Garlic mustard: identification, cultivation & uses

For thousands of years, garlic mustard, also known as jack-by-the-hedge, has been used as a medicinal and culinary herb. However, because this aromatic herb is not an onion plant, it lacks the common taste and smell of onions.

Garlic mustard (Alliaria petiolata) is often found growing in the forest, in shady areas or along the edges of gardens and paths. It is very useful in the kitchen as the leaves taste like pepper and garlic. And it can be harvested as early as March. Learn how to grow garlic mustard in your garden and what to look out for when taking care of your garlic mustard plant.

Garlic mustard: origins, flower and characteristics 

Garlic mustard (Alliaria petiolata) is a biennial herbaceous plant of the cruciferous family (Brassicaceae). The medicinal and culinary herb is also known as garlic root, hedge garlic, or jack-by-the-hedge. This plant is native to Europe, Central Asia and North Africa but it is considered an invasive species in North and South America. Hedge garlic thrives in shady deciduous forests with nitrogen-rich soil. The garlic root grows 20 to 100cm tall and has a deep taproot. Garlic mustard has heart-shaped leaves with grooved edges that are often 10cm in diameter and smell like garlic when crushed, hence the herb’s name. The lower leaves are more rounded whereas the higher growing leaves are pointed. Many small, white, four-petalled flowers appear in clusters between April and July, providing nectar to many insects, including native butterflies, particularly the orange-tip and green-veined-white butterflies. After flowering, elongated seed capsules with numerous small, black seeds form in the summer.

Easily confused: Garlic mustard is sometimes confused with ground ivy (Glechoma hederacea) due to the similar shape of the leaves, but ground ivy’s leaves are much smaller. Importantly, garlic mustard leaves smell like garlic, mustard and pepper when crushed.

Planting garlic mustard: where and how

Garlic mustard thrives in shady to semi-shady spots, especially near trees, shrubs and hedges. It prefers soil that is well-drained, humus and nutrient rich, and has a neutral pH. Apply lime if your soil is acidic to raise the pH. If your soil is very loamy or sandy, we recommend improving it with a high-quality potting soil, such as our Plantura Organic All Purpose Compost, which provides all the nutrients the hedge garlic needs while also retaining water well.

Garlic mustard can be grown from seed as well as from young plants. The plants must be exposed to cold temperatures to germinate, which is why they cannot be grown on a windowsill. Sow the seeds outdoors from October to February.

Sowing garlic mustard:

• Choose a shady spot and prepare the bed or pot for sowing. Remove all weeds and mix in plenty of nutrient-rich potting compost into very sandy or loamy soil.
• Mark the spot so you can find it in the spring.
• Sow the seeds 15cm apart and 1cm deep, then cover with soil.
• The seeds do not need to be watered and will germinate the following spring.

Tip: You can also grow garlic mustard in a pot. To do this, fill the pot with a loose, nutrient-rich potting compost, such as our Plantura Organic All Purpose Compost. Then sow the seeds. Simply leave the pot outside over winter. Water regularly from March onward.

How to care for garlic mustard

In autumn and spring, remove all weeds that compete with garlic mustard from the planting area. From March on, keep the soil moist at all times and water frequently during prolonged periods of drought. Because garlic mustard requires a lot of nitrogen, it is beneficial to apply a fertiliser in the second subsequent years of growth. Our Plantura All Purpose Plant Food is high in nitrogen and slowly releases nutrients over at least three months. Work the fertiliser into the soil in spring.

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Propagating garlic mustard

Once established in the garden, garlic mustard reproduces on its own. Seeds form after the second year. These seeds disperse by themselves in the surrounding area and begin to grow over time. There are usually only a few plants at first, but after a few years, the area will be completely taken over by hedge garlic.

To harvest the seeds, you must first pick capsules to get to the seeds inside. Cut the seed capsules off with scissors when they turn from green to brown. Collect the seeds by opening the capsules over a bowl. After a few days of drying in the open air, store the seeds in a dark container in a cool place.

Is garlic mustard edible?

All parts of the garlic mustard plant are edible. It is easiest to use the leaves when cooking, which can be picked from March onwards. Younger leaves are more aromatic than older leaves. The roots can also be eaten and the seeds have the strongest flavour. Hedge garlic tastes like garlic, mustard and pepper.

Uses and side effects

For many years, leaves, seeds and roots of the garlic mustard have been used in naturopathy as a tea or ointment. Among other things, the plants contain mustard oil glycosides, saponins and essential oils that are expectorant and antibacterial. The leaves can be used for a variety of purposes in the kitchen. Jack-by-the-hedge enhances salads, dips, pestos and other dishes. Do not dry the leaves and roots as this leads to a loss of flavour. When spices were too expensive, the wild herb was a popular alternative for seasoning. In folk medicine, the garlic root was used as a tea or ointment for a variety of illnesses.

FYI: Eating garlic mustard does not cause smelly breath unlike garlic and onion.

If you prefer a more intense garlic flavour, you can plant wild garlic. It is a close relative of true garlic with strong tasting leaves that thrive in a semi-shady and moist location.