Three-cornered garlic belongs to the Amaryllidaceae family. Native to the Mediterranean, three-cornered garlic was introduced into gardens. Three-cornered garlic is now widely established across the country and is commonly found growing on roadsides, banks, hedges, and shaded areas. It is not very tolerant of extreme cold or frost and is more common in the South and South East of the country.
Three-cornered Garlic (Allium triquetrum)
Classified as a medium impact invasive species by the Irish National Biodiversity Centre. Third Schedule listed species under Regulations 49 & 50 in the European Communities (Birds and Natural Habitats) Regulations 2011.
- Identified by its bell-shaped white flowers that are seen from April to June.
- White flowers have a green stripe in the centre of each petal.
- The stems are three sided from which the name is derived.
- Leaves are long, narrow and green with 2-5 leaves on each bulb.
- Distinct garlic smell when crushed.
Each plant has male and female parts. Plants are pollinated by insects. Seeds fall off near the plant but can spread further away by ants or water and germinate readily.
Three cornered garlic can form dense colonies that can outcompete native plants for space and light. It is an aggressive invasive that can overtake large areas of land and outcompete native grasses particularly.
Chemical: Three cornered garlic can be treated with a glyphosate-based herbicide before flowering in Spring.
Mechanical: Three cornered garlic can be excavated and fully removed and disposed of in a licensed waste facility or moved to a deep cell on site. Removal should take place in Spring when above ground vegetation is present. Soil around the plant should be excavated too to ensure seeds are removed.
Biological: All parts of the plant can be eaten. Digging up plants and consuming plants is another possible method of control.
(National Biodiversity Data Centre, Ireland, Three-cornered Garlic (Allium triquetrum), image, accessed 11 January 2023)