Alstroemeria ligtu aka Saint Martin's Lily

Alstroemeria ligtu is a flowering perennial from South America. Plants For A Future lists it in several Chilean regions. Useful Tropical Plants gives a wider range, reaching Peru and western Argentina. It grows in dry scrub on rocky, sandy ground. Some habitats have dry spells lasting three to five months. Others have no clear dry season. Gardeners grow it for its flowers and edible roots.

The plant grows from a tuberous rootstock below ground. It sends up a group of upright, soft stems. Useful Tropical Plants gives a height of about 2 feet [0.6 metres]. The roots spread and form a large clump over time. This growth makes it a lasting plant rather than an annual. Its lily-like flowers have a sweet scent like mignonette. Insects pollinate the flowers. Growers value the blooms because they last well after cutting.

Choose a warm spot in sun or partial shade. The soil should be fertile and hold some moisture. It must also drain well. Moisture retention and good drainage are both part of its stated needs. One report says established plants can cope with drought. That does not mean young plants need dry soil. Useful Tropical Plants reports tolerance of brief frosts near 23°F [-5°C]. This figure describes short cold spells, not a full winter hardiness range.

Seeds and division offer two ways to raise more plants. Sow fresh seed in separate pots in a cold frame. Move seedlings with care while they are still small. Stored seed needs a warm soak and staged temperature treatment. Plants For A Future describes warm treatment followed by cooler conditions. Divide plants in April or October, taking care with the roots. Each piece needs a growth bud. The plant dislikes root disturbance, so careful handling matters during division.

People gather the roots from wild plants for local food use. They also sell some roots in local markets. Cooked roots provide starch, and Plants For A Future rates them as edible. It lists no known medicinal use. Edible roots do not make the sap harmless to touch. Fresh sap can cause a rash in sensitive people. Those who react to tulip sap may also react to this plant. The sources do not establish whether it harms pets.