Liquorice

Liquorice: how do you recognise it?

Habit

Upright, bushy perennial about 1–1.2 m tall and 1 m wide; the foliage dies back in winter.

Leaves

Pinnate, with 9–17 oval leaflets; fresh green.

Flowers

Small pea-type flowers in pale blue to violet spikes from July to August.

Fruit

Small brown pods with a few seeds; seldom formed in cool summers.

Roots

Deep roots and underground runners; the roots are yellow inside and taste sweet.

Flowering: July–August · Harvest and fruit: October–November · Plants: March–May · Pruning: March

Why grow it?

• A distinctive herb with sweet-tasting roots that you can harvest and dry yourself.
• Graceful pinnate foliage and pale pea flowers in summer.
• A perennial: plant once and harvest for years.
• Tolerates drought once it is deeply rooted.
• Improves the soil because legumes fix nitrogen.

Liquorice: where does it grow best?

• Full sun; it grows best in a warm, sheltered spot.
• Deep, loose, well-drained loam; acid to chalky.
• Normally moist; it tolerates drought but not wet winters.
• Allow 60–100 cm per plant and give it room: the roots grow deep and wide.

Light

Sun

Soil type

Sand or loam

Acidity

Not fussy

Moisture

Normal

Size

1.2 m tall, 1 m wide

Hardiness

Hardy (to -20 °C)

Goes well with

• Sage: An aromatic plant that enjoys the same sunny, dry spot.
• Thyme: A low ground cover for the foot of tall liquorice.
• Lavender: Likes the same warm, well-drained position and attracts bees.
• Hyssop: A sturdy herb with blue flowers that tolerates drought.

Liquorice: when and how to plant it?

Plant in March–May.

1. Plant in March–May, once the soil no longer freezes and has warmed a little.
2. Loosen the soil to at least 40–60 cm deep, because the roots go deep.
3. Set the plant at the same depth as in its pot, or lay a piece of rhizome horizontally 5–10 cm deep.
4. Leave 60–100 cm between plants.
5. Water in straight away and spread a thin layer of mulch around the base.

Care

Water

In the first year, water regularly in dry weather. After that it draws water from deep down and usually looks after itself.

Feeding

Little needed; as a legume it makes its own nitrogen. A little compost in spring if you like.

Weeding

In the first year, keep the soil around young plants weed-free.

Containing

In spring, slice off runners that appear far from the clump, otherwise it spreads.

Harvesting

Lift the roots in October–November from plants three to four years old; leave a piece of rhizome in the ground to regrow.

Tip: Give it a spot of its own with deep, loose soil and wait until the plant is three to four years old before harvesting. Never take everything: leave a piece of rhizome to regrow.

Liquorice: when to prune it?

Pruning months: March.

When: No pruning is needed; cut off the dead foliage in March.

How:

• Cut the withered stems down to a few centimetres above the ground in late winter, in March.
• Also remove damaged or weak foliage.
• Remove runners that come up in the wrong place.

Caution: Liquorice spreads by underground runners and, with its deep roots, is hard to get rid of. Plant it where it may spread, or restrict it with a root barrier at least 40–60 cm deep.

Pruning: when and how · Pruning calendar and basic rules

Propagation

Division

In spring (March–April), cut off pieces of rhizome with at least one bud and plant them straight away 5–10 cm deep. This is the easiest method.

Seed

The seed has a hard coat: nick it lightly or soak it overnight and sow it indoors in spring at 18–20 °C. It takes a while to germinate.

Liquorice: how does it get through the winter?

Hardy to −20 °C.

• Hardy to about −20 °C: usually no problem in Belgium if the soil is well drained.
• The foliage dies back. Leave it until March or cut it off.
• Wet winters are a bigger risk than frost: make sure the soil drains well. A thin layer of mulch protects the crown.

Diseases and pests

• Root rot: The plant declines and the foliage yellows on heavy, wet soil. Plant in loose, well-drained soil.
• Slugs: Young shoots are nibbled in spring. Collect them in the evening or put down barriers.
• Aphids: On young shoots in spring. Spray them off with water; ladybirds help.
• No flowers: In a spot that is too cool or shady it flowers little. Choose a warm, sunny position.

Through the year

• March: Cut off the dead foliage. Plant or divide.
• April: Divide and plant. Watch for slugs.
• May: Plant. Mulch.
• June: Water in dry weather. Weed.
• July: Flowering begins. Check the runners.
• August: Full flower.
• September: Foliage starts to turn.
• October: Lift the roots of older plants.
• November: Dry the harvest. Leave a piece of rhizome in the ground.
• December: Rest.

Edible and useful

Roots (October–November)

Dig up the roots in October and November, as the foliage dies back, and only from plants that are three to four years old. Dig on one side of the plant, take the thick side roots and the long horizontal runners and leave a piece of rhizome in the ground to regrow. Fresh or dried, they taste sweet, of liquorice. Chew on a stick, or use a piece for tea or to flavour a dessert.

Storing

Scrub the roots under the tap and cut them into sticks of 10 to 15 cm; split thick pieces lengthways. Leave them to dry for a few weeks somewhere airy and warm, or in the oven at 40 to 50 °C with the door ajar (a few hours to a day, depending on thickness), until they are hard and snap cleanly. Dried, they keep for at least a year in a closed jar.

Caution: Liquorice contains glycyrrhizin. Taking a lot of it, or for a long time, can raise your blood pressure, make you retain fluid and lower the potassium in your blood, which can upset your heart rhythm. So use it in moderation: a stick or a cup of tea now and then, not every day for weeks, and count liquorice sweets and shop-bought liquorice tea too. Not with high blood pressure, heart or kidney problems or during pregnancy, nor if you take water tablets, blood pressure medicines, heart medicines (such as digoxin) or corticosteroids, unless your doctor agrees.

Eating and using is at your own risk: see the terms of use.

Recipes

• Liquorice sticks for chewing (Dried · ± 20 sticks · 20 min + 2 to 3 weeks drying)
• Liquorice and mint tea (Tea · 1 cup · 15 min)

Did you know?

• The scientific name Glycyrrhiza comes from Greek and means ‘sweet root’.
• Liquorice is a legume, so it is related to peas and beans.
• The substance that makes the root sweet is many times sweeter than sugar.