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Datasheet

Marrubium vulgare (horehound)

Summary

  • Last modified
  • 03 January 2018
  • Datasheet Type(s)
  • Invasive Species
  • Host Plant
  • Preferred Scientific Name
  • Marrubium vulgare
  • Preferred Common Name
  • horehound
  • Taxonomic Tree
  • Domain: Eukaryota
  •   Kingdom: Plantae
  •     Phylum: Spermatophyta
  •       Subphylum: Angiospermae
  •         Class: Dicotyledonae
  • Summary of Invasiveness
  • M. vulgare is a perennial flowering plant native to North Africa, Europe and parts of Asia. It has been introduced to Japan, southern Africa, the Americas, Australia and New Zealand, and has been recorded as in...

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Pictures

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PictureTitleCaptionCopyright
Marrubium vulgare (horehound or white horehound); plant, showing habit and foliage. American River Preserve, California, USA.
TitleHabit and foliage
CaptionMarrubium vulgare (horehound or white horehound); plant, showing habit and foliage. American River Preserve, California, USA.
Copyright©Barry Rice/sarracenia.com/Bugwood.org - CC BY-NC 3.0 US
Marrubium vulgare (horehound or white horehound); plant, showing habit and foliage. American River Preserve, California, USA.
Habit and foliageMarrubium vulgare (horehound or white horehound); plant, showing habit and foliage. American River Preserve, California, USA.©Barry Rice/sarracenia.com/Bugwood.org - CC BY-NC 3.0 US
Marrubium vulgare (horehound or white horehound); flowers, showing false whorls or verticillasters.
TitleFlowers
CaptionMarrubium vulgare (horehound or white horehound); flowers, showing false whorls or verticillasters.
Copyright©Trevor James-2014/Hamilton, New Zealand
Marrubium vulgare (horehound or white horehound); flowers, showing false whorls or verticillasters.
FlowersMarrubium vulgare (horehound or white horehound); flowers, showing false whorls or verticillasters.©Trevor James-2014/Hamilton, New Zealand
Marrubium vulgare (horehound or white horehound); established plant with with old, matured seed heads.
TitleEstablished plant
CaptionMarrubium vulgare (horehound or white horehound); established plant with with old, matured seed heads.
Copyright©Trevor James-2014/Hamilton, New Zealand
Marrubium vulgare (horehound or white horehound); established plant with with old, matured seed heads.
Established plantMarrubium vulgare (horehound or white horehound); established plant with with old, matured seed heads.©Trevor James-2014/Hamilton, New Zealand
Marrubium vulgare (horehound or white horehound); young  vegetative plant.
TitleYoung vegetative plant
CaptionMarrubium vulgare (horehound or white horehound); young vegetative plant.
Copyright©Trevor James-2014/Hamilton, New Zealand
Marrubium vulgare (horehound or white horehound); young  vegetative plant.
Young vegetative plantMarrubium vulgare (horehound or white horehound); young vegetative plant.©Trevor James-2014/Hamilton, New Zealand
Marrubium vulgare (horehound or white horehound); close-up of leaves on a young vegetative plant.
TitleLeaves
CaptionMarrubium vulgare (horehound or white horehound); close-up of leaves on a young vegetative plant.
Copyright©Trevor James-2014/Hamilton, New Zealand
Marrubium vulgare (horehound or white horehound); close-up of leaves on a young vegetative plant.
LeavesMarrubium vulgare (horehound or white horehound); close-up of leaves on a young vegetative plant.©Trevor James-2014/Hamilton, New Zealand
Marrubium vulgare (horehound or white horehound); foliage. American River Preserve, California, USA.
TitleFoliage
CaptionMarrubium vulgare (horehound or white horehound); foliage. American River Preserve, California, USA.
Copyright©Barry Rice/sarracenia.com/Bugwood.org - CC BY-NC 3.0 US
Marrubium vulgare (horehound or white horehound); foliage. American River Preserve, California, USA.
FoliageMarrubium vulgare (horehound or white horehound); foliage. American River Preserve, California, USA.©Barry Rice/sarracenia.com/Bugwood.org - CC BY-NC 3.0 US
Marrubium vulgare (horehound or white horehound); flower spike. Nevada, USA.
TitleFlower spike
CaptionMarrubium vulgare (horehound or white horehound); flower spike. Nevada, USA.
Copyright©Bonnie Million/National Park Service/Bugwood.org - CC BY-NC 3.0 US
Marrubium vulgare (horehound or white horehound); flower spike. Nevada, USA.
Flower spikeMarrubium vulgare (horehound or white horehound); flower spike. Nevada, USA.©Bonnie Million/National Park Service/Bugwood.org - CC BY-NC 3.0 US
Marrubium vulgare (horehound or white horehound); flowers. Nevada, USA.
TitleFlowers
CaptionMarrubium vulgare (horehound or white horehound); flowers. Nevada, USA.
Copyright©Bonnie Million/National Park Service/Bugwood.org - CC BY-NC 3.0 US
Marrubium vulgare (horehound or white horehound); flowers. Nevada, USA.
FlowersMarrubium vulgare (horehound or white horehound); flowers. Nevada, USA.©Bonnie Million/National Park Service/Bugwood.org - CC BY-NC 3.0 US
Marrubium vulgare (horehound or white horehound); dried flower spike, showing seed pods. Nevada, USA.
TitleDried flower spike
CaptionMarrubium vulgare (horehound or white horehound); dried flower spike, showing seed pods. Nevada, USA.
Copyright©Bonnie Million/National Park Service/Bugwood.org - CC BY-NC 3.0 US
Marrubium vulgare (horehound or white horehound); dried flower spike, showing seed pods. Nevada, USA.
Dried flower spikeMarrubium vulgare (horehound or white horehound); dried flower spike, showing seed pods. Nevada, USA.©Bonnie Million/National Park Service/Bugwood.org - CC BY-NC 3.0 US
Marrubium vulgare (horehound or white horehound); fruits; dorsal view of two nutlets, truncate apex at top. CPHST, Fort Collins, Colorado, USA.
TitleFruits
CaptionMarrubium vulgare (horehound or white horehound); fruits; dorsal view of two nutlets, truncate apex at top. CPHST, Fort Collins, Colorado, USA.
Copyright©D. Walters & C. Southwick/USDA/Bugwood.org - CC BY-NC 3.0 US
Marrubium vulgare (horehound or white horehound); fruits; dorsal view of two nutlets, truncate apex at top. CPHST, Fort Collins, Colorado, USA.
FruitsMarrubium vulgare (horehound or white horehound); fruits; dorsal view of two nutlets, truncate apex at top. CPHST, Fort Collins, Colorado, USA.©D. Walters & C. Southwick/USDA/Bugwood.org - CC BY-NC 3.0 US

Identity

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Preferred Scientific Name

  • Marrubium vulgare L.

Preferred Common Name

  • horehound

International Common Names

  • English: white horehound

Local Common Names

  • : common horehound; hoarhound; hound's bane; woolly horehound
  • : marrubio común
  • : ou xia zhi cao (transcribed)
  • : roubiya (Egypt); ze kom (Saudi Arabia)
  • : šandra obyknovennaja (transcribed)
  • France: marrube blanc
  • Germany: Andorn
  • Portugal: marroio
  • Sweden: kransborre

Summary of Invasiveness

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M. vulgare is a perennial flowering plant native to North Africa, Europe and parts of Asia. It has been introduced to Japan, southern Africa, the Americas, Australia and New Zealand, and has been recorded as invasive in many of these territories (PIER, 2013). It tends to invade land that has been disturbed, overgrazed or previously grazed by sheep. It can form large dense patches with greater than 75% cover, excluding native vegetation and altering grassland structure. Two biological control agents of M. vulgare, the horehound plume moth (Wheeleria spilodactylus) and horehound clearwing moth (Chamaesphecia mysiniformis), have been released in Australia.

Taxonomic Tree

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  • Domain: Eukaryota
  •     Kingdom: Plantae
  •         Phylum: Spermatophyta
  •             Subphylum: Angiospermae
  •                 Class: Dicotyledonae
  •                     Order: Lamiales
  •                         Family: Lamiaceae
  •                             Genus: Marrubium
  •                                 Species: Marrubium vulgare

Notes on Taxonomy and Nomenclature

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Mabberley (1997) noted 30 European species of Marrubium, with 12 from the Mediterranean area.

Description

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Modified from Weeds of Australia (2013):

Upright or spreading, perennial, much-branched herb with stems square in cross-section, up to about 60 cm tall, more or less covered in woolly interwoven hairs. The oppositely-arranged leaves are also densely covered in woolly hairs. The lower leaves have longer petioles than the upper ones, up to 10-25 mm long. The leaves are 1-70 mm long and 8-45 mm wide, egg-shaped or almost rounded in outline and crinkly in appearance. They have bluntly toothed margins and a rounded tip. The white tubular flowers, each 6-12 mm long, are borne in dense clusters in the axils of the upper leaves. The flowers are two-lipped, the upper lip being divided into two lobes and the lower into three lobes. The flowers are surrounded by a persistent green calyx tube of fused sepals with ten narrow teeth. The fruit contains four seeds or nutlets enclosed in the old flower calyx, which has ten backward-curved teeth or spines. The seeds are 1-2.5 mm long, egg- or pear-shaped, and with a slightly rough surface texture.

Plant Type

Top of page Perennial
Vegetatively propagated

Distribution

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M. vulgare is native to North Africa, Europe and parts of Asia, and has been introduced to Japan, southern Africa, the Americas, Australia and New Zealand.

In Australia M. vulgare is widely distributed throughout the south-east, occurring in areas with over 200 mm annual rainfall. It covers over 26 million ha, with the heaviest infestations in north-western Victoria and south-eastern South Australia, where semi-arid conditions lead to decreased vigour of competing plant species (Weiss et al., 2000). Weiss et al. (2000) suggested that M. vulgare has probably reached its maximum potential distribution – but not its potential density – in Australia, as a result of its invasive nature and early introduction to that country.

Distribution Table

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The distribution in this summary table is based on all the information available. When several references are cited, they may give conflicting information on the status. Further details may be available for individual references in the Distribution Table Details section which can be selected by going to Generate Report.

Continent/Country/RegionDistributionLast ReportedOriginFirst ReportedInvasiveReferenceNotes

Asia

AfghanistanPresentNativeUSDA-ARS, 2013
ArmeniaPresentNativeUSDA-ARS, 2013
AzerbaijanPresentNativeUSDA-ARS, 2013
ChinaPresentPresent based on regional distribution.
-XinjiangPresenteFloras, 2013Dry grassy loess slopes
IndiaPresenteFloras, 2013
IranPresentNativeUSDA-ARS, 2013
IsraelPresentNativeUSDA-ARS, 2013
JapanPresentIntroducedMito and Uesugi, 2004
JordanPresentNativeUSDA-ARS, 2013
KazakhstanPresentNativeUSDA-ARS, 2013
KyrgyzstanPresentNative
LebanonPresentNativeUSDA-ARS, 2013
NepalPresentGBIF, 2013
PakistanPresentNativeUSDA-ARS, 2013
Saudi ArabiaPresentNativeGBIF, 2013
SyriaPresentNativeUSDA-ARS, 2013
TaiwanPresentIntroducedGBIF, 2013
TajikistanPresentNativeeFloras, 2013
TurkeyPresentNativeUSDA-ARS, 2013
TurkmenistanPresentNativeUSDA-ARS, 2013
UzbekistanPresentNativeUSDA-ARS, 2013
YemenPresentNativeGBIF, 2013

Africa

AlgeriaPresentNativeUSDA-ARS, 2013
LesothoPresentIntroducedUSDA-ARS, 2013
LibyaPresentNativeUSDA-ARS, 2013
MoroccoPresentNativeUSDA-ARS, 2013
South AfricaPresentIntroducedUSDA-ARS, 2013Eastern Cape
Spain
-Canary IslandsPresentNativeUSDA-ARS, 2013
TunisiaPresentNativeUSDA-ARS, 2013

North America

CanadaPresentPresent based on regional distribution.
-British ColumbiaPresentIntroducedUSDA-NRCS, 2013
-Nova ScotiaPresentIntroducedUSDA-NRCS, 2013
-OntarioPresentIntroducedUSDA-NRCS, 2013
-QuebecPresentIntroducedUSDA-NRCS, 2013
-SaskatchewanPresentIntroducedUSDA-NRCS, 2013
MexicoPresentIntroducedMalezas de Mexico, 2013
USAPresentPresent based on regional distribution.
-AlabamaPresentIntroducedUSDA-NRCS, 2013
-AlaskaPresentIntroducedUSDA-NRCS, 2013
-ArizonaPresentIntroducedUSDA-NRCS, 2013
-ArkansasPresentIntroducedUSDA-NRCS, 2013
-CaliforniaPresentIntroducedUSDA-NRCS, 2013
-ColoradoPresentIntroducedUSDA-NRCS, 2013
-ConnecticutPresentIntroducedUSDA-NRCS, 2013
-DelawarePresentIntroducedUSDA-NRCS, 2013
-District of ColumbiaPresentIntroducedUSDA-NRCS, 2013
-GeorgiaPresentIntroducedUSDA-NRCS, 2013
-HawaiiPresentIntroducedUSDA-NRCS, 2013
-IdahoPresentIntroducedUSDA-NRCS, 2013
-IllinoisPresentIntroducedUSDA-NRCS, 2013
-IndianaPresentIntroducedUSDA-NRCS, 2013
-IowaPresentIntroducedUSDA-NRCS, 2013
-KansasPresentIntroducedUSDA-NRCS, 2013
-KentuckyPresentIntroducedUSDA-NRCS, 2013
-LouisianaPresentIntroducedUSDA-NRCS, 2013
-MainePresentIntroducedUSDA-NRCS, 2013
-MarylandPresentIntroducedUSDA-NRCS, 2013
-MassachusettsPresentIntroducedUSDA-NRCS, 2013
-MichiganPresentIntroducedUSDA-NRCS, 2013
-MinnesotaPresentIntroducedUSDA-NRCS, 2013
-MississippiPresentIntroducedUSDA-NRCS, 2013
-MissouriPresentIntroducedUSDA-NRCS, 2013
-MontanaPresentIntroducedUSDA-NRCS, 2013
-NebraskaPresentIntroducedUSDA-NRCS, 2013
-NevadaPresentIntroducedUSDA-NRCS, 2013
-New JerseyPresentIntroducedUSDA-NRCS, 2013
-New MexicoPresentIntroducedUSDA-NRCS, 2013
-New YorkPresentIntroducedUSDA-NRCS, 2013
-North CarolinaPresentIntroducedUSDA-NRCS, 2013
-OhioPresentIntroducedUSDA-NRCS, 2013
-OklahomaPresentIntroducedUSDA-NRCS, 2013
-OregonPresentIntroducedUSDA-NRCS, 2013
-PennsylvaniaPresentIntroducedUSDA-NRCS, 2013
-Rhode IslandPresentIntroducedUSDA-NRCS, 2013
-South CarolinaPresentIntroducedUSDA-NRCS, 2013
-South DakotaPresentIntroducedUSDA-NRCS, 2013
-TennesseePresentIntroducedUSDA-NRCS, 2013
-TexasPresentIntroducedUSDA-NRCS, 2013
-UtahPresentIntroducedUSDA-NRCS, 2013
-VermontPresentIntroducedUSDA-NRCS, 2013
-VirginiaPresentIntroducedUSDA-NRCS, 2013
-WashingtonPresentIntroducedUSDA-NRCS, 2013
-West VirginiaPresentIntroducedUSDA-NRCS, 2013
-WisconsinPresentIntroducedUSDA-NRCS, 2013
-WyomingPresentIntroducedUSDA-NRCS, 2013

South America

ArgentinaPresentIntroducedWeiss et al., 2000
ChilePresentIntroducedWeiss et al., 2000
ColombiaPresentIntroducedGBIF, 2013
PeruPresentIntroducedWeiss et al., 2000
UruguayPresentIntroducedWeiss et al., 2000
VenezuelaPresentIntroducedGBIF, 2013

Europe

AlbaniaPresentNativeUSDA-ARS, 2013
AndorraPresentNativeGBIF, 2013
AustriaPresentNativeUSDA-ARS, 2013
BelarusPresentNativeUSDA-ARS, 2013
BelgiumPresentNativeUSDA-ARS, 2013
Bosnia-HercegovinaPresentNativeGBIF, 2013
BulgariaPresentNativeUSDA-ARS, 2013
CroatiaPresentNativeGBIF, 2013
CyprusPresentNativeUSDA-ARS, 2013
Czechoslovakia (former)PresentNativeUSDA-ARS, 2013
DenmarkPresentNativeUSDA-ARS, 2013
EstoniaPresentNativeUSDA-ARS, 2013
FinlandPresentNativeGBIF, 2013
FrancePresentNativeUSDA-ARS, 2013
GermanyPresentNativeGBIF, 2013
GreecePresentNativeUSDA-ARS, 2013
HungaryPresentNativeUSDA-ARS, 2013
IrelandPresentNativeGBIF, 2013
ItalyPresentNativeUSDA-ARS, 2013
LatviaPresentNativeUSDA-ARS, 2013
LithuaniaPresentNativeUSDA-ARS, 2013
LuxembourgPresentNativeGBIF, 2013
NetherlandsPresentNativeUSDA-ARS, 2013
NorwayPresentNativeGBIF, 2013
PolandPresentNativeUSDA-ARS, 2013
PortugalPresentNativeUSDA-ARS, 2013
-AzoresPresentIntroducedUSDA-ARS, 2013
-MadeiraPresentNativeUSDA-ARS, 2013
RomaniaPresentNativeUSDA-ARS, 2013
Russian FederationPresentPresent based on regional distribution.
-Central RussiaPresentNativeUSDA-ARS, 2013
-Northern RussiaPresentNativeUSDA-ARS, 2013
-Southern RussiaPresentNativeUSDA-ARS, 2013
-Western SiberiaPresentNativeUSDA-ARS, 2013
SlovakiaPresentNativeGBIF, 2013
SloveniaPresentNativeGBIF, 2013
SpainPresentNativeUSDA-ARS, 2013
SwedenPresentNativeGBIF, 2013
SwitzerlandPresentNativeUSDA-ARS, 2013
UKPresentNativeGBIF, 2013
UkrainePresentNativeGBIF, 2013
Yugoslavia (former)PresentNativeUSDA-ARS, 2013

Oceania

AustraliaPresentPresent based on regional distribution.
-New South WalesWidespreadIntroduced Invasive Weiss et al., 2000
-QueenslandLocalisedIntroduced Not invasive Weiss et al., 2000Not important
-South AustraliaWidespreadIntroduced Invasive Weiss et al., 200020 million ha infested
-TasmaniaWidespreadIntroduced Invasive Weiss et al., 2000Most prevalent in grazing areas of Midlands
-VictoriaWidespreadIntroduced Invasive Weiss et al., 20006 million ha infested
-Western AustraliaLocalisedIntroduced Invasive Weiss et al., 2000
New CaledoniaPresentIntroduced Invasive PIER, 2013Îsle Grande Terre
New ZealandWidespreadIntroduced Invasive Webb et al., 1988

History of Introduction and Spread

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Weiss et al. (2000) speculated that M. vulgare was first introduced to Australia from Europe in a shipment of botanical specimens sent by Sir Joseph Banks in 1798. However, it was probably also taken by early settlers to Australia, the USA and elsewhere as a useful garden herb and medicinal plant (Parsons and Cuthbertson, 1992).

Ridley (1930, cited in Guertin, 2003) suspected that M. vulgare escaped cultivation in California in 1833.

Parsons and Cuthbertson (1992) suggested that many of the present infestations in Australia began in farm gardens, often when the house was abandoned, but also from dumped cuttings and garden refuse. Once M. vulgare was accessible to sheep its spread was rapid, both within a property and to new areas, as the seed-bearing burrs cling firmly to wool. This resulted in the spread of plants along roadsides and its establishment on stock camp-sites, from where it could spread further into pastures. 

Introductions

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Introduced toIntroduced fromYearReasonIntroduced byEstablished in wild throughReferencesNotes
Natural reproductionContinuous restocking
Australia Europe 1798 (?) Yes Australia’s Virtual Herbarium (2013); Royal Botanic Gardens Sydney (2004); Royal Botanic Gardens Sydney (2013); Weiss et al. (2000) Botanical specimen. Established in South Australia by 1848
New Zealand Europe 1867 Yes Cheeseman (1906); Hooker (1867) Abundant by 1906
USA Europe 1833 Yes Guertin (2003); Ridley (1930) California

Risk of Introduction

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Weiss et al. (2000) suggested that M. vulgare has probably reached its maximum potential distribution in Australia, but not its potential density. Presumably it could still become established in more countries if its seeds are deliberately or accidentally carried there.

Habitat

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In south-east Australia (New South Wales, Victoria and South Australia), M. vulgare is found in both high and low rainfall districts and shows some preference for alkaline soils (Parsons and Cuthbertson, 1992). In its native area M. vulgare grows on alkaline calcareous soils (Sagliocco, 2000, cited in Guertin, 2003).

It is first found in a new area growing along roadsides, on channel banks, sheep camps, rabbit warrens and elsewhere where bare soil is found. From such places it moves into nearby farmland, especially in degraded pasture and following droughts. In New Zealand it grows in similar habitats, including ‘open, dry pastures, rocky ground and disturbed sites such as roadsides, railways, heaps of spoil, waste places’ (Webb et al., 1988).

As in Australia, in the USA M. vulgare has been distributed throughout regions where sheep are raised (Stritzke, 1975). There it is found along fencelines from where it spreads into adjacent rangeland. Young and Evans (1986) reported that the salt desert regions of the intermountain area of the western United States were extensively grazed by sheep in the first part of the 20th century and as a result ‘virtually every old sheep bedding ground or watering point now supports the weed’.

In Britain, where it is native (although perhaps only near the south coast of England), it is locally found on down landscapes, in waste places and by roadsides (Clapham et al., 1962). 

Habitat List

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CategoryHabitatPresenceStatus
Terrestrial-managed
Disturbed areas Principal habitat Natural
Managed grasslands (grazing systems) Principal habitat Natural
Rail / roadsides Principal habitat Natural

Hosts/Species Affected

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In Victoria, Australia, the native plant species Olearia astrolabe (marble daisy bush) and Muehlenbeckia horrida (spiny lignum) are both at risk from M. vulgare infestations (Weiss et al., 2000).     

Biology and Ecology

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Genetics

2n = 34 (Heiser and Whitaker, 1948).

Reproductive biology

M. vulgare is primarily pollinated by honey bees (Apis mellifera). Mature plants can produce in excess of 20,000 seeds a year, and seeds can survive in the soil for 7-10 years (Weiss et al., 2000).

Physiology and phenology

According to Parsons and Cuthbertson (1992), most seeds germinate after autumn rains, but some germination can also take place through winter and into spring. However, according to Weiss et al. (2000), most seedlings that emerge in spring and summer do not survive their first summer. Young seedlings are not very competitive and therefore tend to germinate in bare ground, but once established they grow rapidly and can then overtop and suppress other species. Plants may or may not flower in their first year, depending mainly on soil fertility. Established plants flower over several summer months and new growth is produced each year in autumn and spring. Seedlings do not establish in dense pasture.  

Stritzke (1975) observed that fresh seeds of M. vulgare from Oklahoma, USA, showed appreciable levels of dormancy, with less than 35% germinating within 28 days at 18, 22 or 26oC, and even fewer at lower temperatures. However, after damp storage at 4oC for 1 month, 78% of seeds germinated. After 3 months of dry storage at 26oC germination increased to 80%; it took 4 months of dry storage at 0oC to reach a comparable level of germination.

Young and Evans (1986) also explored the germination of M. vulgare seeds, this time at different locations and altitudes in Nevada, USA. As before, germination of fresh seed was low but occurred most when temperatures of 10-25oC were alternated with 35-40oC. No or very little germination occurred at constant temperatures. Cool-moist stratification at 2oC for 4 to 8 weeks followed by optimum temperature regimes increased germination to over 80%.

When Lippai et al. (1996) tested the germination of M. vulgare seeds in Australia, their results were different, but they were working with seeds that had been stored dry at room temperature for between 4 months and 3.5 years. Optimum temperatures for germination (with 95-98% germination) were at constant 25o or 27oC, or alternating 25o/15oC or 30o/15oC. Lippai et al. also examined the interactions between water potential and temperature: germination ceased entirely at -1.5MPa. The conclusion was that soil moisture availability is a limiting factor for germination in Victoria, Australia. However, once mature the plants themselves seem to be able to survive dry periods.

In low rainfall (less than 400 mm annually) conditions in Australia, M. vulgare germinates mainly in autumn, can flower the following spring (September-October) and produce ripe seeds and burrs in summer (November-January); the main growth periods being spring and autumn. In higher rainfall (more than 400 mm) areas it germinates whenever sufficient rainfall occurs, and can flower throughout the year, but burrs and seeds are mainly produced in summer and again the main growth periods are spring and autumn (Weiss et al., 2000).

Weiss et al. (1999b) compared the distribution and phenology of M. vulgare plants growing in France and in Victoria, Australia. The French plants grew at lower densities, were smaller, produced much fewer seeds per plant and had a relatively tiny number of seeds in the soil seed bank compared with Australian plants. The authors postulated that the main difference between the populations was the low level of specific herbivory in Australia, although the lack of vectors for seed distribution in France and possibly higher competition from other plants may also have played a part.

Longevity

There is little information on how long plants of M. vulgare live, but that anecdotal evidence suggests that seeds can survive in the soil for 7-10 years (Weiss et al., 2000).

Population size and structure

In Wind Cave National Park, South Dakota, USA, M. vulgare populations existed in high densities (78.3-322.9 ramets/m2) and in low densities (0.1-2.2 genets/m2) throughout the National Park (Gastineau, 2012).

Nutrition

Several authors have pointed out that M. vulgare will grow on very poor soil, and it is therefore often one of the first plants to colonise eroded areas.

Associations

Since M. vulgare often occurs on bared ground, associated vegetation also prefer to establish on bare ground, or of grassland species from nearby or previous vegetation. In Europe, Weiss et al. (1999b) observed that large M. vulgare populations were very rare but were found where sheep or horse grazing occurs.

Gastineau (2012) studied the size and biology of M. vulgare populations in Wind Cave National Park, South Dakota, USA, and found that it was significantly associated with the bare ground of prairie dog (Cynomys ludovicianus) ‘towns’ and was rarely found elsewhere, and then only in other disturbed areas such as bison trails or tree falls. Associated species on prairie dog ‘towns’ included Rosa arkansana (rose), Artemisia frigida (prairie sagewort), Verbena bracteata (bigbract verbena), Lappula sp. (stickseed), Pascopyrum smithii (western wheatgrass), Hedeoma hispida (rough false pennyroyal), Aristida purpurea (purple threeawn), Descurainia sophia (herb sophia) and Tradescantia sp. (spiderwort).

Environmental requirements

M. vulgare is both drought and frost resistant and will grow in very poor soil (Weiss et al., 2000).

Climate

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ClimateStatusDescriptionRemark
Cs - Warm temperate climate with dry summer Preferred Warm average temp. > 10°C, Cold average temp. > 0°C, dry summers

Notes on Natural Enemies

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Although very few species have been found to eat or affect M. vulgare in Australia (Weiss et al., 1999b), 27 species were found to feed on it in Europe and Morocco, and some of these are now being used as biocontrol agents in Australia (see Prevention and Control).

Means of Movement and Dispersal

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Natural dispersal (non-biotic)

Water is an effective dispersing agent for the seeds. Plants can be found along water supply channels (Weiss et al., 2000).

Vector transmission (biotic)

Horses (Equus feruscaballus) are known to eat M. vulgare and pass viable seeds in their faeces (Weiss et al., 2000). The fruit or burr readily attaches to fur or wool or clothing and can in this way be spread by sheep (Ovis ovis), rabbits (Oryctolagus cuniculus), kangaroos (Macropus spp.) and emus (Dromaiusnovaehollandiae) (Weiss et al., 2000) and in North America by bison (Bison bison) (Gastineau, 2012). Shimwell (2006) lists it as a ‘wool alien’ in Britain.

Accidental introduction

In Australia, the burrs can attach to the tyres of vehicles and be spread in that way.                      

Intentional introduction

Its historical use as a medicinal herb in tea, sweets and liqueurs and as a garden herb almost certainly led to its spread to the Americas, Australia and New Zealand in the 1800s.

Pathway Causes

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CauseNotesLong DistanceLocalReferences
Hitchhiker Yes
Medicinal use Yes Yes

Impact Summary

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CategoryImpact
Economic/livelihood Negative
Environment (generally) Negative

Economic Impact

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In Australia, M. vulgare has been a declared noxious plant in parts of New South Wales, South Australia, Tasmania, Victoria and Western Australia. Plants are bitter and not preferentially eaten by livestock. Besides the plants taking up space which could be occupied by productive and palatable pasture species, M. vulgare fruits reduce the value of sheep’s wool (Weiss et al., 2000).

Environmental Impact

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In Australia, M. vulgare is regarded as an environmental weed in Victoria, South Australia and Tasmania, since it invades native vegetation there (Weeds of Australia, 2013). It can invade open bushland such as red gum, dry coastal vegetation, mallee shrubland, lowland grassy woodlands, black box woodlands, open grasslands and rocky outcrops, especially where areas have been disturbed, overgrazed or previously grazed by sheep (Weiss et al., 2013). M. vulgare does not appear to invade undisturbed native vegetation. Its unpalatability to livestock means that it is ignored in favour of other pasture species, giving it a big competitive advantage (Weiss et al., 2000).

In California, M. vulgare is less invasive on the mainland than it is on offshore islands like the Channel Islands and Catalina Island, where it forms small to large dense patches with greater than 75% cover, excluding native vegetation and altering grassland structure (Knapp and DiTomaso, 2005). On the mainland it rarely forms dense patches but can become especially common in overgrazed areas.

Social Impact

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Apart from its impact on grazing systems and the farmers they support, M. vulgare probably has little social impact.

Risk and Impact Factors

Top of page Invasiveness
  • Proved invasive outside its native range
  • Has a broad native range
  • Abundant in its native range
  • Pioneering in disturbed areas
  • Long lived
  • Fast growing
  • Has high reproductive potential
  • Has propagules that can remain viable for more than one year
Impact outcomes
  • Negatively impacts agriculture
Impact mechanisms
  • Produces spines, thorns or burrs
Likelihood of entry/control
  • Highly likely to be transported internationally accidentally
  • Highly likely to be transported internationally deliberately
  • Difficult to identify/detect as a commodity contaminant

Uses

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Economic value

M. vulgare is important for honey bees (Apis mellifera), who are the primary pollinators of M. vulgare. Seeds and herbal products of M. vulgare are still available on the internet and presumably attract some customers; however, overall it has very little economic value. In the past it was widely transported by early settlers to the Americas, Australia and New Zealand, where it was sown in gardens as a useful medicinal herb and as a flavouring for beer.

M. vulgare has a bitter taste, caused by the alkaloid marrubin, so that it is not normally palatable to livestock although, if hungry, sheep will graze it. The meat of animals forced to eat it is tainted by the strong flavour and odour, and it takes about 7 days’ grazing on clean pasture for the taint to be lost (Parsons and Cuthbertson, 1992).

Social benefit

M. vulgare was formerly valuable as a medicinal herb, grown in many home and herb gardens, but is now much less important. It is a well-known and popular herbal medicine often used as a domestic remedy for coughs, colds, wheeziness and similar ailments (PFAF, 2013). It was formerly used for treating ear and eye problems, worms, coughs, catarrh and sore throats, and was used as a laxative, sedative and a cure for poisoning. The leaves and young flowering stems are antiseptic, antispasmodic, cholagogue, diaphoretic, digestive, diuretic, emmenagogue, strongly expectorant, hepatic, stimulant and tonic. M. vulgare is a valuable pectoral, expectorant and tonic that can be safely used by children as well as adults. It is often made into a syrup or candy in order to disguise its very bitter flavour, though it can also be taken as a tea. As a bitter tonic, it increases the appetite and supports the function of the stomach. It can also act to normalize heart rhythm. The root, used in equal portions with Plantago lanceolata or P. major, is a remedy for rattlesnake bites.

However, PFAF (2013, quoting Karalliedde and Gawarammana, 2007) warned that ‘heart rhythm, blood pressure and blood glucose levels [are] affected by large doses. Avoid during pregnancy and breast feeding. Diabetes mellitus patients on allopathic medication to lower blood sugar should avoid.’

Uses List

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Medicinal, pharmaceutical

  • Source of medicine/pharmaceutical

Similarities to Other Species/Conditions

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M. vulgare can be confused with stagger weed (Stachys arvensis), red dead nettle (Lamium amplexicaule) and wild sage (Salvia verbenaca), but these other species are less hairy, their calyx tubes have five teeth or two lips, and their flowers are purple, pinkish, bluish or reddish in colour (Weeds of Australia, 2013).

Prevention and Control

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Prevention

Care should be taken in countries where M. vulgare is already present that it is not taken to new properties, especially by sheep or other livestock with fleece or hair that can carry its seeds.

Control

Seeds do not germinate in a dense, even pasture, and establishing and maintaining such pastures are important to reduce the spread of M. vulgare (Parsons and Cuthbertson, 1992).

Cultural control and sanitary measures

Established infestations should as far as possible be prevented from spreading further by taking care that machinery, vehicles or livestock do not carry seeds elsewhere. Pest animals which could carry seeds in their fur, like rabbits, should be controlled.

Physical/mechanical control

Isolated plants or very small infestations of M. vulgare should be pulled and burnt before flowering and the area checked for seedlings (Parsons and Cuthbertson, 1992). When the species is more densely established, the area should be burnt to destroy existing plants and stimulate seeds to germinate, and then ploughed, preferably in summer. Further cultivation must be repeated when germination occurs. Cultivation should be followed by the sowing of a crop or pasture appropriate for the local area. Any surviving or newly emerged plants of M. vulgare should be sprayed.

Fire kills all mature plants as well as reducing the soil seed bank by up to 80% (Weiss et al., 2000).

Movement control

Care should be taken in countries where M. vulgare is already present that it is not taken to new properties, especially by sheep with fleeces containing its seeds.

Biological control

The orange and black M. vulgare bug (Agonoscelis rutila) is often seen in large numbers on M. vulgare in Australia but does not, according to Parsons and Cuthbertson (1992), provide any worthwhile control. Weiss et al. (1999b) reported 27 insect species feeding on M. vulgare in Europe and Morocco. Five species were identified as having potential for biocontrol in Australia, including Meligethes rotroui, Phytoecia melanocephala, Carcharodes boeticus, Wheeleria spilodactylus and Chamaesphecia mysiniformis.

Two European insect species – a defoliator, horehound plume moth (Wheeleria spilodactylus), and a root borer, horehound clearwing moth (Chamaesphecia mysiniformis) (Weiss et al., 1998; 1999a) have been released in Australia. According to Weiss et al. (2000)W. spilodactylus had established successfully at over 100 locations. Both species may yet have a major impact on M. vulgare, and more potential biocontrol agents are under investigation in Australia.

Chemical control

Although selective herbicides that can be used in grass/legume pastures are few – according to Parsons and Cuthbertson (1992) MCPA is less damaging than 2,4-D to sown legumes – a number of herbicides are effective for treating individual plants or small patches. These include 2,4-D, MCPA, amitrole T, dicamba (with or without 2,4-D and MCPA), glyphosate, triclopyr and terbutryn. Diuron can be used to control seedlings in cereal crops if applied when the crop is in the 2- to 5-leaf stage. Weiss et al. (2000) added bromacil, bromacil + trichloroacetic acid, diflufenican and metribuzin to this list.

IPM

According to Parsons and Cuthbertson (1992), establishing competitive pastures is the key to preventing or minimising the problems caused by M. vulgare. Weiss et al. (2000) recommended establishing biocontrol agents of the species, carrying out pest animal control programmes (to limit the spread of seeds), controlled burning of grasslands in autumn, applying herbicides to control any surviving plants, revegetation with appropriate annual or perennial pasture species, and monitoring and redistribution of biological control agents if natural dispersal is too slow.

Control by utilization

M. vulgare apparently has a bitter taste, caused by the alkaloid marrubin, so that it is not normally palatable to livestock although, if hungry, sheep will graze it. However, the meat of animals forced to eat it is tainted by the strong flavour and odour, and it takes about 7 days’ grazing on clean pasture for the taint to be lost (Parsons and Cuthbertson, 1992).

References

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Contributors

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04/08/13 Original text by:

Ian Popay, consultant, New Zealand, with the support of Landcare Research.

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