KC Weed of the Month

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Name of weed?

Chrysanthemoides monilifera subsp. monilifera (Boneseed)

Status

Declared weed under the Biosecurity Act 2019

CHARACTERTISTICS OF BONESEED

What does it look like?

Boneseed is a woody shrub growing to 3 metres with elongated leathery leaves. It flowers from late-winter and produces yellow flowers in clusters. The round fleshy fruit turn black when mature and contain a single smooth seed. The seed is bone coloured when dry, hence the name ‘boneseed’.

Why is it a problem?

Boneseed is a serious environmental weed and is a Weed of National Significance (WONS). It can form dense thickets several metres high which exclude most native understorey species and prevent their regeneration. In such situations the native fauna may also be affected by the loss habitat and food sources. This aggressive species has spread rapidly and is invading conservation areas in southern Australia, replacing entire ecosystems.

Where are you likely to see it?

Boneseed can invade the understorey of a range of habitats, but is particularly invasive in coastal areas from Taroona to Snug. A regional containment line has been supported by many Southern Councils in an effort to prevent further spread of this highly invasive weed. For the Kingborough municipal area, the boneseed containment line is Snug River. This means that boneseed infestations found south of Snug River and on Bruny Island are targeted for eradication.

If you see boneseed in these areas please report these sightings to Council at kc@kingborough.tas.gov.au or 03 6211 8200.

METHODS FOR REMOVING BONESEED?

By hand

Small plants and seedlings are easy to hand pull due to their shallow roots. If the plants have seeds, dispose of them by double-bagging the seed heads and disposing in general waste only, not green waste. Alternatively, plants can be left on site to break down.

Cut stump method

Cut stems as low to the ground as possible and paint neat Glyphosate herbicide on the stump within 15 seconds.

Foliar spraying

A number of herbicides are effective on boneseed. Clopyralid (eg. Lontrel) and Metsulfuron-methyl (eg. Associate) are of very low toxicity and can applied as a foliar spray to control boneseed. The addition of a wetting agent or penetrant will improve uptake of these herbicides. Cover all of the foliage with herbicide.

What is Council doing to control boneseed?

Boneseed is a weed which is targeted south of Snug River and on Bruny Island. In working towards this, Council controls boneseed using a number of methods, including cut and paint, targeted spraying and manual removal. When boneseed is identified on other land tenures, including private land, landowners are notified and advised of best practice control methods. Where necessary, Council will enforce the Biosecurity Act 2019 and require landowners to control boneseed infestations.

North of Snug River, where boneseed is widespread and abundant, infestations are prioritised to ensure the most cost effective and efficient use of Council resources.  Prioritisation is based on a number of factors, such as the size of infestations, proximity to areas of high natural values, such as bushland reserves or threatened species, and other criteria, such as impact on fire regime, recreational or aesthetic values.

There has been an in increase in community concern surrounding boneseed, particularly where infestations are highly visible, such as alongside the steep walking tracks and cliffs when viewed from our shorelines. Unfortunately, these areas are often the hardest to access and control.

In June 2023, after 15 years of successful on ground management of boneseed in the adjacent coastal reserves, Council was able to identify and secure a contractor that has the technology and capability to tackle invasive weeds in hard to access areas. Drone technology was employed to accurately target boneseed on the steep cliffs next to the Suncoast Headlands and Boronia Beach Track.  Substantial investment into contracting this new technology demonstrates Council’s commitment to the management of this invasive species for the protection of our natural areas.

For more information about Paterson’s Curse and removing it using herbicides, visit Department of Primary Industries, Parks, Water and Environment’s website: Boneseed | Department of Natural Resources and Environment Tasmania (nre.tas.gov.au)

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Name of weed?

Erica caffra (Water heath)

Status

Declared weed under the Biosecurity Act 2019

CHARACTERISTICS OF WATER HEATH

What does it look like?

Water heath is a large shrub or small tree, commonly growing to 3 metres (or taller). It has lance shaped leaves that are deep green, sometimes greyish green, up to 2 cm long. It produces small white bell-shaped flowers, covered in fine hairs, with a strong honey scent. Also known as sweet-scented heath, it is one of the few Erica species with fragrant flowers. Similar in appearance to Spanish heath, water heath can be distinguished by its wider and longer leaves, and the hairy, scented flowers.

Impacts?

Water heath is a fast-growing plant and can establish in relatively natural ecosystems. It is tolerant of a wide range of conditions including frost, fire, waterlogging, and possibly drought. Without control, water heath can spread rapidly and cause devastation to waterways and surrounding habitats. It poses a very high risk to biodiversity because of its ability to form dense thickets that smother native vegetation, as well as prevent access for land management and recreational activities. Dense infestations of water heath pose a significant fire hazard.

Where are you likely to see it?

Water heath has a limited distribution and is currently restricted to small areas on South Bruny.

If you see water heath, please report these sightings to Kingborough Council.

Methods of control?

By hand

Seedlings and small plants can be hand pulled in moist or sandy soil. Take care when removing by hand, as plants break off easily and remaining roots can reshoot. Plants should be left on site to break down.

Cut stump method

Cut stems as low to the ground as possible and paint undiluted Glyphosate herbicide on the stump within 15 seconds.

Foliar spraying

Foliar spraying can be highly effective, providing it is carefully chosen, selectively applied to small plants and regrowth, and all foliage is covered when the herbicide is applied.

Several herbicides are effective on water heath including Metsulfuron-methyl (eg. Associate), which is of very low toxicity. The addition of a wetting agent or penetrant will improve the uptake of any herbicide used.

What is being done about water heath?

Water heath is a high priority weed which is targeted throughout Kingborough. In working towards this, Council uses a number of control methods, including cut and paint, targeted spraying and manual removal.

Water heath mostly occurs on private land, but like all weeds, it has no regard for property boundaries, routinely jumping from one property to the next. In recognition of the potential impacts of this invasive species, Kingborough Council secured funding through the Weed Action Fund for a 3 year, cross-tenure weed control project on Bruny Island.

Council staff have extensively surveyed areas around known infestations of water heath and identified private properties for free weed control assistance through the grant funding. Infestations of water heath were prioritised to ensure the most cost effective and efficient use of the limited amount of funding.

Prioritisation is based on a number of factors, such as size of infestations, proximity to areas of high natural values including threatened species, and other criteria, such as impact on fire regime, recreational or aesthetic values.

The opportunity to work collaboratively with private landowners has been important to the success of the Weed Action Fund project and achieving the long-term goal of eradicating water heath from Kingborough.

For more information about Paterson’s Curse and removing it using herbicides, visit Department of Primary Industries, Parks, Water and Environment’s website:  Erica | Department of Natural Resources and Environment Tasmania (nre.tas.gov.au)

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Name of weed?

Echium plantagineum (Paterson’s Curse)

Status

Declared weed under the Biosecurity Act 2019

CHARACTERISTICS OF PATERSON’S CURSE

What does it look like?

• Paterson’s curse commonly grows to 60cm high, but it can grow up to 150cm.
• Seedlings appear in autumn and develop into a rosette in winter.
• Several upright stems are produced in late winter, followed by flowering in spring.
• Flowers are trumpet shaped; mostly purple but occasionally pink or white.

Impacts?

Paterson’s curse carries a great economic risk to Tasmania as it competes with pasture, contaminates feed and is toxic to some stock. It is estimated to cost Australia’s sheep and cattle industry $250 million every year. It also poses a threat to the environmental values of Kingborough and its spread is of great concern. Fortunately, due to limited infestations, we still have the opportunity to prevent Paterson’s curse from having the same devastating impact that mainland Australia has witnessed. Success, however, relies on all of us to play a role and do our part to stop its spread and ultimately eradicate this serious weed species.

How does it spread?

Paterson’s curse reproduces by seed which can be spread via:

• Vehicles and machinery
• Water
• Animals (livestock, birds, ants)
• On clothing and footwear
• In hay, sileage, wool, soil, and commercial seed
• Livestock can carry seed in their digestive tract or directly on their coats.

 Where are you likely to see it?

Paterson’s curse is most likely to be encountered in the Suncoast area of Blackmans Bay, however scattered infestations occur elsewhere in Kingborough.

If you see Paterson’s curse, please report these sightings to Kingborough Council.

Methods of control?

• Management of Paterson’s curse is best achieved through the application of herbicides registered for use on this weed, and in accordance with the label.
• Be aware that any disturbance to soil through physical removal or application of non-selective herbicides such as Glyphosate will encourage further germination of seeds.
• If you choose to physically remove plants either by digging out or hand pulling, ensure they are placed inside two sealed bags and disposed of in general waste.
• Do not dispose of Paterson’s curse via green waste.
• Do not slash, brushcut or mow Paterson’s curse. This will not destroy the plant and will only encourage further spread of the infestation.

 What is being done about Paterson’s curse?

Paterson’s curse is a high priority weed which is targeted throughout Kingborough. In working towards this, Council uses a number of control methods, including cut and paint, targeted spraying and manual removal.

Flowering occurs mostly in Spring, but as plants of Paterson’s curse can be found at any time of the year in all stages of growth, Council staff visit all known infestations on Council land regularly throughout year and control any plants detected.

Since 2017, Council has sent letters each Spring to all residents in the area of any known Paterson’s curse infestation as a reminder to re-inspect their property, remain watchful over the coming months and to control any plants found, including following up any previous work as required.

When Paterson’s curse is identified on other land tenures, including private land, landowners are notified and advised of best practice control methods. Where necessary, Council will enforce the Biosecurity Act 2019 and require landowners to control Paterson’s curse infestations.

Kingborough Council has fined landowners in the municipality for failing to comply with a requirement notice in relation to Paterson’s curse.

For more information about Paterson’s Curse, visit Department of Natural Resource and Environment Tasmania website:  Paterson’s Curse and Viper’s Bugloss | Department of Natural Resources and Environment Tasmania (nre.tas.gov.au)

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Name of weed?

Nassella trichotoma (Serrated tussock)

Status

Declared weed under the Biosecurity Act 2019

CHARACTERISTICS OF SERRATED TUSSOCK

What does it look like?

• Serrated tussock is a perennial grass to about 50cm high.
• The seed head is distinctive and is the best way to identify serrated tussock.
• Leaf blades have a rough or serrated texture, and while useful in distinguishing this species, is not in itself diagnostic.
• Serrated tussock leaves roll smoothly between the fingers as if cylindrical. Similar looking native grasses feel like they have flat edges.
• Leaf bases of serrated tussock are always whitish in colour, never purple.
• At the junction of the leaf and stem of serrated tussock is a short, hairless ligule. Most grasses that are confused with serrated tussock have hairy ligules.

Why is it a problem?

Serrated tussock is a highly invasive weed and many of Kingborough’s environments are vulnerable to the establishment and spread of the weed. If this occurs, our highly valued agricultural, tourism and environmental assets will be under threat. Livestock are unable to graze on the tussock, which impacts on the economic viability of farms. The species is known to dominate pastures and native grasslands in as little as a few years. This means it can have detrimental impacts on native ecosystems by threatening plant species and reducing biodiversity and habitat for native animals. Dense infestations pose a serious fire hazard with recorded burn intensities of up to 7 times greater than native grass.  Serrated tussock infestations also affect land values.

How does it spread?

Serrated tussock grows from seed, which is mainly spread by wind. Seed heads are carried along the ground and in the air and may be blown many kilometres.

Serrated tussock seeds are also dispersed by:

• moving water
• transportation of soil, gravel, and firewood
• in hay and fodder
• on machinery and equipment
• coats of livestock
• in the droppings of animals.

Where are you likely to see it?

A limited number of small, localised occurrences have been recorded across Kingborough. These are the result of accidental importation of seed in hay, soil, and gravel, or during activities such as earthworks, and mowing.

If you are planning to use a contractor to undertake landscaping or building activities, demand  their vehicles, machinery, and equipment has been washed down before entering your property, especially if they work regularly in areas known to have large  infestations of serrated tussock, such as Hobart’s Eastern Shore. If they have not washed down, do not let them enter your property. Direct them to https://nre.tas.gov.au/Documents/Washdown-Guidelines-Edition-1.pdf, where they will find the appropriate washdown directions for various equipment, and the associated washdown ledger. Once this has been completed, then work on your property can commence. This is a legal obligation of the contractor.

Likewise, avoid buying products such as soil, gravel, and hay from contaminated areas. Wherever possible buy certified weed-free products.

If you see serrated tussock, please report these sightings to Kingborough Council.

Methods of control?

• Preventing the invasion of serrated tussock is the cheapest and most effective means of control. Establish and maintain healthy, vigorous pastures and native vegetation as these are less prone to invasion than bare patches. Learn how to identify serrated tussock, regularly check for it and act immediately to remove it.
• Individual serrated tussock plants or small infestations can be chipped out with a mattock. If you choose to physically remove plants, ensure that they are placed inside two sealed bags and disposed of in general waste.
• Do not dispose of serrated tussock via green waste.
• Depending on the time of year and situation, chemical control of serrated tussock can be achieved by spot spraying with glyphosate or flupropanate. Organic herbicides such as nonanoic acid can also be effective.

What is being done about serrated tussock?

Serrated tussock is a high priority weed which is targeted throughout Kingborough. In working towards this, Council uses a number of control methods, including targeted spraying and manual removal.

Council staff visit all known infestations on Council land regularly throughout year and control any plants detected.

In early 2022, a significant roadside infestation of serrated tussock was discovered at Apollo Bay on Bruny Island. The environment and land uses of North Bruny make it particularly vulnerable to the establishment and spread of serrated tussock. Council immediately created a management zone for Apollo Bay to contain the infestation. This included a temporary halting of roadside slashing and Council earth works in the area, installation of signage, engagement of surrounding property owners, conducting a community information session, and funding a cross-tenure eradication program.

The eradication program includes free surveying of private land using Council staff and Fonzie the conservation detection dog to sniff out isolated plants missed during primary control. Remaining serrated tussock plants were manually removed.

A single serrated tussock plant can produce over 100,000 seeds each year and often the presence of the weed is not known before infestations are widespread and are causing significant impacts. The use of the conservation detection dog is critical in locating isolated serrated tussock plants in a landscape dominated by similar-looking native tussock grasses.

For more information about serrated tussock, visit Department of Natural Resource and Environment Tasmania website:

https://nre.tas.gov.au/invasive-species/weeds/weeds-index/declared-weeds-index/serrated-tussock