Weed of the month – Topped Lavender
Posted on 19 December, 2024 by Lori
Lavender is a well-known plant and is often found growing in our gardens and backyards, but did you know that these plants have the capacity to become weeds? One species, Topped Lavender (Lavendula stoechas) is even a declared noxious weed in Victoria. A number of other types of Lavender also have ‘weedy’ tendencies. 
Many Lavenders originated from the Mediterranean region but there are also species that have come from India and Africa. Originally there were only a handful of lavender species, however these have cross-bred and hybridized leaving us with somewhere between 28 and 48 different species in Australia.
Their ability to grow in hot, dry conditions, coupled with their ability to invade neglected sites, disturbed bushland and low-quality areas make it especially important to keep an eye out for this plant in our natural environment. Being first introduced to New South Wales in 1957, Lavender was considered naturalised in Victoria by 1893 and declared a noxious weed by the 1920s. Topped Lavender is listed as restricted within the North Central Catchment.
A perennial shrub from the mint family, it is highly fragrant. It reproduces readily from seed but can also successfully reproduce through stem fragments. It can be quite tricky to accurately identify the species as it has a number of common names and there is also a constant supply of new cultivars arising from the nurseries. This means it can be very tricky to keep up to date with the weedy potential of this plant and tracking who the parent plants are, can be quite confusing. Even if you have not identified the type of lavender you are growing, if you have plants in your garden that are successfully reproducing by themselves, it maybe worth considering not growing these plants anymore, especially if you live near bushland.
Lavender can be quite successfully controlled through manual removal, although larger infestations can be sprayed with herbicide when actively growing, or cultivated. Consider establishing a desirable competition plant to reduce re-infestation levels.
For more information head to Castlemaine Flora website – click here and Weeds Australia – click here
The Weed of Month article is a segment from Connecting Country’s ‘Partnerships Against Pests’ project funded by Agriculture Victoria in 2024-25. Through this program, Connecting Country is working closely with local community groups, such as Landcare, to raise awareness of local pest plant and animal issues, with the aim to empower community with the skills to address these threats. The project includes seasonal awareness campaigns around key pest issues as well as workshops, and market stalls across the region. Keep an eye out for Connecting Country staff and Landcare volunteers holding weed information market stalls at Mount Alexander Shire markets over the coming months.
Photo: Castlemaine Flora
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