Alliaria petiolata - Garlic Mustard

Family: Brassicaceae (Mustard) ^[E-flora]

"Alliaria petiolata is a BIENNIAL growing to 1 m (3ft 3in) by 0.4 m (1ft 4in). It is not frost tender. It is in flower from Apr to June, and the seeds ripen from Jun to August. The flowers are hermaphrodite (have both male and female organs) and are pollinated by Bees, flies, lepidoptera, self.The plant is self-fertile.
It is noted for attracting wildlife.
Suitable for: light (sandy), medium (loamy) and heavy (clay) soils. Suitable pH: acid, neutral and basic (alkaline) soils. It can grow in full shade (deep woodland) or semi-shade (light woodland). It prefers moist or wet soil." ^[PFAF]

Introduction: "Garlic mustard is a highly invasive introduced species in the mustard family (Brassicaceae) that originates from Eurasia. In North America, it is found in many US states, particularly in the eastern US, though it is absent in the southern US states from Florida to California (USDA 2011). In Canada, it is found in British Columbia, New Brunswick, Nova Scotia, Ontario and Quebec. In Ontario, it is often a dominant understorey herb in disturbed sites and can form a thick ground cover. In BC, it is reported from the Okanagan, the Lower Mainland and the Victoria area. It is a biennial tap-rooted species with an erect form and white mustard-type flowers. It is easily recognized by its dark green kidney-shaped leaves and the noticeable garlic odour of crushed leaves. It is known to inhibit ectomycorrhizal fungi where it grows, which may influence seedling establishment of native species (Wolfe et al. 2008). There is evidence that some populations of this species in North America originated from the British Isles, though it is possible that there have been multiple introductions from other locations (Meekins et al. 2001)." ^[E-flora]

General: "Biennial herb from a taproot; stem erect and unbranched below inflorescence, sparsely hairy below, glabrous or with whitish bloom above, 20-120 cm tall; garlic smell, especially from root but also from crushed leaves." ^{[IFBC-E-flora]}

Notes: "Alliaria petiolata is considered an emerging invasive species in the Vancouver region by the Greater Vancouver Invasive Plant Council (2009). An emerging invasive is defined by them as: currently found in isolated, sparse populations but are rapidly expanding their range within the region." ^[E-flora]

Habitat / Range
"Mesic to dry disturbed sites and waste places in the lowland and lower montane zones; rare in SW and SC BC; introduced from Eurasia."^{[IFBC-E-flora]}

"The native range of this species is Europe to Central Asia and N. Myanmar, NW. Africa. It is an annual or biennial and grows primarily in the temperate biome." ^(PWO,2026) "Europe, south-western Asia, North Africa; introduced into North America, New Zealand" [MPFT]

Origin Status: Exotic. ^[E-flora]

Hazards

"a toxic FA, is sometimes reported in Cruciferae, for example, in Alliaria petiolata (Guil et al. 1997), and is also found in smaller amounts in some Caryopllyllaceae species, such as in Silene vulgaris (Alarcón et al. 2006). This FA, together with eicosenoic (20:1n-9) and nervonic (24:1n-9) acids, has been cited as responsible for congestive heart failure; so their presence in the diet has been associated with cardiotoxicity in humans (Imamura et al. 2013). In any case, the low fat content of the leaves makes it unlikely that the occasional consumption of A. petiolata (31 % EA of total FAs) would cause heart problems. However, it seems reasonable to avoid regular consumption of leaves or seeds of this species." ^{[Tardio MWEP]}

Erucic Acid: "Due to the unproven responsibility for the poisoning effect in TOS (Toxic Oil Syndrome), and the in vivo data on inducement of cardiotoxicity, erucic acid has been for decades classified as a toxic substance, the use of which should be rather avoided. It should be strongly emphasized however, that the cardiac adverse effects have not been confirmed in humans, and the experiments in animal models, performed mostly about four decades ago, had many limitations, including a small number of animals, or extremely high doses applied during long time exposure to EA (Table 1). Moreover, this effect was reversible in most cases. In our own opinion, the presented toxicological data clearly indicate that, when used in reasonable amounts, EA is not as toxic as it was previously believed." ^{(Galanty et al.,2023)}

"In 1981, a progressive multisystem disease, later called toxic oil syndrome, abruptly broke out in epidemic proportions in central and northwestern Spain (1). This previously unknown syndrome affected thousands of people, and several hundred deaths were attributed to toxic oil syndrome....Toxic oil syndrome resulted from the consumption of rapeseed oil that had been denatured with 2 percent aniline for industrial use, subsequently refined, and then illicitly sold as pure olive oil (3). To date, the causal toxic agent remains unknown, as many substances which could potentially be the causative compound have been found in the implicated oils (4, 5)." ^{(de la Paz et al.,2001)}

Food Usage

"Many species consumed during famine or food scarcity in the 19th century and during World War I in Germany and Austria [1], and common in Poland, e.g. Aegopodium podagraria and Alliaria petiolata, also do not appear in Polish culinary ethnographic literature either. The use of some of these species might have become obsolete before ethnographic studies began" ^{[Luczaj,2007]}

"Sisymbrium (Alliaria) alliaria (petiolata) Scop. Cruciferae. GARLICWORT. SAUCE-ALONE. This plant, of Europe and adjoining Asia, is the sauce-alone of Gerarde, who says "divers eat the stamped leaves hereof with salt fish, for a sauce, as they do those of ransons." It is the garlicwort of Turner and is eaten with meat, having a strong odor of garlic. According to Neill, when gathered as it approaches the flowering state, if boiled separately and then eaten with boiled mutton, it forms a desirable potherb. In Wales, it is often fried with bacon or herrings and is sometimes eaten as a salad. The Germans call it sasskraut and use it much as a salad in the spring. In England, it is used with lettuce." [Sturtevant EPW]

• Leaves: "Young leaves - raw or cooked as a potherb or as a flavouring in cooked foods[4, 5, 9, 12, 62, 115, 244]. A mild garlic and mustard flavour, the leaves are also believed to strengthen the digestive system[244]. They can be finely chopped and added to salads[7, 183]. The leaves are available very early in the year and provide a very acceptable flavouring for salads in the winter[K]." ^[PFAF] Leaves/shoots - "Use in salads or in cooked dishes (particularly later in the season when fiery hot raw)." ^{[Crawford FFFG]} "Young greens in salads, as potherbs, as pesto, or as a sauce" "Collect young basal leaves (those at the base of the plant), not the leaves on the flower stalk, which are too bitter." ^{[Lincoff TJF]} "The leaves of Sisymbrium alliaria Scop. (Hedge garlic) have a taste resembling that of garlic, and are used for seasoning foods." ^{[Middleditch KP]}
• "Flowers and young seed pods - raw[62]. A mild, garlic-like flavour[K]." ^[PFAF] "Flowers eaten raw" ^[EMNMPV.7]
• Seeds: "Use whole, or grind and use like mustard seeds." ^{[Crawford FFFG]} "The seeds of Sisymbrium canescens Nutt. (Tansy mustard) have been used as a condiment." ^{[Middleditch KP]}

Other Usage

• Dye: "A yellow dye is obtained from the whole plant[7]." ^[PFAF]

Herbal Usage

"Garlic mustard has been little used in herbal medicine[268]." ^[PFAF] "As its vernacular names indicate, Alliaria petiolata functioned as an alternative to garlic.Though that was chiefly in cooking, its leaves also substituted for garlic’s medicinally by being applied externally to sore throats in Kent (?)117 and chewed for sore gums and mouth ulcers in Norfolk.118 Rubbing the leaves on the feet was a cure for cramp in Somerset.119 More surprising, though, has been its use for wounds (again in Kent?).120" ^[MPFT]

• Leaves and Stems: "The leaves and stems are antiasthmatic, antiscorbutic, antiseptic, deobstruent, diaphoretic, vermifuge and vulnerary[4, 7]. The leaves have been taken internally to promote sweating and to treat bronchitis, asthma and eczema[4]. Externally, they have been used as an antiseptic poultice on ulcers etc[4], and are effective in relieving the itching caused by bites and stings[244]. The leaves and stems are harvested before the plant comes into flower and they can be dried for later use[238]." ^[PFAF] "The leaves and seeds of Sisymbrium qfficinale (L.) Scop. (Bank cress, Crambling rocket, Hedge mustard) have antiscorbutic properties, and have been employed medicinally as diuretics, expectorants, and stimulants. The leaves of this species have a strong odor similar to that of garlic." ^{[Middleditch KP]}
• Root: "The roots are chopped up small and then heated in oil to make an ointment to rub on the chest in order to bring relief from bronchitis[245]." ^[PFAF]
• Juice: "The juice of the plant has an inhibitory effect on Bacillus pyocyaneum and on gram-negative bacteria of the typhoid-paratyphoid-enteritis group[240]." ^[PFAF]
• Seeds "The seeds have been used as a snuff to excite sneezing[4]." ^[PFAF]
  

Indications: cramp, sore gums, sore mouth, sore throat, ulcers. [MPFT]

Acivities

"865. (1) Alliaria petiolata; (2) GARLIC-MUSTARD; ...; (5) antiseptic, detersive, diuretic, expectorant, stimulant, sudorific, vermifuge; (6) scurvy; (8) Dutch, French, German, Italian, Span- ish" [CRC Eth]

ALLYL-ISOTHIOCYANATE - Putative Anti-asthmatic Compounds - Plant [MPUC Trivedi]

Lore

"Alliaria. Alliaria officinalis Andrz. [Sisymbrium Alliaria, Scop. Erysimum Alliaria, L. Alliaria Alliaria (L.) Brit.] Hedge Garlic.—A perennial European herb, a native also of Northern Asia, and naturalized from Canada to Virginia, having an alliaceous odor when rubbed, and a bitterish, somewhat acrid taste. When eaten it communicates its odor to the breath. Wertheim obtained from the root a volatile oil, apparently identical with that of mustard. (Ann. Ch. Ph., liii, 52.) The herb and seeds are esteemed diuretic, diaphoretic, and expectorant, and are used as external applications in gangrenous affections, and to promote suppuration." ^{[Remington USD20]}

Phytochemicals

"Alliaria petiolata (garlic-mustard) has 19,000 units [of pro-vitamin A (beta carotene)] in its basal leaves" ^{[Haines AP]} "A. petiolata has the highest total carotenoid content (13.3 mg/100 g)" ^{[Tardio MWEP]}

"Despite sharing a common biosynthetic origin, the pathways of glucosinolates and cyanogenic glycosides are mutually exclusive [ 111 ] and coexist in only a few species in the order Brassicales (e.g., papaya ( Carica papaya ) and garlic mustard ( Alliaria petiolata )) and the Drypetes genus [ 119 , 124 , 125 ]." ^{[Jetter FSAP]}

Aerial Part
"Mustard oil
Content, %: 0.03–0.09 [1, 2]"
Seed
"Mustard oil
Content, %: 0.51–0.96 [1] Oil, % on dry wt: 22–30 [3–5]" ^[LLCEOPS]

Leaves: 2.1% Fat (Dry wt.) ^{[Tardio MWEP]}

15.8% oil content (seed)
unsaturated acid content (33.8%)
Erucic acid 49.3%
Linoleic 18.7%
Oleic 8.5%
Linolenic 6.6%
Eicosenoic 4.1%
Arachidic 0.2%
(Maršalkienė et al.,2009)

"The isolation protocols for .... flavonol glycosides from seeds of Agrimonia eupatoria (66) and Alliaria petiolata (36) demonstrate the successful application of solid- phase extraction method in natural product isolation." [Sarker NPI]

"Moreover, glucosinolates are also known for their inducibility. In a study on A. petiolata, invasive individuals contained reduced constitutive levels and increased induced levels of glucosinolates compared to native individuals (Cipol- lini et al. 2005). This may be a cost- saving strategy resulting from reduced selective pressure by herbi- vores (Koricheva et al. 2004)." (Doorduin&Vrieling,2011)

Cultivation
"Prefers a damp rich alluvial soil[7, 53]. Succeeds in damp shady places where few other herbs will grow[238]. A good woodland edge plant, it also grows well in the bottom of hedgerows[24] and will self-sow freely in suitable conditions[238]. On a calm day the plant emits a strong smell of garlic. This is especially pronounced if the leaves are bruised[245]. This species is an important food source for the orange-tip butterfly[238]." ^[PFAF]

Deer Resistant: "Rawinski (2008) reported that deer eat many herbaceous species on the forest floor but avoid others.... They seem to disproportionately avoid exotic invasives such as ... garlic mustard (Alliaria petiolata). The end result is forest floors dominated by a few unpalatable native species and invasive exotics." ^{[Beck PELD]}

Alleleopathy

"The Eurasian invasive plant Alliaria petiolata has been shown to slow the rate of arbuscular mycorrhizal infection of native tree seedlings in North America. This leads to reduced tree seedling growth rates, thereby facilitating its invasion of relatively undisturbed forest habitats (Stinson et al., 2006). The allelochemicals produced by A. petiolata degrade mycorrhizal fungi and persist in the soil, preventing mycorrhizal recolonisation even when mycorrhizal fungi are added to it (Stinson, Klironomos & Acland, 2005). This change favours early successional species over late successional woody species and may alter the successional dynamics of the invaded woodland (Stinson, Klironomos & Acland, 2005). Naphthoquinones are known to have anti-fungal properties (Curreli et al., 2001) and may work in a way analogous to the isothiocyanates believed to be responsible for A. petiolata’s inhibitory effects." ^[Smith,2013]

"Stinson et al. (2006) presented novel evidence that antifungal phytochemistry of the invasive plant, Alliaria petiolata, a European invader of North American forests, suppresses native plant growth by disrupting mutualistic associations between native canopy tree seedlings and belowground AM." ^{[Shah MNDCW]}

"Prati and Bosdorf (2004) reported that Alliaria peteolata, a devastating invader of North American temperate forests also had stronger chemical effects on Geum laciniatum, a new North American neighbor, than on G. urbanum, its natural European neighbor." ^{[Cheema Alleleopathy]}

"Alliaria petiolata , another non-mycorrhizal exotic invader, not only reduces AMF in this way, it also produces allelochemicals which inhibit AMF spore germination, further disrupting natives’ mutualistic relationships (Roberts and Anderson 2001 ; Stinson et al . 2006 )." ^{[Dighton IIS]}

"Garlic mustard [Alliaria petiolata (Bieb) Cavara & Grande (Brassicaceae)] is an herbaceous biennial that has invaded, and now dominates, much of the hardwood forest understory in the eastern and midwestern United States and southeastern Canada (Cavers et al., 1979; Nuzzo, 1991, 1993, 1998). It is displacing native flora, and it is unlikely that its elimination from heavily infested areas is possible (Anderson et al., 1996). Populations of native understory plants have been found to decline in areas with a heavy infestation of garlic mustard, which can be as high as 20,000 seedlings/m2 (Trimbur, 1973; Yost et al., 1991). Groundcover by native ephemerals declined as cover by garlic mustard increased (Nuzzo, 1998). Recent studies have shown that garlic mustard may also pose a threat to organisms other than higher plants, as Porter (1994) reported that adults of the endangered West Virginia white butterfly [Pieris virginiana (W. H. Edwards)], which normally feed on several Dentaria spp. (Brassicaceae), preferentially laid their eggs on garlic mustard plants. This occurs even though the plant appears to be moderately toxic to the developing larvae (Haribal and Renwick, 1998)." ^[vaughn1999]

"The host plants of the native American butterfly Pieris napi oleracea include most wild mustards. However, garlic mustard, Alliaria petiolata, a highly invasive weed that was introduced from Europe, appears to be protected from this insect. Although adults will oviposit on the plant, most larvae of P. n. oleracea do not survive on garlic mustard. By using feeding bioassays with different larval stages of the insect to monitor the isolation and identification of two bioactive constituents that could explain the natural resistance of this plant, Renwick et al. (2001) found that a cyanopropenyl glycoside, alliarinoside, strongly inhibits feeding by first instars through an apparent post-ingestive feedback mechanism, while a flavone glycoside, isovitexin-6″- d-β-glucopyranoside, acts as a direct feeding deterrent that is perceived by taste receptors on the mouthparts of late instars. Interestingly, the first instars are insensitive to isovitexin-6"-D-B-glucopyranoside, and the late instars are little affected by alliarinoside." ^{[Lattanzio RAPR]}

"Garlic mustard (Alliaria petiolata) is a herba- ceous biennial member of the Brassicaceae which has invaded, and in some areas domi- nates, a large part of the hardwood forest understory in the eastern U.S. and Canada.109 Populations of native plants such as cut-leaved toothwort (Dentaria laciniata) have declined in areas with extensive stands of garlic mustard, as well as several insect species which feed on these native plants.110,111 Decaying and/or crushed garlic mustard leaves emit high lev- els of AITC, while roots release primarily BITC (S. F. Vaughn, unpublished data). BITC could also be detected by solid phase microextraction from soil from areas heavily infested with garlic mustard. As previously noted, these isothiocyanates are potent inhibitors of seed germination and plant growth, and may be crucial in the dominance of garlic mustard in these forest ecosystems. Choesin and Boerner,112 studying the possible allelopathic nature of rapeseed plants, concluded that the release of AITC by these plants was insuffi- cient to inhibit neighboring plants. However, the major glucosinolates found in rapeseed are progoitrin, gluconapin, and glucobrassicanapin, with only trace amounts of sinigrin detected.102,113 Additionally, some of the most inhibitory hydrolysis products, such as AITC and BITC, are released only at very low levels by decaying rapeseed tissues, and may account for these results.22,23" [Cutler BANPA]

"There is also strong evidence that this contri- butes to A. petiolata’s invasiveness in North America, since Alliaria has a stronger inhibitory effect on North American plants and AMF than plants and AMF from its native European range (Callaway et al. 2008; Prati and Bossdorf 2004)." [Dighton IIS] "North American populations of the invasive plant Alliaria petiolata (Bieb.) Cavara and Grande also inhibited a naive North American species more than an experienced European congener, but European populations of A. petiolata did not affect the species differently, only partially supporting the novel weapons hypothesis [57]." [Pinton TR]

Propagation
"Seed - sow outdoors in situ either in spring or autumn." ^[PFAF]

Synonyms

• Alliaria alliaria (L.) Huth ^(PWO,2026) (L.) Britt. ^[E-flora]
• Alliaria officinalis ^[E-flora] Alliaria officinalis Andrz. ex M.Bieb. ^(PWO,2026)
• Erysimum alliaria L. ^{[E-flora](PWO,2026)}
• Sisymbrium alliaria (L.) Scop.^{(PWO,2026) [E-flora]}

References

• (de la Paz et al.,2001) de la Paz, Manuel Posada, Rossanne M. Philen, and Ignacio Abaitua Borda. "Toxic oil syndrome: the perspective after 20 years." Epidemiologic reviews 23.2 (2001): 231-247.
• Doorduin&Vrieling,2011 - Doorduin, Leonie J., and Klaas Vrieling. "A review of the phytochemical support for the shifting defence hypothesis." Phytochemistry Reviews 10.1 (2011): 99-106.
• [E-flora] http://linnet.geog.ubc.ca/Atlas/Atlas.aspx?sciname=Alliaria%20petiolata [Accessed: 6/13/2015]
• (Galanty et al.,2023) Galanty, A.; Grudzińska, M.; Paździora, W.; Paśko, P. Erucic Acid—Both Sides of the Story: A Concise Review on Its Beneficial and Toxic Properties. Molecules 2023, 28, 1924. https://doi.org/10.3390/molecules28041924
• Luczaj,2007 - Łuczaj, Łukasz, and Wojciech M. Szymański. "Wild vascular plants gathered for consumption in the Polish countryside: a review." Journal of Ethnobiology and Ethnomedicine 3.1 (2007): 17.
• (Maršalkienė et al.,2009) Maršalkienė, N., et al. "Oil content and fatty acid composition of seeds of some Lithuanian wild crucifer species." Agron. Res 7 (2009): 654-661.
• [PFAF] http://www.pfaf.org/user/Plant.aspx?LatinName=Alliaria+petiolata, Accessed June 13, 2015
• (PWO,2026) Alliaria petiolata (M.Bieb.) Cavara & Grande, https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:1176324-2#synonyms, Accessed Feb 16, 2026
• Smith,2013 - Smith, Owen Peter. "Allelopathic Potential of the Invasive Alien Himalayan Balsam (Impatiens glandulifera Royle)." (2013).
• vaughn1999 - Vaughn, Steven F., and Mark A. Berhow. "Allelochemicals isolated from tissues of the invasive weed garlic mustard (Alliaria petiolata)." Journal of chemical ecology 25.11 (1999): 2495-2504.

Image References

• 1, Alliaria petiolata, Robert Flogaus-Faust, CC BY 4.0 , via Wikimedia Commons
• 2, Alliaria petiolata, Krzysztof Ziarnek, Kenraiz, CC BY-SA 4.0 , via Wikimedia Commons
• 3, Alliaria petiolata, Robert Flogaus-Faust, CC BY 4.0 , via Wikimedia Commons

Journals of Interest

• Barto EK, Cipollini D. 2009. Half-lives and field soil concentrations of Alliaria petiolata secondary metabolites. Chemosphere 76: 71–75. Blair AC, Nissen SJ, Brunk GR, Hufbauer RA. 2006. A lack
• Kumarasamy Y, Byres M, Cox PJ, Delazar A, Jaspars M, Nahar L, Shoeb M, Sarker SD: Isolation, structure elucidation, and biological activity of flavone 6-C-Glycosides from alliaria petiolata. Chem Nat Compounds 2004, 40(2):122–128.
• Lankau R (2010) Soil microbial communities alter allelopathic competition between Alliaria petiolata and a native species. Biol Invasions 12:2059–2068
• Lankau RA (2011) Resistance and recovery of soil microbial communities in the face of Alliaria petiolata invasions. New Phytol 189:536–548
• Prati D, Bossdorf O (2004) Allelopathic inhibition of germination by Alliaria petiolata (Brassicaceae). Am J Bot 91:285–288
• Rodgers VL, Wolfe BE, Werden LK, Finzi AC (2008) The invasive species Alliaria petiolata (garlic mustard) increases soil nutrient availability in northern hardwood-conifer forests. Oecologia 157:459–471
• Roberts KJ, Anderson RC (2001) Effect of garlic mustard [Alliaria petiolata (Beib. Cavara & Grande)] extracts on plants and arbuscular mycorrhizal (AM) fungi. Am Midl Nat 146:146–152
• Cipollini D, Mbagwu J, Barto K, Hillstrom C, Enright S (2005) Expression of constitutive and inducible chemical defenses in native and invasive populations of Alliaria petiolata. J Chem Ecol 31:1255–1267
• Lewis KC, Bazzaz FA, Liao Q, Orians CM (2006) Geographic patterns of herbivory and resource allocation to defense, growth, and reproduction in an invasive biennial, Alliaria petiolata. Oecologia 148:384–395
• Blažević, Ivica, and Josip Mastelić. "Free and bound volatiles of garlic mustard (Alliaria petiolata)." Croatica chemica acta 81.4 (2008): 607-613.
• Frisch, Tina, et al. "Glucosinolate-related glucosides in Alliaria petiolata: sources of variation in the plant and different metabolism in an adapted specialist herbivore, Pieris rapae." Journal of Chemical Ecology 40.10 (2014): 1063-1079.

Alliaria Sp.

The genus Alliaria contains 3 accepted, 17 synonyms and 1 unassessed species. ^{[ThePlantList]} There appears to be little information online about this genus. ^{[PersonalNote]}

Local Species;

• Alliaria petiolata - Garlic Mustard ^[E-flora]

References

• [ThePlantList] http://www.theplantlist.org/1.1/browseBrassicaceae/Alliaria/, Accessed June 13, 2015

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