Tamarillo: planting & caring for the tree tomato

Tomatoes that grow on a tree? Let us introduce you to the tamarillo. Discover all you need to know about the tree tomato, including how to grow your own and care for it.

Are tree tomatoes a type of tomato? And how are you supposed to eat the fruit? We will answer all these questions and more as we introduce you to this unique plant. We will also give helpful tips on planting and caring for tamarillos, as well as information on how to eat and preserve the fruits of your own tree tomato.

Origin and characteristics of the tree tomato

The fruits of the tamarillo tree (Solanum betaceum) look very similar to tomatoes, which is why it is also called the tree tomato. In fact, the tree tomato, like tomatoes (Solanum lycopersicum), belongs to the nightshade family (Solanaceae). These two species are related, but the tree tomato is not one of the tomato plant species commonly grown in our gardens.

The tamarillo, known as tomate de arbol in Argentina, originally comes from the Andean highlands of South America. This means the plant is adapted to regions close to the equator where temperatures are relatively stable all year round. It is a shrubby, densely branching tree that forms an umbrella-like crown. In its natural habitat, the tree tomato can grow up to six metres tall. The tamarillo is not winter hardy, so in the UK it is usually cultivated in pots, where it reaches a height of about two to three metres. Apart from the fruits that give it its name, the tamarillo has another striking feature, in the form of its leaves. Its oval to heart-shaped leaves grow up to 25 centimetres long and give the tamarillo a decorative appearance even without fruit.

After two years, from June onwards, the tree tomato will begin to form its first flowers. These look quite similar to the flowers of other closely related nightshade plants, such as tomatoes or potatoes (Solanum tuberosum), and are usually pale pink in colour with a pleasantly sweet fragrance. Their egg-shaped fruits are green when growing and turn orange to dark red when ripe, depending on the variety.

Tamarillo species

There are two types of tamarillos available to us in the UK, and they are the Solanum betaceum, also known as the tree tomato, and the Solanum abutiloides, the perennial dwarf tree tomato.

Solanum abutiloides have a slightly misleading name, as the dwarf tree tomato, or dwarf tamarillo, actually grows to be up to two metres high too. Its berries are bright orange and slightly smaller than the berries of the larger tamarillo. The dwarf tree tomato loves warm and moist places and thrives under these conditions. The entire plant, its fruits included, are covered with fine glandular hairs that secrete fungicidal plant substances. This means that Solanum abutiloides can also be used to produce natural sprays against fungal pathogens. During the winter, keep your dwarf tamarillo in a cool place (5-10°C). It loses its foliage during this dormant period, but it will sprout again the following year.

Tip: Tamarillos have been cultivated for centuries in South America and are now also grown commercially in North America and New Zealand, which has led to the breeding of different tree tomato varieties. These varieties differ mainly in the colour and size of their fruits. Unfortunately, as tamarillo cultivation is not very popular in the UK, these varieties of the tree tomato are not yet available.

How to plant and grow tamarillos

As tamarillo trees are not frost-hardy, they need to be moved to a light and frost-free place in winter. So, it makes sense to grow your tamarillo in a pot. The tamarillo prefers a semi-shady to sunny location.

Transplanting young plants is best done in spring, around mid-May, when frosty nights are no longer a risk. It is also possible to grow tamarillos from seed; for this, sow the seeds in compost from April onwards. We recommend using a special seedling soil, such as our Plantura Organic Herb & Seedling Compost. This is less nutrient-rich, which encourages healthy root growth. After placing the tamarillo seeds on the compost, cover them with a thin layer of soil and press down. Keep the soil constantly moist for the next three weeks: putting a plastic cover over the seed tray is a good way to do this. For germination, keep the seeds in a warm, bright place with a temperature of at least 20°C. After about two weeks, the first seedlings should appear. You can prick them out after a few weeks, if necessary, and plant them outdoors after mid-May. The next time you repot, use a more nutrient-rich potting soil.

Because of its speedy growth and high water requirement, a high-quality potting soil is essential for the tamarillo. This soil should be able to store water well and guarantee a good supply of nutrients. It is also a good idea to choose a peat-free soil to avoid environmental damage caused by the extraction of this finite resource. Our Plantura Organic Flower Compost combines all of these key aspects, making it ideal for promoting the flowering and fruiting of your tamarillo.

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How to care for a tamarillo tree

When it comes to tree tomato care, water supply is the key to success. The tamarillo’s leaves are very large, resulting in a lot of water evaporation. For this reason, we recommend that you carry out a daily check to make sure that the root ball is moist enough. However, keep in mind that tamarillos do not tolerate waterlogging well, so avoid this at all costs. A good supply of nutrients is also important for the tamarillo plant, as it grows extremely quickly. A slow-release natural fertiliser, such as our Plantura Liquid Flower Food, is a good option, as it will nourish your tamarillo for up to three months. If you notice an increase in the number of yellow leaves on your tree tomato, our advice would be to shorten the time between each fertilisation, especially during the main growing season, from May to August.

There are not many pests and diseases that affect the tree tomato plant and its fruit. However, tamarillos can suffer from aphid infestations during springtime. For more information on this, we have put together an article detailing how to control aphids naturally. Spider mites can also appear when the tamarillo is in its sheltered winter spot, but they do not usually pose a problem.

There is no need to prune your tree tomato regularly. However, as these trees grow so quickly, they can grow larger than you might like. If this happens, cut back the overhanging shoots. We recommend doing this just before winter.

Summary of how to care for a tamarillo plant:

• Do not allow the root ball to dry out
• To meet high nutrient requirement, fertilise with an organic fertiliser when transplanting
• Prune only when necessary
• Not affected by many pests and diseases
• Not frost-hardy, so overwinter you plant in a bright place where the temperature is above 0°C
• Can be propagated from both seeds and cuttings

Overwintering tamarillo trees

For overwintering, move your tamarillo into its winter location before the weather gets frosty. Since the tamarillo still has leaves left at this point, make sure its winter spot is bright. An optimal temperature is around 10°C, but the tamarillo can easily withstand temperatures as cold as just over 0°C. The tamarillo sheds most of its leaves at this time of year. It is not necessary to fertilise the tamarillo throughout the winter. The root ball should not dry out completely, but regular watering is not usually necessary.

Tree tomato propagation

If your neighbours or friends take a fancy to your tree tomato, you can easily propagate new plants from it. This can be done from seed or cuttings.

To grow a tamarillo plant from seed, save the seeds from ripe fruits. Leave these black seeds to dry for one to two days and then sow in seedling soil.

To propagate from tamarillo cuttings, take a cutting, approximately 20 centimetres in length, with one leaf from a strong and healthy shoot. The optimal time for this is early summer, as this is when the plant grows vigorously, and the cuttings have plenty of time to form roots before winter. Without letting them dry out, put the fresh cuttings into moist potting soil and cover the cuttings with a sheet of cling film that contains a few holes – this prevents them from becoming dehydrated. Place them somewhere dry and shady, and after a few weeks, the cuttings should have formed roots.

How to harvest tamarillos

You can expect the first fruits from the second year of growth. The fruits of the tree tomato ripen in late summer to autumn, depending on the location. When they have taken on their typical orange to dark red colour, and they cave in slightly when pressed, the tasty fruits are ready to harvest.

Tamarillo fruits can weigh up to 100 grams and are divided into seed chambers inside. The tamarillo flesh is yellow-orange in colour.
The fruits of the tamarillo plant do not store well, so it is advised to process them as soon as you harvest them or eat them fresh.

Eating and processing tamarillos

If you want to eat your tamarillo fruits fresh, you can either peel them or cut them in half and spoon out the flesh. The tamarillo’s pulp has a sweet and sour flavour – sprinkle a little sugar on it if you have more of a sweet tooth.
The tree tomato fruits not only taste delicious, they are also very healthy, containing vitamin C, calcium, potassium and magnesium.
Tree tomatoes can also be made into lots of delicious treats. They taste great in the form of spreads; tamarillo jams are packed with flavour. It also goes very well with savoury dishes, as a tamarillo chutney.

If you have a taste for exotic fruits, you should try the gourmet caviar lime. Here, we show you how to grow them in your garden.