Liquorice (Licorice) care

Light

Most houseplants will scorch where liquorice thrives. Give it the windowsill you'd otherwise leave empty because everything else burned there. Demands full sun — minimum 6–8 hours of direct sunlight daily. Insufficient light results in weak, unproductive plants with thin roots. South-facing borders or polytunnels are ideal in the UK climate. A plant moved abruptly from low light to direct sun bleaches in 48 hours — always acclimatise over a week.

Watering

Aim for weekly during active growth; reduce in autumn for liquorice, but treat that as a starting point rather than a rule. A south-facing summer windowsill will dry the pot twice as fast as a north-facing winter room. Lift the pot; if it feels noticeably lighter than it did wet, water it. Needs consistent moisture during spring and summer to support vigorous root development. Water deeply but infrequently to encourage deep taproot growth. Reduce watering significantly in autumn; roots can rot if kept wet through winter dormancy.

Soil and pot

Liquorice grows best in deep, fertile, sandy loam. Requires deep, well-drained, fertile sandy loam to allow unrestricted taproot development (roots can reach 1 m+). Soil pH 6.0–8.0; tolerates slight alkalinity. Heavy clay soils produce stunted, forked, lower-quality roots. Dig deeply and incorporate organic matter before planting. A pot with a working drainage hole is non-negotiable for this species — even free-draining mix will turn soggy in a closed planter. If you love the look of a decorative pot without a hole, use it as a cachepot around an inner nursery pot you can lift out to water.

Humidity and temperature

Liquorice sits happiest at around 40–65% humidity and -15–35°C (5–95°F). Adapts to a range of humidity levels suited to temperate climates. Tolerates the moderate humidity of UK summers without issue. Avoid persistently damp, airless conditions that promote foliar disease. If you keep the room above year-round and avoid placing the plant near a cold draught, a hot radiator, or an air-conditioning vent, you have already handled the two biggest indoor stressors.

Fertilising

Feed liquorice sparingly. Apply a balanced granular fertiliser (10-10-10) in early spring as growth resumes. Liquorice is a nitrogen-fixing legume, so supplemental nitrogen is minimal; focus on phosphorus and potassium to support root development. Avoid high-nitrogen feeds which promote leafy growth at the expense of root yield. Skip fertiliser entirely on a stressed, recently-repotted, or actively wilting plant — fertiliser salts make damage worse, not better. Wait for a round of healthy new growth before resuming a feeding rhythm.

Common problems

Below are the issues we see most often on liquorice in the Growli community. Each is annotated with the most common cause so you know where to start.

• Invasive spreading via stolons — Liquorice spreads aggressively via underground stolons and can become weedy. Install root barriers 40–50 cm deep around the planting area, or grow in large, deep containers to contain spread. Remove unwanted shoots promptly before they establish.
• Root rot in poorly drained soil — Heavy or waterlogged soils cause root and crown rot, leading to plant collapse. Ensure excellent drainage — raise beds or mound planting positions by 15–20 cm. In persistently wet regions, grow in large containers with a fast-draining mix.
• Slow establishment and patience required for harvest — Roots reach usable size only after 3–4 years. Premature harvest yields thin, bitter roots lacking glycyrrhizin. Mark plants clearly and resist harvesting early; use the waiting period to allow the colony to establish and expand.

Propagation

Propagate by division of rootstock in early spring or autumn, ensuring each division has at least one growth bud. Root cuttings (5–10 cm sections) can be taken in late winter and planted horizontally 5 cm deep. Seed germination is slow and variable; soak seed for 24 hours before sowing at 20°C in spring. Propagation is the cheapest, most satisfying way to expand a collection — and it doubles as insurance against losing a mature plant to an accident. Take a backup cutting once the parent is established and healthy.

Toxicity to pets

Liquorice is mildly toxic to pets. Glycyrrhiza glabra is not listed as toxic by ASPCA for dogs or cats. However, glycyrrhizin, the key active compound in the root, can be harmful in large or repeated doses to both humans (causing pseudohyperaldosteronism — sodium retention, potassium loss, hypertension) and pets. Casual contact or small incidental ingestion is low-risk, but concentrated root preparations or large quantities should be kept away from pets, particularly those with cardiac or renal conditions. If you keep cats, dogs, or curious children in the house, weigh placement carefully — a high shelf or a hanging planter is enough for casual safety. For severe ingestion incidents, call your local vet and the ASPCA Animal Poison Control Center (in the US, 888-426-4435).

Pet-safety status is sourced from the ASPCA Toxic and Non-Toxic Plant List, which catalogues the most-asked-about plants for cats, dogs, and horses.

Liquorice deep-dive guides

Every aspect of liquorice care, each with its own calibrated guide:

• Common liquorice problems & fixes
• Liquorice watering schedule
• Liquorice light requirements
• Best soil mix for liquorice
• Liquorice fertilizing guide
• When to repot liquorice
• How to propagate liquorice
• How to prune liquorice
• What's eating my liquorice?
• Liquorice growth rate & size
• Liquorice cold hardiness
• Liquorice temperature & humidity
• Is liquorice toxic to cats & dogs?
• Is liquorice toxic to cats?
• Is liquorice toxic to dogs?

Related guides

Liquorice is also known as Liquorice, Licorice, Sweet Root, and Common Liquorice.

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• All 8452 plant care guides in the Growli library