Tomato ‘Giant Tree’, Solanum lycopersicum, is a fascinating old-fashioned tomato famous for producing exceptionally vigorous, tall-growing plants and large crops of meaty red tomatoes. Sometimes promoted historically as a “tree tomato” because of its enormous growth, it isn’t actually a tree at all. It is a very vigorous indeterminate tomato that can continue growing upwards and outwards for as long as warm conditions allow.

Giant Tree Tomato should also not be confused with Tamarillo, Solanum betaceum, which really does grow as a small tree and is sometimes called Tree Tomato. Giant Tree is a true garden tomato, just an extraordinarily vigorous one.

The variety has an interesting history and belongs to a group of giant-growing tomatoes that became popular with gardeners during the 20th century. These tomatoes were promoted for their ability to develop enormous vines when given a long growing season, rich soil, strong support and plenty of water.

Tomatoes themselves have a much older story. Their wild ancestors originated in western South America, particularly around present-day Peru, Ecuador and neighbouring areas. Tomatoes were domesticated in the Americas and were being cultivated in Mexico before being introduced into Europe during the 16th century.

From Europe they eventually spread around the world, with generations of gardeners selecting plants for different colours, shapes, flavours and growing habits. Some breeders concentrated on compact plants, while varieties such as Giant Tree went very much in the opposite direction!

Giant Tree produces large red tomatoes with substantial, juicy flesh and a rich traditional tomato flavour. Fruit size varies considerably according to growing conditions, but individual tomatoes can become impressively large when plants are well grown.

The tomatoes are excellent for slicing and are particularly good in sandwiches, burgers and salads. Their substantial flesh also makes them useful for sauces, soups, relishes, chutneys and cooked tomato dishes.

Tomatoes are wonderfully nutritious. They provide vitamin C, potassium, folate and vitamin K, together with dietary fibre and numerous naturally occurring plant compounds.

Red tomatoes are particularly well known for lycopene, the carotenoid antioxidant responsible for much of their deep red colouring. They also provide beta-carotene and other carotenoids. Cooking tomatoes, particularly with a little oil, can make some of their lycopene easier for the body to absorb.

The most remarkable feature of Giant Tree is the plant itself. This is an indeterminate tomato, meaning the growing tip doesn’t naturally stop after producing a set number of flower clusters. Instead, the plant continues producing stems, leaves, flowers and tomatoes throughout the growing season.

Under excellent conditions, the vines can reach several metres and become extremely large. Claims about spectacularly tall “tomato trees” usually involve plants given a very long growing season, ideal temperatures and substantial structures to climb. In an ordinary home garden, you should still expect a considerably larger plant than many standard tomato varieties.

Because of its size, Giant Tree needs serious support. A small tomato stake may quickly become inadequate. A sturdy trellis, strong cage, fence or other substantial structure is a much better choice.

The plant can also become quite broad if side shoots are allowed to grow freely. Gardeners with limited space can prune some of these shoots, while those wanting to discover just how enormous their Giant Tree can become may choose to provide a large framework and allow more stems to develop.

Small yellow flowers are produced in clusters and eventually develop into green tomatoes that gradually ripen to rich red.

Tomatoes are self-fertile, so a single plant can produce fruit. Bees are still valuable visitors, particularly buzz-pollinating bees, whose vibrations help release pollen within the flowers.

Giant Tree loves full sun and a long, warm growing season. Because it has the potential to produce such an enormous amount of growth, it appreciates deep, fertile soil containing plenty of compost or well-rotted organic matter.

Regular watering is particularly important. A huge plant covered with developing tomatoes requires considerable moisture, but try to keep watering consistent rather than allowing the soil to become extremely dry and then suddenly soaking it.

A generous layer of mulch helps retain soil moisture, suppress weeds and protect the roots during hot weather.

Feeding throughout the growing season can also be beneficial, particularly once flowering and fruit production are underway. Avoid excessive nitrogen, however, as this can encourage a magnificent jungle of leaves without a corresponding increase in tomatoes.

In frost-free conditions, indeterminate tomatoes can sometimes continue growing far longer than gardeners expect. In areas experiencing cold winters, however, Giant Tree is normally grown as a warm-season annual and will eventually be killed by frost.

How to Grow From Seed:

Sow Tomato Giant Tree seeds from late winter through spring under protection, or during spring and early summer once outdoor temperatures are reliably warm.

Sow seeds approximately 5 mm deep into good-quality moist seed-raising mix. Cover lightly and keep the mix consistently moist but not waterlogged.

Warmth encourages good germination. A temperature of approximately 20–25°C is ideal, with seedlings generally appearing within around 5–14 days.

Once seedlings have developed their first true leaves and are large enough to handle, transplant them into individual pots.

Grow the young plants somewhere warm and bright until the danger of frost has passed. Before planting outside permanently, gradually acclimatise them to outdoor conditions.

Plant seedlings approximately 70–100 cm apart. If you intend to allow the plants to reach their full potential, give them even more space.

Provide a very strong support at planting time. A substantial trellis, heavy-duty tomato cage or sturdy fence is preferable because established Giant Tree plants can become both tall and heavy.

Tomato seedlings can be planted more deeply than they were growing in their pots. Burying part of the stem encourages additional roots to develop and can help create a stronger root system to support the enormous plant above.

Choose a position receiving at least six hours of direct sunlight each day, preferably more. Prepare the soil generously with compost or well-rotted organic matter.

Water deeply and regularly throughout the growing season and mulch well around the root zone. Once flowering begins, feed periodically with a fertiliser suitable for tomatoes and other fruiting vegetables.

As the plant grows, continue securing the stems to their support. Soft garden ties are useful because they support the vines without cutting into the stems as they thicken.

Harvest tomatoes when they have developed their full red colour and feel slightly softer when gently held.

If you have plenty of space and have ever wondered just how enormous a tomato plant can become, Giant Tree is certainly one to try. Give it sunshine, rich soil, plenty of food and water and, most importantly, something seriously sturdy to climb – because this is one tomato that doesn’t seem to understand the meaning of “small garden plant”.