Sour Orange Tree: Everything You Need to Know

Sour orange trees are a type of citrus tree that is known for its tart, acidic fruit. It is also known as “bitter orange” or “Seville orange”. The scientific name for the sour orange tree is Citrus aurantium.

Sour orange trees are medium-sized, and they have a more compact crown than sweet orange trees.

The bark of the sour orange tree is smooth and dark gray-brown, and the young twigs are green and angular. The tree has sharp thorns that can grow up to two inches long on the branches.

Sour orange trees feature aromatic, alternating leaflets that are delicately serrated along the edges and have broad-winged petioles.

The tree’s fragrant white flowers appear alone or in small clusters. One of the tree’s most distinctive characteristics is its round or oval, rough-surfaced fruit that has an aromatic and very bitter skin.

The fruit’s color is a vibrant red-orange with sunken oil glands when it is fully ripe.

sour oranges on tree

The internal flesh consists of ten to twelve segments. During ripening, the fruit’s center hollows out. Sour orange trees can reach a height of 20-30 feet and live for more than 50 years.

The origin of the Sour oranges

The origins of the sour orange tree are disputed. Some believe that it is a natural hybrid of two other citrus species, while others believe it was cultivated as a hybrid by humans.

Botanists believe Citrus Aurantium (sour orange) and Citrus Sinensis (sweet orange) are botanical species but not cultivated varieties of the same species.

The sour orange tree is thought to have originated in China or Southeast Asia and was later introduced to the Mediterranean region.

Although the exact geographical origin of the sour orange tree is unknown, it made its way to Europe during the Middle Ages. Later, in the 16th century, Spanish explorers introduced it to North America.

Where does the Sour Orange tree grow best?

The sour orange tree grows best in tropical and subtropical climates. It thrives in USDA hardiness zones 9 through 11. Although the tree prefers full sun it is tolerant of some shade.

Sour orange trees are more resistant to cold than sweet orange trees. However, as they are another citrus tree, they are also susceptible to damage from frost. Therefore, they should be kept from freezing temperatures.

Long periods of cold weather can harm the tree’s flowers and fruit. Therefore, if you live in an area with cold winters, it is best to grow your tree in a pot. So that you can bring it inside when the weather gets too cold.

What types of soils does the Sour Orange tree grow best in?

The sour orange tree tolerates a wide range of soils, including sandy, loamy, and clay soils. However, it grows best in well-drained sandy soils with a pH between 6 – 7.

The tree does not tolerate wet or waterlogged soils. If the soil is too heavy, it will compact and suffocate the roots, causing the tree to die. Therefore, it is important to plant your tree in a way that allows the roots to breathe.

Here are a few practical soil mixes that you can use for your sour orange tree:

  • One part peat moss & two parts perlite & one part sand
  • One part coconut coir fiber & one part peat moss & one part perlite
  • One part compost & one part sand & one part perlite
  • One part pine needles & one part sand & one part compost

The reason we want to include materials like perlite, coir fiber, and pine needles in our soil mixes is that they improve drainage and aeration. This is exactly what the roots of your tree need to stay healthy.

You can also try combining other alternatives like lead mold, or rice hulls as long as they fit the bill in terms of drainage and aeration.

Most plants including the Sour Orange tree cannot do well in salty soils. If you live in an area with salty soils, you will need to leach the salt out of the soil before planting your tree.

The coastal areas are the most common places where salty soils occur. This is because of the high content of sodium in seawater which gets deposited on the soil over time.

To leach the salt out of the soil, you should start with a soil test. This will give you an idea of the salt content in your soil. If the salt content is high, then you can do the necessary amendment to make the soil more conducive to plant growth.

How much water does the Sour Orange tree need?

The Sour Orange tree is drought-tolerant and can survive long periods without water. However, it grows best with regular watering, especially during its establishment phase.

Once the tree is established, it can survive on rainfall alone. However, during periods of prolonged drought, you should water your tree to prevent it from stress.

Here is a watering schedule that you can follow for your Sour Orange tree:

Watering during the establishment period

The establishment period takes place from when the tree is planted until it becomes fully grown. It is typically the first few years after planting. During this time, you should water your tree regularly.

The frequency will depend on the weather and the type of soil you have. In general, you should water your tree once a week.

However, during hot weather or if you have sandy soil, you may need to water your tree more often. In this case, you can water your tree twice a week.

Typically, you should water your tree early in the morning when the evaporation rate is low. This will ensure that most of the water goes to the roots where it is needed.

If you don’t have any guidance on how much water to give, you can start with around 1/2 gallons at a time. Obviously, this number doesn’t take into account the season and the type of soil you have.

Try to water the roots at the base of the tree at a slow and steady rate. This will allow the roots to absorb the water more effectively.

Remember the above watering amount is given considering your tree isn’t planted in a pot. A pot is restricted space and it will not easily allow the draining of water. Therefore, if your tree isn’t planted on the ground, you should have half the watering amount which is around a quarter gallon.

It’s always better to err on the side of too little water rather than too much. When in doubt, it’s better to underwater your tree than overwater it.

Watering during drought periods

As we mentioned earlier, the Sour Orange tree is quite drought-tolerant and can survive without water for long periods of time.

That being said, during prolonged periods of drought, you should water your tree to prevent it from stress. The frequency will depend on the severity of the drought and the type of soil you have.

In general, you should water your tree once every two weeks. However, if the drought is severe or if you have sandy soil, you may need to water your tree more often. In this case, you can water your tree once a week.

As with watering during the establishment period, try to water the roots at the base of the tree at a slow and steady rate.

If your tree is already mature, you don’t need to water it as often. Watering every other week should be sufficient.

Please note that, if there has been recent rainfall, you may also not need to water your tree at all. It’s always best to check the soil before watering to see if it is still dry.

How to fertilize the Sour Orange tree?

The Sour Orange tree is not a heavy feeder and doesn’t require a lot of fertilizer. In fact, too much fertilizer can actually harm your tree.

As with most things, it’s always best to start with a little and then increase the amount as needed. Fertilizing once a year should be sufficient.

The best time to fertilize your tree is in the spring, just before new growth begins. This will give your tree the nutrients it needs to grow healthy and strong.

You can use any type of fertilizer for your Sour Orange tree. However, we recommend using an organic fertilizer that is low in nitrogen. This will prevent your tree from getting too much nitrogen, which can be harmful.

You can apply the fertilizer either directly to the soil or through foliar feeding. Foliar feeding is when you spray the leaves of your tree with a diluted solution of fertilizer.

This method is especially effective in hot weather when the soil is dry and the roots are not able to absorb nutrients as effectively.

However, if you will follow traditional methods of applying fertilizer to the soil, make sure you are using a granular fertilizer that is designed to be slowly released.

This will prevent the roots from getting too much fertilizer at once, which can harm your tree.

If you don’t want to use chemical fertilizer, you can use compost or manure. Just make sure the manure is fully composted before using it on your tree.

You don’t want to add too much nitrogen to the soil, which can be harmful. As always, when in doubt, it’s better to err on the side of too little fertilizer rather than too much.

Should you prune the Sour Orange tree?

The Sour Orange tree is a low-maintenance tree and doesn’t require a lot of pruning. In fact, pruning too much can actually harm your tree. Because pruning stimulates new growth, it can cause your tree to use up more energy than it has.

Pruning is only necessary if you want to shape your tree or remove damaged or diseased branches.

If you do need to prune your tree, the best time to do it is in the late winter or early spring. This will give your tree time to heal before the growing season begins.

When pruning, always cut branches back to a healthy bud or branch. By doing this, you will encourage new growth that is strong and healthy.

Here are important pruning tips you should follow:

  • Always use clean, sharp pruning tools. This will prevent infection and disease.
  • Make sure to sterilize your pruning tools before each use. You can do this by dipping them in a solution of bleach and water.
  • When cutting branches, always make sure the cut is at a 45-degree angle. This will help the wound heal quickly.
  • Never remove more than one-third of the branches from your tree at one time. This can shock your tree and cause it to go into decline.
  • Immediately after pruning, apply a wound dressing to the cuts. This will help prevent infection and disease.

What are the pests and diseases that affect the Sour Orange tree?

The Sour Orange tree is relatively resistant to pests and diseases. However, there are a few that can cause problems for your tree. These include:


These small, pear-shaped insects can be found on the underside of leaves. Aphids suck the sap from leaves and can cause them to turn yellow and curl.

To get rid of aphids, you can either use an insecticide or wash them off with a strong stream of water.


These pests look like small, white balls of cotton and can be found on the stems and leaves of your tree. Mealybugs suck the sap from plants and can cause them to wilt and die.

Getting read of mealybugs can be difficult, but you can try using an insecticide. You can also remove them by hand using a cotton swab dipped in rubbing alcohol.

Scale Insects

Scale insects are small, hard-shelled pests that attach themselves to the stems and leaves of plants. They suck the sap from plants, which can cause leaves to turn yellow and drop off.

To get rid of scale insects, you can use an insecticide or remove them by hand. To remove them by hand, you will need to scrape them off with a sharp knife.

The uses of Sour Oranges

Sour oranges are a versatile fruit that can be used in many different ways. Whether you’re using the fruit, the peel, or the juice, there are a variety of ways to incorporate sour oranges into your life.

Sour oranges are mainly grown primarily for flavorings, marmalades, and fragrances, rather than for eating fresh. There are also other minor traditional uses, such as in certain Chinese and Ayurvedic medicinal preparations.

The oil from the peel is used as a flavoring in foods and beverages, as well as in fragrance production. The juice of sour oranges is too acidic to be consumed as is, but it can be used as a meat tenderizer or added to marinades.

The essential oil of the sour orange is used in the production of perfume and household cleaners. It is also a component of many cosmetics, such as lotions, soaps, and shampoos.

Sour orange trees are also used as rootstock for sweet oranges and other citrus trees. The hardy nature of the sour orange tree makes it ideal for this purpose.