Lactuca serriola aka Prickly Lettuce

Lactuca serriola, or prickly lettuce, belongs to the daisy family, Asteraceae. Other names include compass plant, horse thistle, and milk grass. It grows as an annual or biennial in temperate regions. Kew records Türkiye within its native range. The RHS also lists it as native to Britain and Ireland. Reported habitats include waste ground, walls, and some stable dunes.

Plants reach about 5 feet [1.5 metres] tall. Their spread is about 1 foot [0.3 metres]. The upper leaves line up north–south, giving rise to the name compass plant. Wounds release a milky sap that dries on contact with air. Young leaves can taste mild, but older growth becomes bitter. This change is more marked as flowering starts. Flowers appear from July to September. Seeds ripen during August and September. Each flower has male and female organs, and plants are self-fertile.

Give this plant a sunny site with soil that drains well. It cannot grow in shade, according to Plants for a Future. A light sandy loam suits it best. It also grows in sandy and loamy soils. It accepts mildly acid, neutral, and mildly alkaline conditions. Although drainage matters, it prefers moist soil. Plants for a Future lists USDA hardiness zones 6–9. Sow seeds where plants will grow in spring. Cover them with only a thin layer of soil. Germination is generally quick.

Young leaves can be eaten raw or cooked. Tender leaves suit salads, while cooked leaves need little cooking. Young shoots can also be cooked as an asparagus substitute. Large servings can upset digestion, and mature plants are mildly toxic. These limits matter when considering it as a food plant. The seeds yield oil, but this needs refining before eating. The plant is grown for seed oil in Egypt. Its oil also has uses in soap, paint, and varnish.

The sap contains lactucarium, a substance with recorded medicinal uses. These include pain relief, sedation, and help with sleep. Such records do not establish that home use is safe. Plants for a Future flags this species as potentially weedy. That concern matters when choosing a place in cultivated beds. Its documented uses centre on food, oil, and traditional medicine.