Growers Guide for Sumo Orange Tree

  • By: CarlBroadbent
  • Time to read: 7 min.
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There is nothing for satisfying than plucking your ripe citrus fruit from trees in your garden.

It’s even better when it is tantalizingly sweet and flavourful like the amazing Sumo Orange!

If you’re a fan of these quirky mandarins, you may wonder if you could enjoy these delicious fruits on your property.

Growing Sumo oranges
Grower’s guide for Sumo oranges

Technically yes, but this is one of the most challenging citrus varieties to cultivate.

This article will take you through the many trials of growing a Sumo Orange tree!

What is a Sumo Orange?

If you don’t know what the big deal is about Sumo Oranges, you’ve been missing out.

These are a relatively rare citrus variety that is prized for their amazing flavor.

It is a seedless, easy-peeling giant mandarin that has cute squat proportions and a cheeky protruding knob ‌at its stem, known as the top-knot.

What is Sumo orange
Sumo orange explained

These unusual citrus are extremely expensive, running at up to $5 per pound, so you’d save money by being able to grow them yourself.

Right now, Sumo Oranges are only prevalent in the San Joaquin Valley of California and Australia, where they are commercially grown.

But the unique appearance and amazing taste has led to surging demand from growers who want a Sumo Orange tree of their own. 

Why are Sumo Oranges so difficult to grow?

Sumo Oranges are quite unlike any other citrus.

They require insane levels of TLC with commercial growers even applying sunscreen to the developing fruit!

Commercial Sumo orange grower Seth Wollenman explains more…

The trees and their fruit require delicate handling, and in many cases, these trees shut down production with no apparent cause.

So if you are going to grow your Sumo Oranges, you have a challenge on your hands!!

How to grow Sumo Oranges

You need plenty of patience to grow regular citrus varieties, but with Sumo oranges taking up to half a decade to yield their bounty, you’re going to need not just patience but endurance too. 

The principle for growing Sumo oranges and other orange varieties is similar, your first objective is to establish a healthy and maturing tree.

Here are the key methods.

Starting Sumo oranges from seed

Starting a Sumo orange tree from seed is a long shot because these fruits are deliberately bred to be seedless.

The seeds aren’t for sale, so the best way to procure one is to eat these mandarins copiously in the hope that you will bag a few stray seeds.

This has been achieved by many growers who have then gone on to germinate the seed and grow young plants. 

Methods to germinate a prized Sumo seed include placing theed on a moist paper towel in a plastic bag, or sowing directly into a pot with an even mix of perlite and potting soil, watering liberally.

Even if germination is successful, many growers become frustrated by the plant shutting down its growth for no obvious reason.

Transplanting Sumo oranges

They are notoriously expensive but it is possible to buy potted Sumo orange trees, from private growers or specialist nurseries.

Some trees advertised as being “Sumo” are not authentic, as these trees are not common. 

Process of growing sumo oranges
Not easy to grow sumo oranges

If you get your hands on a young potted Sumo orange tree, here’s what to do:

Continue to grow the Sumo orange in pots and containers of increasing size, this is because you will have far more control over its environmental condition, for example, moving the saplings inside for the winter.

They also need fresh soil every couple of years.

Tropical Fruit Tree Grafting: Super...
Tropical Fruit Tree Grafting: Super Easy Way To Do It

Young Sumo orange trees are like newborn babies, they need zero stress so transplanting has to be done with care.

Even if you think you got away with transplanting the tree, it may just decide to pack up!

Only transplant your Sumo orange tree when its stressors are at a minimum. This means undertaking to transplant between mid-Spring and early Fall.

Nice Tip – Remember to keep the soil moist during the hot summer months so the roots are not shocked. The rootball needs very careful and gentle handling, keeping it intact, with some soil, as much as possible. 

Transplanting Sumo orange trees into soil

This is another heart-in-mouth moment, as once your Sumo orange tree is in your yard, you will either have generations of mouthwateringly sweet Sumo oranges or a dud!

Choose your location well!

Evaluate your yard for a location that will provide:

  • Plenty of sunlight: the full sun is ideal, but partial shade is acceptable.
  • Shelter from excessive wind, precipitation, and frost.
  • A nourishing sandy soil with good drainage that the roots of your tree can penetrate.
  • At least 15 feet distant from your home, buildings and other trees s that the roots can spread.

Dig a hole for your Sumo orange tree

Like other orange trees, plant the Sumo orange tree in a hole that is double the size of its rootball, but only half as deep.

This is so that the tree is slightly raised, improving its drainage. 

Use bud wood and graft Sumo orange branches onto an established orange tree

With so many points in growing a Sumo orange tree where it can stop growing, many growers turn to graft Sumo branches onto a reliable citrus tree.

The grafting technique requires patience and skill, but if successful, and the graft is not too fussy you should be able to establish this delicious variety on your property. 

Grafting budwood can be difficult but is not impossible.

This video explains how grafting works…

You can obtain sumo orange budwood (scions) by applying to specialist citrus clonal protection programmes.

Sumo orange tree care tips

For most owners, waiting for Sumo oranges to turn up could take years.

If you are invested in this project for the long haul you’ll need to carefully care for your orange tress just like any other.

Here are some orange tree care tips.

Watering your Sumo orange tree

Recently transplanted trees require frequent watering until they are fully established and adapted to local soils.

Of course, these trees need to develop the resilience to survive dry spells, but deeply watering them once a month (more frequently if your soil is fast draining) through the hottest months can support them.

Feeding your Sumo orange tree

Citrus trees are usually fed with a suitable pellet fertilizer once per season.

Even though Sumo orange trees take time to fruit, take care to fertilize them during the spring and summer when they actively grow. 

Pruning your Sumo orange tree

Pruning will benefit your tree, but it does not need to be extensive if you have a consistent approach.

Citrus trees only require thinning of overcrowded or improperly growing branches.

Here are some general citrus pruning tips that may help you…

When the fruit starts to come through…

It sounds nuts, but the first fruits that your Sumo orange produces need to be promptly picked and discarded.

But when it comes to Sumo oranges you need to take a long view.

This is because you want this tree to spend all its energies on establishing itself for long-term productivity. 

Protect your Sumo orange tree from pests

Remain vigilant for pests and diseases that can deteriorate your Sumo orange tree and spoil its fruit.

Here are some common citrus pests and diseases to look out for.

Citrus black spot (CBS) 

This is a fungal citrus disease caused by the organism Phyllosticta citricarpa.

If a tree becomes infected, it will develop black lesions on its fruit and leaves.

The lesions reduce the quality and quantity of fruit on your tree and often worsen in humid or moist conditions. 

Asian citrus psyllid 

This tiny insect has spread across the US from Florida where it was first detected in the 1990s.

It spreads Huanglongbing (HLB) one of the most serious citrus diseases, that is known for its greening of fruit. 

Grow Healthy sumo oranges
Healthy sumo oranges

Citrus Greening

Citrus greening or Huanglongbing is an incurable citrus tree disease caused by the bacterium Candidatus Liberibacter asiaticus.

An infected tree can be asymptomatic for years before experiencing a noticeable drop in yield and condition.

Along with the greening and dropping of the fruit, the leaves become blotched and mottled.

Once the infection hits the roots, they die back, destroying the tree. 

Sweet Orange Scab (SOS)

Sweet orange scab causes scab-like lesions that mainly affect the fruit, though they remain edible.

It is caused by the fungus, Elsinöe australis.

More serious complications of SOS include premature fruit drop and stunting of young nursery trees.

Harvesting Sumo Oranges

This is the time any grower will have waited for.

It may have taken years, but hopefully, a full and consistent crop of mouthwatering Sumo Oranges will eventually arrive.

Harvest these chunky fruits when they are at their most plump.

Feel them gently to assess their firmness and smell them for that refreshing aroma that lets you know they are ready to eat!

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