Horehound (Marrubium vulgare)

Profile

Impact

Horehound infestations are extremely hardy once established, preventing desirable species from growing. The seed capsules cling to wool and clothing and may cause considerable matting of sheep fleeces. 

Description

Horehound is a bushy perennial plant, 30 to 80cm high, with deeply crinkled leaves.

Habitat

Horehound commonly occurs throughout Australia along fence lines, road sides, channel banks, around buildings, sheep camps and neglected areas. 

References

Cunningham GM, Mulham WE, Milthorpe PL and Leigh JH (1992). Plants of Western NSW. 

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Control

Chemical and biological controls are available for horehound.

Biological control

Two moths - a plume moth (Wheeleria spilodactylus) and a clear wing moth (Chamaesphecia mysiniformis) have been released against horehound in NSW. The plume moth has a significant impact on the weed, and the clear wing moth has a good impact, but is more difficult and time consuming to rear. 

Herbicide options

WARNING - ALWAYS READ THE LABEL
Users of agricultural or veterinary chemical products must always read the label and any permit, before using the product, and strictly comply with the directions on the label and the conditions of any permit. Users are not absolved from compliance with the directions on the label or the conditions of the permit by reason of any statement made or not made in this information. To view permits or product labels go to the Australian Pesticides and Veterinary Medicines Authority website www.apvma.gov.au

See Using herbicides for more information.


2,4-D LV ester 680g/L (Estercide® Xtra)
Rate: 1.7 to 3.3 L/ha
Comments: Boom spray application for seedlings from late autumn to early spring
Withholding period: 7 days
Herbicide group: I, Disruptors of plant cell growth (synthetic auxins)
Resistance risk: Moderate


Dicamba 500 g/L (Kamba® 500)
Rate: 80 mL in 100 L of water
Comments: High volume spot spray.
Withholding period: 7 days.
Herbicide group: I, Disruptors of plant cell growth (synthetic auxins)
Resistance risk: Moderate


Dicamba 500 g/L (Kamba® 500)
Rate: 1.2 L/ha
Comments: Boom spray.
Withholding period: 7 days.
Herbicide group: I, Disruptors of plant cell growth (synthetic auxins)
Resistance risk: Moderate


MCPA 500 g/L (Various products)
Rate: 3 L per Hectare
Comments: Boom spray application
Withholding period: 7 days.
Herbicide group: I, Disruptors of plant cell growth (synthetic auxins)
Resistance risk: Moderate


Picloram 100 g/L + Triclopyr 300 g/L + Aminopyralid 8 g/L (Grazon Extra®)
Rate: 350 mL in 100 L of water
Comments: Apply as foliar spray pre-flowering
Withholding period: Where product is used to control woody weeds in pastures there is a restriction of 12 weeks for use of treated pastures for making hay and silage; using hay or other plant material for compost, mulch or mushroom substrate; or using animal waste from animals grazing on treated pastures for compost, mulching, or spreading on pasture/crops.
Herbicide group: I, Disruptors of plant cell growth (synthetic auxins)
Resistance risk: Moderate


Triclopyr 300 g/L + Picloram 100 g/L (Grazon® DS)
Rate: 350 mL in 100 L of water
Comments: Apply as a foliar spray pre-flowering.
Withholding period: Nil.
Herbicide group: I, Disruptors of plant cell growth (synthetic auxins)
Resistance risk: Moderate


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Legal requirements

The content provided here is for information purposes only and is taken from the Noxious Weeds (Weed Control) Order 2014 published in the NSW Government Gazette, detailing weeds declared noxious in New South Wales, Australia, under the Noxious Weeds Act 1993. The Order lists the weed names, the control class and the control requirements for each species declared in a Local Control Authority area.

Area Class Legal requirements
Albury 4 Locally Controlled Weed
The growth of the plant must be managed in a manner that continuously inhibits the ability of the plant to spread
Central Murray County Council 4 Locally Controlled Weed
The growth of the plant must be managed in a manner that continuously inhibits the ability of the plant to spread
Cootamundra-Gundagai 4 Locally Controlled Weed
The growth of the plant must be managed in a manner that continuously inhibits the ability of the plant to spread only in the area formerly known as Cootamundra Shire Council
Federation 4 Locally Controlled Weed
The growth of the plant must be managed in a manner that continuously inhibits the ability of the plant to spread only in the area formerly known as Urana Shire Council
Greater Hume 4 Locally Controlled Weed
The growth of the plant must be managed in a manner that continuously inhibits the ability of the plant to spread
Lockhart 4 Locally Controlled Weed
The growth of the plant must be managed in a manner that continuously inhibits the ability of the plant to spread
Murray River (formerly Wakool) 4 Locally Controlled Weed
The growth of the plant must be managed in a manner that continuously inhibits the ability of the plant to spread
Murrumbidgee 4 Locally Controlled Weed
The growth of the plant must be managed in a manner that continuously inhibits the ability of the plant to spread
Snowy Monaro Regional 4 Locally Controlled Weed
The growth of the plant must be managed in a manner that continuously inhibits the ability of the plant to spread
Snowy Valleys 4 Locally Controlled Weed
The growth of the plant must be managed in a manner that continuously inhibits the ability of the plant to spread only in the area formerly known as Tumbarumba Shire Council
Wentworth 4 Locally Controlled Weed
The growth of the plant must be managed in a manner that continuously inhibits the ability of the plant to spread

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For technical advice and assistance with identification please contact your local council weeds officer.
For further information call the NSW Invasive Plants and Animals Enquiry Line on 1800 680 244 or send an email to weeds@dpi.nsw.gov.au

Reviewed 2016