How to Plant and Grow a Tree Tomato (Tamarillo)

When you see a fruit similar in size to a small tomato but with orange flesh and lots of seeds, you've happened upon a tamarillo. Because the fruits closely resemble a tomato, it's also referred to as a tree tomato plant (Solanum betaceum). A native to Central and South America, this shrubby plant is part of the nightshade family like tomatoes and peppers. Here's what you need to know to grow your own tree tomato and enjoy the unique fruits.

Where to Plant Tree Tomato

Tamarillo thrives in hot USDA Zones 10–11 climates. It is a hardy shrub or tree that can be planted directly in the ground or in a pot. Choose a location that receives around six to eight hours of direct sunlight. Tree tomato also benefit from partial shade, particularly in the afternoon, in the hottest regions.

When choosing the ideal spot, consider how much wind the area receives. Because these shrubs have a shallow root system, they need protection from strong winds that could blow over the plants.  

How and When to Plant Tree Tomato

Tree tomatoes can be grown from seed, but if you want a head start, buy a seedling. The best time to plant a starter plant is after the last frost in spring. Remove the seedling from the nursery container and plant it at the same depth in the garden or container. If you're planting multiple shrubs in the landscape, space them 2-3 feet apart, leaving 6 feet of space between multiple rows. 

Tree Tomato Care Tips

Tamarillos are large shrubs that are easy to grow as long as you provide the care they need. 

Light

Tree tomatoes thrive in full sun. If you live in a tropical region or a hot climate, plant the tree tomato in partial shade. 

Soil and Water

Tree tomatoes do best in well-drained soil that is enriched with organic matter. Provide adequate water to keep the soil moist but not soggy. Because this plant has shallow roots, it needs to be watered frequently. The best time to water is early in the morning before the heat of the day. When watering, keep the foliage dry; wet foliage leads to fungal diseases. Mulching can be beneficial to retain moisture in the soil. Tree tomatoes don't do well in droughts or long periods without water. 

Temperature and Humidity

This subtropical plant grows best in warm climates. The optimum humidity for these plants is 90–95%. Typically, temperatures that don't go below 50°F are ideal, but these trees can manage in regions where temperatures go as low as 28°F with protection, although they may not grow as well. If you live in a climate with cold winters, grow a tree tomato in a large container and bring it inside your home or a garage until spring returns. 

Fertilizer

Fertilizer is usually unnecessary, especially if you planted the tree tomato in rich soil with plenty of organic matter. However, you may want to apply a liquid fertilizer to give the plant an extra boost during the growing season when it's flowering or producing fruits.

Pruning

Pruning a tamarillo can help with fruit production. Pruning long stems and pinching back young shoots results in compact growth and encourages fruit to grow closer to the center of the plant. Prune tamarillo once a year right before winter.   

Potting and Repotting Tree Tomato

Gardeners who live in cold growing zones that experience heavy frosts and freezes will need to grow a tree tomato in a large, well-draining container filled with high-quality potting soil. Bring the container into a sheltered area such as a garage for the winter. While the container is outdoors, the plant needs additional water, as container soil dries out quicker than garden bed soil. Tree tomato plants are fast growers that soon require larger containers. When repotting, look for wheeled containers to make relocating the plant easier.

Pests and Problems

Tamarillos are susceptible to some of the same pests you might find on your tomato plants. Be on the lookout for hornworms, which feast on tomato plants and other plants from the nightshade family. Picking off these hornworms by hand is usually sufficient, but stay vigilant as these caterpillars are known to devour plants rapidly. 

Aphids and fruit flies can occasionally attack tamarillos. Treating the plant with neem oil or insecticidal soap usually gets rid of these pests. Follow the product instructions for optimal results. 

How to Propagate Tree Tomato

Tamarillos are best grown from stem cuttings. If you want to try your hand at growing from seeds, save the seeds from the fruit, wait for them to dry, and then sow the seeds in spring, covering them with 1/4 inch of soil. However, the resulting plants likely won't be identical to the parent plant.

If you want to propagate a tree tomato plant by cuttings, wait until the plant is mature and has a healthy stem and shoots. In early summer, take 10-inch cuttings from one-year-old wood, cutting just below a node. Remove the leaves from the bottom half of the cuttings and dip them in rooting hormone before placing them in small pots containing a well-draining potting mix. Place the pots in a protected area and water just enough to keep the potting mix somewhat moist. It may help to provide bottom heat. Roots should start to form in four to six weeks.

How to Harvest Tree Tomatoes

Expect your tree tomato to start producing fruit in its second growing season. Similar to tomatoes, the fruits are green as they are developing, and the skin turns colors as it ripens. The fruit skin can be purple, red, orange, or yellow. A tamarillo is ripe when the fruit gives a little when gently squeezed. Because the fruits don't last long after they are harvested, they are best when eaten within a few days.

Types of Tree Tomato

The most popular tree tomato variety in the U.S. is 'Oratia Red', which reaches maturity in only eight months. Other cultivars that grow well in home gardens include 'Rothhamer', 'Inca Gold', and 'Ecuadorian Orange'.

Tree Tomato Companion Plants

Borage

Borage is an excellent companion plant for tree tomato plantings. It helps reduce the dreaded hornworm by attracting beneficial insects. It also attracts pollinators, including bees and butterflies, to the garden. Both the leaves and flowers of the plant are edible and used as garnishes or herbs.

Basil

Basil, a familiar culinary herb, adds fragrant foliage to the garden. When planted near tree tomato plants, it repels thrips and hornworms. With many varieties of basil, growing from 18 inches to 4 feet tall, there's a basil suitable for every garden.

Marigolds

French marigolds and their taller cousins, African marigolds, add colorful blooms and attractive foliage to the garden. They have an impressive reputation for repelling a variety of pests, including whiteflies, nematodes, slugs, and snails.