Amaranthus dubius aka Spleen Amaranth

Amaranthus dubius, or spleen amaranth, belongs to the Amaranthaceae family. Its native range includes tropical South America and the West Indies. Range records also cover Central America, north to Mexico. It has become naturalised in Europe, Asia, and North America. In Florida, it grows on disturbed ground and waste land. People gather it from the wild for food. They also grow it as a leaf crop in tropical regions.

This upright annual has a branched stem and vigorous growth. Listed garden height is about 3.3 feet [1 metre]. A broader reported range reaches 1–4.9 feet [0.3–1.5 metres]. The plant completes its life cycle in one growing season. British records place its leaf season from April to October. Flowers appear from July to September, followed by ripe seeds from August to October. Each plant bears separate male and female flowers. Wind carries the pollen, and plants can also fertilise themselves.

Give this plant sun and moist soil with good drainage. It grows in sand, loam, or clay. Fertile ground and a warm, sheltered site suit it best. It tolerates mildly acid through alkaline soil. Its preferred pH range is 6–7.5. Daytime temperatures of 22–30°C support its best growth. It is frost tender, and temperatures at or below 4°C can kill it. In Britain, it can grow as a spring-sown annual. Sow outdoors in late spring, or start under glass. Set young plants out after the last expected frost.

Warm soil helps seeds sprout well and soon after sowing. A cooler night can help germination. Cuttings from growing plants also root with ease. The first leaf harvest may come 30–50 days after sowing. Cooked leaves serve as a green vegetable. The small seeds are also edible when cooked. They can be ground into powder or cooked whole. Whole seeds become jelly-like, though some may pass through the gut undigested.

The leaves and stems contain nitrate and oxalate. The stems hold more nitrate than the leaves. Cooking in plenty of water, then discarding that water, removes some soluble compounds. This is not a crop to treat as an unrestricted raw green. Beyond food, the whole plant yields yellow and green dyes. The supplied references report no known medicinal uses.