Tree spinach: origin, sowing & harvest

Tree spinach is a leafy vegetable that stands out in the garden with its height and unique colouring. Of course, it’s easy upkeep is also a bonus.

As indicated by its Latin name, tree spinach (Chenopodium giganteum) is a large plant. With a height of up to 3m, it can grow 60 times taller than its namesake, spinach (Spinacia oleracea). From sowing and care to harvesting and use, find out here how to grow tree spinach yourself.

Tree spinach: origin and characteristics

Tree spinach is also known as giant goosefoot and is a member of the goosefoot genus (Chenopodium). Thus, tree spinach is a close relative of quinoa (Chenopodium quinoa) and of Good King Henry (Chenopodium bonus-henricus). More distant relatives are other plants of the amaranth family (Amaranthaceae) such as amaranths (Amaranthus), spinach and cultivated forms of beets (Beta vulgaris), such as beetroot (Beta vulgaris subsp. vulgaris var. conditiva) and chard (Beta vulgaris subsp. vulgaris). Tree spinach originates in the Himalayan regions of India, Nepal and Tibet. In these regions, the plant is also cultivated and used as a leafy vegetable.

Note: tree spinach is also the common name for Cnidoscolus aconitifolius, which is additionally known as chaya or spinach tree. While Cnidoscolus aconitifolius is used much the same way as Chenopodium giganteum, the two are not related.

Tree spinach is an annual herb that can grow to between 2 to 3m high and about 2m wide with sufficient water and nutrients. The stems grow upright and are strongly branched in their upper portion. Tree spinach stems grow up to 5cm in diameter and develop a slight magenta colouring in autumn.

When tree spinach leaves first emerge, they typically have a bright magenta colouring. As they mature, they become light green on top and dark green on the underside, retaining some of the magenta colouring close to their base. Tree spinach leaves are about 20cm long, ovate, irregularly toothed and appear somewhat rough.

Between July and September, tree spinach plants produce inconspicuous purple-red flowers in the form of a panicle. After pollination by wind, the lentil-shaped, dark red Chenopodium giganteum seeds form.

What varieties of tree spinach are there? Tree spinach is hardly commercially cultivated as a vegetable, so there are few varieties. In fact, most commercially available seeds come from wild forms of the plant. Additionally, because of tree spinach’s striking colouring, it is also sometimes cultivated as an ornamental plant; ˈMagentaspreenˈ tree spinach, which grows somewhat more compact than other varieties, is popular for this purpose.

Sowing and planting

Tree spinach is an undemanding plant and will grow in almost any location. A loose, nutrient-rich subsoil in a sunny to semi-shady location is ideal for this annual. Loosen and prepare about 2m² of soil per plant before sowing or planting.

Growing tree spinach in a pot is also possible. Just make sure you have a sufficiently large pot with a diameter of about 40cm. We suggest using a high-quality, nutrient-rich and loose soil, such as our Plantura Organic Tomato & Vegetable Compost. The production of our peat-free vegetable soil emits about 60% less CO2 from raw material extraction than conventional peat-based soils.

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Sow tree spinach seeds directly in your garden bed from April to June. If you wish to pre-cultivate your tree spinach, sow your seeds in a pot starting in March. Place the seeds on the soil and press them down lightly; do not cover them with compost. The seeds germinate at a temperature of 18 to 22 °C within 2 to 3 weeks. Once the seedlings are well rooted, plant your pre-cultivated tree spinach outdoors, spacing the plants 1.5 to 2m apart. The same spacing should also be observed when sowing the seeds directly in beds; the plants may later need to be separated if they outgrow their space.

Tip: tree spinach plants need a lot of space to grow. For this reason, they are typically not grown in the vegetable bed but rather on their own as individual plants.

As tree spinach is an annual, it must be resown every year. You can count on 2 to 3 specimens to feed a family of four.

Good companion plants for tree spinach: when planting next to other plants, ensure that your tree spinach plants have plenty of space to grow. Plants that require little space, such as radishes (Raphanus sativus subsp. sativus) and carrots (Daucus carota subsp. sativus), are suitable companion plants for tree spinach.

Tree spinach care

Tree spinach plants are undemanding when it comes to care and only need support in wind-exposed locations. Thriving in Mediterranean environments, these plants can cope with drought. However, they will need to be watered during dry periods when their leaves start to droop. To help keep the moisture in the soil, add some mulch around the base of your plants.

At the time of planting, apply an organic slow-release fertiliser such as our Plantura All Purpose Plant Food. The high content of organic materials in our fertiliser ensures a healthy soil life that supports robust root growth; the more nutrients and water available to the tree spinach, the bigger it will grow.

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Propagation

After flowering, it takes about 4 weeks for the first seeds to form. To propagate a tree spinach yourself, it is important to let the seeds mature fully; this sometimes takes until November. Store the harvested seeds in a cool, dark and dry place. The seeds remain germinable for 4 to 5 years.

Tip: as tree spinach plants reproduce readily with their numerous seeds, it is possible that even without deliberate sowing in spring, new plants will emerge. If you wish to prevent this, remove the inflorescences before they mature.

Is tree spinach hardy?

As an annual, tree spinach cannot be overwintered; the plant starts to die when the seeds ripen. However, it can still tolerate temperatures of around – 10 °C from autumn to the beginning of winter.

Harvesting and preparing tree spinach

The leaves of tree spinach can be boiled, steamed, sautéed or eaten raw in a salad just like spinach. Before harvesting, a tree spinach plant needs to reach a certain size. The first harvest is usually 6 to 7 weeks after sowing. Typically, just the young, tender leaves and shoot tips of tree spinach are harvested. The older leaves can also be used, although these have a tarter taste. Never remove all leaves from the plant. Also, bear in mind, tree spinach contains saponins and oxalic acid, so regular raw consumption is not advised.

Tip: the seeds of Chenopodium giganteum are also edible and can be cooked and eaten like quinoa or ground into a flour.

Can you freeze tree spinach? Tree spinach leaves can be frozen to last longer. We recommend blanching the leaves like normal spinach before freezing them.

Is tree spinach edible or poisonous?

Cooked tree spinach is completely safe to eat. However, consumption of raw tree spinach leaves should be minimised, as the saponins and oxalic acid can irritate the stomach and kidneys.

How healthy is tree spinach?

Eating cooked tree spinach is healthy and makes a great substitute for normal spinach. The advantage of tree spinach is the almost year-round harvest, whereas normal spinach shoots quickly in summer.

Do you like large vegetable plants with ornamental value? Then you might be interested in planting artichokes (Cynara scolymus). Learn all you need to know about growing this Mediterranean vegetable here in our expert article.