Zanthoxylum americanum

Zanthoxylum americanum

The common prickly ash or, also, northern prickly-ash, toothache tree, yellow wood, suterberry (Zanthoxylum americanum Mill.) Is a shrub species belonging to the Rutaceae family.

Systematics –
From a systematic point of view it belongs to:
Eukaryota Domain,
Kingdom Plantae,
Magnoliophyta Division,
Magnoliopsida class,
Subclass Rosidae,
Sapindales Order,
Rutaceae family,
Subfamily Zanthoxyloideae,
Genus Zanthoxylum,
Species Z. americanum.
The terms are synonymous:
– Thylax fraxineum (Willd.) Raf.;
– Xanthophyllon clavatum St.-Lag.;
– Zanthoxylum americanum f. americanum;
– Zanthoxylum americanum f. armatius F.C.Gates;
– Zanthoxylum americanum f. impuniens Fassett;
– Zanthoxylum caribaeum Gaertn.;
– Zanthoxylum cauliflorum Steud.;
– Zanthoxylum clava-herculis Lam.;
– Zanthoxylum clava-herculis var. americanum Du Roi;
– Zanthoxylum fraxineum Willd.;
– Zanthoxylum fraxinifolium Marshall;
– Zanthoxylum mite Willd.;
– Zanthoxylum ramiflorum Michx.;
– Zanthoxylum tricarpum Hook..

Etymology –
The term Zanthoxylum comes from the Greek ξανθὸν ξύλον, which means yellow wood.
The specific americanum epithet refers to its American origin.

Geographic Distribution and Habitat –
Zanthoxylum americanum is a plant native to the central and eastern portions of the United States and Canada and is the northernmost species of Rutaceae in North America.
The natural distribution of this plant is rare in the south and more common in the northern United States. In the United States it is found in Alabama, Arkansas, Connecticut, Delaware, District of Columbia, Florida, Georgia, Iowa, Illinois, Indiana, Kansas, Kentucky, Louisiana, Massachusetts, Maryland, Maine, Michigan, Minnesota, Missouri, North Carolina, North Dakota, Nebraska, New Hampshire, New Jersey, New York, Ohio, Oklahoma, Pennsylvania, Rhode Island, South Carolina, South Dakota, Tennessee, Virginia, Vermont, Wisconsin, and West Virginia; the species is also found in Ontario and Quebec in Canada. This species is listed as Endangered in Florida, Maryland, and New Hampshire and as a Special Concern in Tennessee.
Its habitat is that of the undergrowth of dense-growing maple oak woods often on rocky areas, well-drained shallow soils, tuffaceous or other igneous substrates, at altitudes of 1,350–1,750 meters.

Description –
Zanthoxylum americanum is a shrub that forms a bush up to about 3 meters high (some specimens rarely go over 7.5 meters) and often densely branched above the middle.
It has smooth bark, gray to dark brown in color with lighter spots and scattered, small, light-colored, fairly circular lenticels; the bark becomes slightly grooved on old trunks; the bark is armed with small, flattened spines, slightly curved downwards. Soft, not strong, light brown wood.
The twigs are stiff, smooth, dark brown to gray in color; they have a pair of thorns on each node, each thorn about 3.5 cm long, flat, broad-based, curved.
The leaves are alternate, compound pinnate, 10-30 cm long, aromatic, with about 2,5 cm long stems; the leaflets in number of 5-11; the lateral leaflets without a peduncle and the terminal leaflet with a short stem; the leaflets become progressively longer from the basal pair, ranging from about 2 to 7.5 cm in length and 1 – 3.8 cm in width, egg-shaped or half the length wide, the pointed and blunt tip, the rounded base, the entire or finely rounded and toothed margin; the upper surface is of an opaque intense green color, dotted with glands; the lower surface lighter, hairy on the veins.
It is a dioecious plant with single short-stemmed flowers and male (staminate) and female (pistillate) flowers usually on separate plants. The sepals are absent. Petals 4 or 5, wider in the center, minute, yellowish green in color, usually with a fringe of short, frizzy, reddish-brown hairs. The male flowers with 4 or 5 stamens, alternating with the petals; the female flowers are about 3.5 cm long, longer than the male flowers, with 2-5 ovaries per flower.
The anthesis is between April and May, before the leaves form, in small axillary clusters of 2-10, on the twigs of the previous year.
The fruits that form between June and August, in dense clusters, are green to reddish brown in color, strongly aromatic, about 3.5 – 5 cm long, globe-shaped, firm, fleshy, pitted on the surface, which split on one side.
The seeds are 1 or 2, oval, about 0.3 cm long, finely pitted, glossy black; the seed coat is oily and aromatic.

Cultivation –
Zanthoxylum americanum is a shrub or small thorny and deciduous tree that produces suckers, often forming dense formations of the undergrowth, and is a plant that has long been harvested in nature to be used mainly as a medicine; however it is also the source of an essential oil and the seeds are used as a condiment. The plant is occasionally cultivated for ornamental purposes as its thorny nature and its bearing produce a dense natural barrier.
For its cultivation it prefers humid but well-drained and deep soils, in full sun or semi-shade but it also grows well in poor soils.
It is a relatively fast growing plant reproducing by means of root suckers.
Propagation is by seed. The seed should be sown as soon as it ripens in the autumn period. Stored seeds can take up to 3 months of cold stratification, although scarification can also aid germination. In this sense it is advisable to soak the seeds stored for 12 hours in warm water, then sow in an unheated seedbed as soon as possible during the year. Germination should take place in late spring, although it could take another 12 months. The young seedlings are then placed in individual pots and developed in a protected environment for the first winter. The transplant is then carried out at the beginning of the summer.
It can also be propagated through cuts of half-ripe wood in the period of mid-summer in a shaded area or by root cuttings, 3 cm long, planted horizontally in pots in a greenhouse.
It can also be propagated using suckers, removed at the end of winter and planted directly in the open field.

Customs and Traditions –
Zanthoxylum americanum is a plant known to the indigenous peoples of North America and was originally described by the Scottish botanist Philip Miller in 1768.
All parts of the plant are scented. The foliage, especially when crushed, gives off a delicious resinous scent similar to orange.
The broken twigs give off a strong smell reminiscent of crushed lemon peel.
This plant is used for both food and medicinal purposes.
In food use, cooked seeds are used as a condiment instead of pepper.
In its medicine it is used as a warming and stimulating herb that is beneficial for circulation. It was highly regarded by the Native Indians of North America who used it especially to relieve rheumatism and toothache.
An oil extracted from the bark and follicles has been used in herbal medicine. The extract can act as a stimulant, and historical medicinal use has included use for chronic rheumatism, typhus and skin diseases and blood impurities, as well as for digestive disorders.
The berries are considered even more active than the bark, being carminative and antispasmodic, and are used as aperient and for dyspepsia and indigestion.
The bark was chewed for toothache and a tea was used for a sore throat and as a diuretic.
Presumably the stems and fruits were chewed by the Indians to relieve toothache as the acrid juice has a numbing effect.
Wood has no commercial value, but bark oil extracts have been used in traditional and alternative medicine and have been studied for antifungal and cytotoxic properties.
All parts of the plant, but especially the bark and roots, contain the aromatic bitter oil xanthoxylin which has numerous applications in medicine, particularly in the treatment of arthritic and rheumatic conditions, digestive problems and leg ulcers.
There have been some modern studies on the chemical constituents of oil and their antifungal and cytotoxic effects.
The bark and roots are antirheumatic, diaphoretic, irritant, odontalgic, stimulant and a useful tonic in the treatment of debilitated states of the stomach and digestive organs.
They produce arterial excitation and are useful in the treatment of fevers, malaria, poor circulation, etc.
Bark infusions were once taken internally as a treatment for back pain, cramps, lung problems, to treat fever, and as a remedy for colds and coughs.
The bark was boiled in a decoction which was taken to induce miscarriages. Bark infusions have been taken to treat worms in adults.
The bark was used in different forms to relieve toothache: it was smoked, beaten or dried and pulverized, crammed in and around a aching tooth; pieces of the bark were chewed to help break a tooth that needed to be removed.
One report states that the bark is very effective, but that the sensation of acrid bark in the mouth is as unpleasant as a toothache.
The bark infusion, applied externally, was used as a wash to treat itchy skin and to treat swollen joints. Weak children were washed with bark decoction to make legs and feet strong.
A poultice made from the inner bark was used to treat rheumatism and acute pains. Placing the inner cortex in the throat treated the sore throat.
A tea made from the inner bark has been used as a cleanser to treat itchy skin and swollen joints.
The root bark was used to treat colic, rheumatism and gonorrhea.
The infusions, made from crushed roots, were used to treat fevers.
Fruits are considered more active than the bark. They are antirheumatic, antispasmodic, carminative, diaphoretic, diuretic, stimulant and a useful tonic in the treatment of debilitated states of the stomach and digestive organs.
The infusions of the berries were sprinkled on the chest and throat to treat bronchial diseases, to wash sores and to aromatize medicines.
By rubbing the fruit against the peel, especially on the lips or in the mouth, a paralyzing effect is obtained.
The bark and berries were used together to treat bleeding, to make cough syrup, as an expectorant, and to treat tuberculosis.
The plant was used to treat pain after childbirth.
An ointment from the plant mixed with bear fat was applied to the ulcers and sores.
The plant was an ingredient in compounds that were used for kidney problems, to strengthen convalescent patients, and to induce vomiting.
Other uses include agroforestry, where the plant is used as a natural barrier due to its thorny and very dense vegetation.
In addition, the fruits were used by young people as a perfume.
Wood, on the other hand, is soft and of little use.
From the ecological point of view it is reported that some butterflies use Zanthoxylum americanum as a food source for the larvae; among these the Papilio thoas, the Papilio cresphontes and the Papilio troilus.

Preparation Method –
In food use, cooked seeds are used as a condiment instead of pepper.
From the bark infusions are obtained, as mentioned, for various remedies; the bark was boiled in a decoction which was taken to induce miscarriages. Bark infusions have been taken to treat worms in adults.
In general, the bark was used in different forms.
From the bark a poultice was obtained for various remedies and a tea obtained from the inner bark was used for other remedies.
Infusions were obtained from the crushed roots but also the fruits were employed and used similarly to the bark.
An ointment from the plant was mixed with bear fat.
In 2012, a Pennsylvania distillery introduced a bitter called Bartram’s Bitters that uses Zanthoxylum americanum bark as one of several botanical ingredients. The blend was based on a recipe for “Bartram’s Homestead Bitters” which was found in a book that belonged to the family of botanist John Bartram.

Guido Bissanti

– Acta Plantarum – Flora of the Italian Regions.
– Wikipedia, the free encyclopedia.
– GBIF, the Global Biodiversity Information Facility.
– Useful Tropical Plants Database.
– Conti F., Abbate G., Alessandrini A., Blasi C. (ed.), 2005. An annotated checklist of the Italian vascular flora, Palombi Editore.
– Pignatti S., 1982. Flora of Italy, Edagricole, Bologna.
– Treben M., 2000. Health from the Lord’s Pharmacy, Advice and experiences with medicinal herbs, Ennsthaler Editore.
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Warning: Pharmaceutical applications and alimurgical uses are indicated for informational purposes only, they do not represent in any way a medical prescription; therefore no responsibility is taken for their use for curative, aesthetic or food purposes.

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