps in warmer climates. Cross-pollinate using A-type flowering variety — Hass or Reed.
During cooler weather, the flowering can be delayed and quite erratic. This can mean the opening and closing of the male and female flowers overlap, increasing rates of self-pollination. When the temperatures are warm and reach 21C or above, the flowering becomes much more regular.
So all varieties are somewhat self-fertile but the weather conditions will 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 the pollination.
There is a good range of avocado trees available at the moment. Why not treat yourself — remember the saying “the best time to plant a tree was 10 years ago, the next best time is today”.
For more gardening information visit springvalegardencentre.co.nz.