South Africa doesn’t have an ideal climate for growing cherries. Herein lies a considerable challenge for those taking on this notoriously finicky crop. But the rewards are worth it for those who succeed, providing a lucrative export market.

For ZZ2, growing cherries in Lanseria, Gauteng, provides an even greater benefit – they are one of only a handful of cherry growers in the global market for four weeks of the year.
“This is a massive advantage,” says Piet van Zyl, general production manager at ZZ2.

“As our cherries enter the market, the Canadian supply has dried up. The next region to enter the market is the Western Cape, followed by Chile in South America, but only six weeks after the last of the Canadian crop.”

Identifying such a niche microclimate like that of the farm Toscana in Lanseria is part of ZZ2’s strategy to ensure the business can grow and position its crops in the market to gain the maximum advantage. While Toscana is far from being an ideal climate for cherries, production is possible with the right management.

“Cherries originated from the highlands of Tibet – you can imagine how cold it gets there,” says Van Zyl. “While temperatures on Toscana can dip to -8°C in winter, they can go up to 34°C in summer. So much of our time is spent on keeping the orchards cool, and manipulating the tree into mimicking behaviour in colder climates.”

The right climate

ZZ2 planted a trial block of cherries on Toscana in 2015. While the results were not as promising as they had hoped, they forged ahead and expanded. Today the farm cultivates 17,4ha consisting of several licensed varieties from Zaiger Genetics – Minnie Royal, Royal Tioga, Royal Letty, Royal Lynn, Royal Alida and Royal Lee – which require fewer cold units than the open varieties.

However, they still need cold, and this requires considerable effort to produce. “We need a minimum of 35 chill portions. Some years we get 35, others 47. But we need to work to keep the cold in the orchards by managing water and airflow through the orchards. We also apply a boron and zinc spray application in winter to force the trees to drop all of their leaves, as they would in colder climates,” explains Van Zyl.

Using the principle of evaporative cooling, the orchards have micro-irrigation suspended above the trees. This water, coupled with the wind that blows through the orchards, helps cool them down.

While the area is prone to frost, this usually arrives when it is not wanted, during flowering, laments Van Zyl.

“The frost will burn off the flowers so we need to bring in a helicopter which flies over the orchards to circulate the air, forcing warmer air from above down into the orchards.”

The helicopter is brought in again during the harvest season, if rain has a high chance of settling on ripe fruit, causing it to burst.

The orchards are liberally irrigated, both to maintain lower temperatures and ensure the fruit does not burst after heavy rain. Temperature probes placed in the trees, and soil moisture probes are used to guide irrigation.

“Right now, with spring temperatures peaking, we need to keep the orchards at a maximum moisture level to maintain a cool microclimate. It also guards against fruit bursting, since dry orchards which suddenly receive heavy rain will slurp up all the water and cause the fruit to burst.”

The trees are planted on ridges to ensure that the roots are not submerged in water.
Nets are erected over the trees to protect the crop against hail.

The farm is also experimenting with rain covers to protect the fruit from rain, which causes the fruit to burst. However they reduce sunlight, causing the cherries to ripen four days later. Van Zyl says reaching the required Brix level of 18 is also more challenging with the rain covers.

Getting into shape

Part of the manipulation of the trees involves guiding the growth of the branches to obtain a tree that conforms to tried and tested norms. This means a tree that is no higher than 3,2m, and which has between 20 and 24 branches.

Van Zyl relates that they reached a stage with the cherries where they realised that there was far more potential in the crop than what they were achieving. They went looking for the best cherry experts in the world, and found them in Chile.

Since implementing the advice of their Chilean consultant, production has improved markedly, pushing up yield, quality and shelf-life.

Van Zyl relates that when he first saw what the cherry trees looked like in Chile, he was shocked. “They looked sick! The trees are so scraggly, compared to our lush trees. But we learnt that severe pruning is needed to shape the tree into a production powerhouse that produces high-quality cherries with a long shelf life. The heavier the fruit load on the tree, the lighter the vegetative growth and vice versa.”

Implementing best practice is however an ongoing effort, since the trees’ structure needs to be changed.

“The pruning required to get to this perfect structure can’t be done in one season or we will not have a crop and an income. We are seeing a lot of success, but we are not where we want to be yet.”

The shaping starts when the trees are still young. As new branches emerge, a toothpick is inserted into the top side of the branch against the trunk, to force the stem to grow down and make a branch that is more horizontal than vertical.

“Everything grows up towards the light, but we want lateral growth. To further force the lateral growth, the branches are tied down using rope. “The rope is adjusted as the tree grows to keep the branches horizontal to the ground. Once the trees reach a point where their branches are set into position, the rope is removed,” explains Van Zyl.

The trees are pruned several times a year. In January, branches are cut back to maintain light in the trees. This prune also ensures that the trees maintain their optimal shape and that a harder prune is not necessary later on in the year.

In July the trees are pruned again to keep the regrowth from the January prune in check.
Foliage is also cut back during the harvest season to ensure that the cherries still on the trees get enough sunlight so that they can ripen optimally.

Light management is particularly important and Van Zyl notes that they are reducing tree density from 1 200 trees per hectare to 880 trees per hectare.

Feeding the orchards

ZZ2 is renowned for its Nature Farming strategy, where soil health takes precedence, reducing synthetic chemical inputs as far as possible. This principle has been applied to the cherries as well.

Between 12m³/ha and 14m³/ha of wood chips are added to the orchards to improve the soil.

Soil analysis is done annually and nutrients balanced organically and chemically. Van Zyl notes that by focusing on soil health, they are gradually improving the soil and reducing the need for nitrogen applications. The latter have gone from 78kg/ha when the first trees were in full production to 36kg/ha today.

Protecting cherries against pests and diseases is challenging in South Africa since the relative small size of the national crop means few crop protection companies are willing to go to the effort and expense to register products. This means that Van Zyl has to rely on preventative controls and natural remedies.

Cherries’ biggest pests are thrips, bollworm and red spider mite. Natural predators are used to control the latter. Bait stations are placed in the orchard to keep fruit fly at bay.
An optimal tree structure also aids in pest control, since spray applications have a far higher chance of hitting the target if the tree is not overgrown and dense.

Preventative control also means removing any plant material that could provide a breeding ground for pests. Flowers and fruit that are thinned out, and any prunings are immediately removed from the orchard and buried in a hole at least 1m below the ground surface. Any fruit that is discarded from the packhouse is also buried.

Van Zyl notes that if the orchards are in optimal condition – having the right tree structure, light management, pest control and nutrition – cherries’ shelf life is extended and ZZ2 can maintain optimal quality until the fruit reaches the consumer.

“As soon as fruit is picked it effectively starts decomposing. Cherries are not like tomatoes that can be picked green and then ripen, providing an extended shelf life. Cherries are picked when they are optimally ripe so they need to get to the consumer as soon as possible – 72 hours for the export market and 48 hours for the local market. There are things you can do to ensure the fruit maintains good quality for longer, and this is what we focus on.”

Part of this recipe entails applying amino acids, which aids the tree in absorbing nutrients. “If for example, we need to do a calcium application, we will add amino acids so that the trees will fully absorb the calcium dose.”

The right nutrition has also helped and ZZ2 is reducing the number of times an orchard needs to be harvested. Previously, workers would need to go through the orchards at least six times during the six-week harvest season to select only ripe fruit.

Since gaining insight from the Chileans, this has been reduced to two. “We apply a mix of amino acids, phosphate and potassium, which ensures a more uniform ripening and colouring of the fruit.

“Since labour costs are one of your biggest expenses, the reduction in harvesting sessions has reduced our labour costs.”

Size matters

Cherries reach full production in year seven, with around 10% of the full harvest achieved in year three. While yields can exceed 20t/ha, Van Zyl notes that volume is attained at the expense of size and quality. They therefore aim for a yield of 12t/ha, to achieve an export rate of 90%.

“The biggest factor with exports is size. If the cherries are not sufficiently big, they can’t be exported and are sent to the local market. This is why flowers and fruit are thinned out to balance yield, size and quality,” says Van Zyl.

For the market in the Middle East, cherries need to be at least 26mm in diameter. The UK will take cherries of at least 24mm in diameter.

The fruit is picked and taken to an on-farm cooling facility, where it is chilled to 4°C before being packed and airfreighted to export markets.

South Africa is a small player in the global cherry market. The national crop does not exceed 10 000t, compared to the 460 000t produced by Chile annually. Still, there is much scope for growth both in terms of local production and expanding international markets.

ZZ2 is eagerly awaiting the opening of the Chinese market for South African cherries, which should take place in 2026. This will provide them with a lucrative market where cherries are highly sought after, still keeping them in the six-week window where no other cherries are available in the market.

“The export market is healthy and prices are good. Of course the exchange rate helps us a lot too,” says Van Zyl.

“So I think there is a lot of scope for growth. But it is critical that producers find the right microclimate and put in the required effort.

There is no one thing you need to do to succeed with cherries – it’s a constant process of tweaking the trees, learning how to do things better and finding the best and latest research and technology to apply.”

He adds that ZZ2 is planning on expanding production on the Toscana farm.

Armed with a far better understanding of growing this finicky crop, and having honed their skills over the last nine years, they are poised to meet the demand for this luscious fruit in a period of the year when no other growing region in the world can.

Email Francois Schwalb at [email protected].