Avocados: Pruning flowers boosts production

Phillip West demonstrates flower pruning on Bounty avocados at Lynwood Nursery. Photo / Susan Botting

Flower pruning is boosting returns from mature avocado orchards by $18,000 a hectare.

The flower pruning of excessively flowering trees going into an 'on' cropping year can reduce irregular seasonal bearing by up to 92per cent. Pruned trees then yield more fruit across a two-year period.

New Zealand Avocado research manager Phillip West told an avocado field day at Lynwood Nursery, Maunu, that one flower pruning trial with which he had been involved, showed growers who had flower-pruned mature trees were $18,000 better off per hectare.

The Maunu field day attracted 200 commercial growers from around the North Island.
A relatively new management approach, flower pruning can reduce huge seasonal crop differences: avocado trees can produce big quantities of fruit one season then a much smaller crop the next.

Tauranga-based West said flower pruning helped re-establish consistency between the highs and lows in seasonal fruit production.

He said pruning flowers helped bring the tree into balance and strengthened fruit yields over time.

It balanced a tree's crop load and vegetation as well as the season to season cropping.

He said flower pruning should be done in spring, as early in the season as possible.

Earlier pruning would help the tree instead put its energy into growing vegetation for the production the following year.

Pruning excess flowers was best done at the start of a heavier crop-loading season in the alternating cycle. Whangarei was this year experiencing this with its current 2019 flowering season.

Pruning should begin with careful planning. It should focus on cutting back to a place where there was good leaf or growth. It should be done to a point on the stem where there were stronger healthier mature leaves, or to a place that was growing new vegetation likely to produce flowers the following spring. The amount of flower taken off varied, depending on where it was taken from.

"Don't be shy," West advised growers.

Trials had shown a reduction in yield one year after flower pruning after two years, yields were up.

He said pruners should cut off flower panicles that were exposed or stuck out from leaves. Fruit grown on these panicles would be more likely to get sunburnt.

Trial results on mature avocado trees showed the 2017-18 yield for trees flower-pruned in October 2015 was 923per cent higher than the yield from unpruned control trees.

West said growers tended to be hesitant when it came to taking the flower pruning plunge. Those wanting to begin pruning typically experimented with 10 trees then expanded annually.