Alliaria petiolata – Garlic Mustard

Also known as Hedge Garlic and Jack-by-the-hedge. A medium to tall biennial or short-lived perennial with small white, yellow-centred flowers. Flowers occur from April to June and are followed by long green seedpods that shed their seed from July onwards. The fresh green, heart-shaped leaves that are well toothed and smell of garlic when crushed are probably the easiest way to identify this plant.

Habitat Information

Garlic mustard is most characteristic of hedgerows, woodlands and riverbanks where the soil is moist and fertile. Avoids very acid soils. It requires a combination of moderate shade and occasional disturbance if it is not to be outcompeted by species that are more robust. A plant native to Britain, its population seems to have remained stable over the past forty years. Garlic mustard is famously the larval food plant of the Orange-tip butterfly particularly on damper more open sites such as riverbanks. Look out for the orange eggs laid just behind the flower. Less well known it is also an important food plant for the caterpillars of green-veined whites.

Growing Information

Grows readily from seed sown at any time of the year, it does however require a long period of chilling to break dormancy. If sowing in situ on sites that might be colonized by weeds, it is therefore best to sow in autumn. On sites that are moist and partially shaded the plants should look after themselves but if you find other species taking over try some moderate disturbance of the soil in late summer or autumn.

Garlic mustard is found in our EH1 and EW1 mixtures but could be added to EM8 and EP1. If grown specifically to encourage orange-tips try growing a small patch in full sun. This will be more attractive to the butterflies but might require you to weed the bed.