Common Name: American Liquorice

General Information

Glycyrrhiza lepidota is a herbaceous perennial plant with an unbranched stem; it can grow 30 - 90cm tall[].
The plant is harvested from the wild for local use as a medicine and a food.
Glycyrrhiza lepidota is widespread and while it is possibly declining in parts of its range, it is not thought that any global population decline is likely to meet (or be close to meeting) the threshold for Vulnerable. The plant is classified as 'Least Concern' in the IUCN Red List of Threatened Species(2013)[].
The plant is a pioneer species in sandy, moist habitats, and can become a noxious weed[].

Known Hazards

Very young growth can be poisonous to animals[].
Whilst licorice is basically a very safe and effective medicine, when used over a long period or in large quantities it can raise the blood pressure[]. A gross overdose of the root can cause oedema, high blood pressure and congestive heart failure[, ].

Botanical References

Range

N. America - Saskatchewan to British Columbia, south to California and Mexico.

Habitat

Usually grows in patches, most often in moist habitats such as lakeshores, riverbanks, depressions, along irrigation canals, discharge areas and waste areas, also in cultivated ground, roadsides, prairies; at elevations up to 2,100 metres[]

Properties

Conservation Status	Least Concern
Edibility Rating
Medicinal Rating
Other Uses Rating
Habit	Perennial
Height	1.00 m
Pollinators	Insects
Cultivation Status	Wild

Cultivation Details

Glycyrrhiza lepidota is a plant of the temperate to subtropical zones of N. America, where it is found at elevations up to 2,100 metres. It grows best in areas where annual daytime temperatures are within the range 10 - 17°c, but can tolerate 4 - 23°c[]. When dormant, the plant can survive temperatures down to about -5°c, but young growth is more tender and can be severely damaged at -1°c[]. It prefers a mean annual rainfall in the range 450 - 500mm, but tolerates 350 - 550mm[]. Considering the plants native range, I find the temperature and rainfall figures given above to be somewhat suspect. The plant is likely to tolerate somewhat higher daytime temperatures, to be considerably more cold tolerant, and to also succeed in areas with considerably more rainfall[].
Requires a deep well cultivated fertile moisture-retentive soil for good root production[]. Prefers a sandy soil with abundant moisture[]. Plants are frequently found in the wild in heavy clay and saline soils[]. Slightly alkaline conditions produce the best plants[]. Prefers a pH in the range 6 - 7.5, tolerating 5.5 - 8.5[].
A very deep-rooted plant, it can be difficult to eradicate once it is established[].
Unless seed is required, the plant is usually prevented from flowering so that it puts more energy into producing good quality roots[].
Plants are growing very well at Kew[].
This species has a symbiotic relationship with certain soil bacteria, these bacteria form nodules on the roots and fix atmospheric nitrogen. Some of this nitrogen is utilized by the growing plant but some can also be used by other plants growing nearby[].

Edible Uses

Root - raw or cooked[, , , ]. Long, sweet and fleshy[], when slow roasted they are said to taste like sweet potatoes[, ]. They can be used as a flavouring in other foods and can also be chewed raw as a masticatory[, , ], making an excellent tooth cleaner and also very good for teething children. The root contains 6% glycyrrhizin, a substance that is 50 times sweeter than sugar[].

The tender young shoots can be eaten raw in the spring[, ].

Medicinal

American liquorice was widely employed medicinally by a number of native North American Indian tribes who used it in the treatment of a range of diseases[]. All parts of the body are medicinal, but the roots are the most active part. This species has properties similar to other liquorices which are widely used medicinally, though this species is rather neglected in modern literature. Some caution needs to be exercised in the use of this plant - it is generally very safe but large doses or extended use can increase the blood pressure[].

An infusion of the root is used to speed the delivery of the placenta after childbirth, it is also used to treat coughs, diarrhoea, chest pains, fevers in children, stomach aches etc[, ]. In modern herbalism, the root is considered to be a useful treatment against gastric and duodenal ulcers, bronchial asthma and is used as an additive in cough syrups[]. The chewed root is retained in the mouth as a treatment for toothache and sore throats[, ]. It is said to strengthen the voice for singing[].
Used externally, the root is employed as a wash or poultice on swellings[].

The mashed leaves are used as a poultice on sores and to treat earache[, , ].

Other Uses

The leaves have been placed in the shoes to absorb moisture[].

The roots can be chewed raw as a masticatory[, , ], making an excellent tooth cleaner and also very good for teething children.

Propagation

Pre-soak the seed for 24 hours in warm water and then sow spring or autumn in a greenhouse[]. Prick out the seedlings into individual pots when they are large enough to handle, and grow them on for their first winter in a greenhouse. Plant out in late spring or early summer when in active growth. Plants are rather slow to grow from seed[].
Division of the root in spring or autumn. Each division must have at least one growth bud. Autumn divisions can either be replanted immediately or stored in clamps until the spring and then be planted out[]. It is best to pt up the smaller divisions and grow them on in a cold frame until they are established before planting them out in the spring or summer.