Liquorice: cultivation, care & benefits

Liquorice is not only the main ingredient in many sweets, but a well-loved garden plant, with unique leaves, blue blossom and easy maintenance. Read on to find out more.

It is easy to think that liquorice (Glycyrrhiza glabra) is only used in the production of sweets. However, the roots of this plant are also widely used in traditional medicine. Unfortunately, cultivating liquorice roots can take time; it takes about four years before the plant has enough root mass to harvest.

That said, the liquorice plant is very easy to care for, and a wonderful ornamental, so waiting for it to grow is not a struggle! Here is everything you need to know about liquorice – from growing the plant at home, to the medicinal uses of its roots.

Flavour, origin and characteristics of liquorice

The liquorice plant, which is originally from Southeast Asia, is very flexible. It does not depend on specific climatic conditions, and, as such, can be grown worldwide. Interestingly, the plant’s roots have been used for centuries, and were once considered quite sweet. Our modern palate, however, finds this sweetness dominated by a bitter, tart and anise-like taste.

Liquorice is a deciduous, perennial, herbaceous plant that, fully grown, can reach 60 to 180cm tall. The roots and rhizome of the liquorice plant are light brown and woody. Most commonly, the roots, which grow up to 12 meters long, are harvested and used. Each plant can produce 30 to 40 kilograms of root mass.

The liquorice plant belongs to the legume family (Fabaceae), and has blue-violet flowers that blossom relatively late in the year, from August until October. Liquorice leaves are also notable in their pinnate formation. That is, each stem has multiples leaves growing along its length.

Two varieties of liquorice are particularly prevalent in China: Glycyrrhiza yunnanensis and Glycyrrhiza uralensis. It is the roots of these wild, mature, Chinese varieties that are most closely related to the original liquorice plant, in both appearance, growth and substance.

Growing liquorice: Location, soil and care

Successfully growing liquorice is generally easy, even in places where the plant is not native. For optimal growth, however, look for full sunlight and loose, nutrient-rich, deep soil. The soil depth is especially important because liquorice develops a large taproot that grows very long. And if your soil is clayey or dense, enrich it with sand and loose potting soil, like our nutrient-rich Plantura Organic All Purpose Compost.

Tip: When farmed, liquorice is planted in raised mounds or ridges, as with asparagus and potato. If you can ridge plant in your garden, give it a go! It will make harvesting the plant much easier.

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Liquorice seeds can be sown outdoors from the end of May. However, they are most successful when pre-planted at home. If you harvest the seeds yourself, store them in the refrigerator for two to four weeks. The seeds need to be stimulated by the cold in order to germinate.

How to Grow Your Own Liquorice:

You can sow liquorice seeds indoors early; at the end of February. Just remember to keep the seeds in the refrigerator for two to four weeks, before steeping them in water for 24 hours to increase their germination rate.

After this, place the seeds in a container and cover them with a thin layer of soil. At this stage, a loose soil low in nutrients, like our Plantura Organic Herb & Seedling Compost, is ideal. The seeds will be unable to utilize any extra nutrients provided to them by the compost. Place your container in a warm location – about 20°C – and keep the soil moist but not wet. After 15 to 30 days, the seeds will begin to germinate.

It is important to give liquorice plants plenty of space to grow when they are planted outside at the end of May. Their root systems and rhizomes are strong and extensive. In our experience, it is best to give each seedling 50x50cm.

In general, it is possible to grow liquorice plants in pots. However, the pots must be large enough to allow the expansive taproots to grow. This is especially important if you would like to harvest liquorice roots. However, if you plan to keep liquorice indoors as an ornamental instead, install rhizome barriers to slow the plant’s growth.

Liquorice Location Requirements:

• Full sunlight.
• Sheltered from the wind.
• Deep, loose, nutrient-rich soil.
• A well-draining substrate to prevent waterlogging.
• Raised ridge planting to facilitate harvest.
• Rhizome barriers to prevent over-expansion.

Liquorice plant care

Liquorice is easy to care for. If you plant it in nutrient-rich soil, it will only need fertilising once a year, in spring. We recommend using an organic, slow-acting fertiliser, like our Plantura All Purpose Plant Food, or compost. Importantly, avoid general herb fertilisers, as they tend not to contain enough phosphor.

Due to its strong, extensive and deep root system, the liquorice plant typically fairs well in dry environments. However, during hot spells with little rainfall, it needs to be watered every couple of days.

Tip: If you plant your liquorice in a raised ridge, lay drip tubes around the plant. These will water the plants efficiently and evenly.

Liquorice plants can endure temperatures as low as -17°C. Because of this, you should have no trouble growing the plant in the UK. Nonetheless, young liquorice plants do appreciate a thermal layer during cold winters. After winter, prune back your liquorice by 5 to 10cm to allow room for hearty new growth in spring.

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How to harvest liquorice

If you are looking to harvest liquorice, patience is key. It takes three to four years before liquorice plants have enough root mass to survive a harvest. However, once the plant is well-established, you can harvest its roots annually.

The best time to harvest liquorice roots is in autumn, after the plant blossoms. At this time, the roots are at their sweetest. If you can, harvest the secondary roots and leave the primary taproots untouched. This will allow your plants to continue growing for years to come.

Benefits and uses of liquorice root

Liquorice is used extensively in traditional medicine. The root was revered by ancient Egyptians because of its healing power, and is foundational in Traditional Chinese Medicine (TCM). Additionally, liquorice roots can be used as an expectorant (like cough syrup), as well as a digestive aid.

Nowadays, liquorice root is used to alleviate flu-like infections, colds with a cough and upset stomachs. The most common way to consume liquorice root is in tea. Pour hot water over some finely chopped liquorice roots, allow them to steep for a few minutes, and there you have it! Liquorice root tea.

The liquorice plant (Glycyrrhiza glabra) contains Glycyrrhizin, which is about fifty times sweeter than sugar. The roots of this plant are calorific, as they also contain fructose and glucose, however the number of calories in liquorice roots is insignificant in comparison to common sugar.

Although liquorice can be beneficial, it does have some unpleasant side effects. Pregnant women, for instance, should not eat liquorice because the root inhibits the breakdown of cortisol. This effectively reduces inflammation, but can be harmful to the development of an unborn child. People with high blood pressure, diabetes or kidney problems should talk to their doctor before eating liquorice, as it increases blood pressure and blood sugar levels.

Liquorice is an ingredient in many herbal and medicinal teas. However, there are plenty of other herbs that are suitable for teas. Find more information and sample recipes in our article about herbal tea blends to grow at home.