Tree heath (E. arborea), Berry heath (E. baccans), Water heath (E. caffra), Winter heath (E. carnea), Dorset heath (E. ciliaris), Bell heather (E. cinerea), Bicolored heath (E. discolor), Irish heath (E. erigena), Erica glandulosa, Erica holosericea, Spanish heath (E. lusitanica), Erica melanthera, Angled heath (E. quadrangularis), Besom heath (E. scoparia), Corsican heath (E. terminalis), Cross-leaved heath (E. tetralix), and Cornish heath (E. vagans)
Image: Besom heath (E. scoparia),
© M Baker, Tas. Herbarium.
What are Erica
These seventeen Erica species are declared weeds under the Tasmanian Biosecurity Act 2019 and associated Regulations.
These Erica species are known to be environmental and pasture weeds.
Their importation, sale and distribution are prohibited in Tasmania.
Seven declared Erica species are currently known to have populations in Tasmania.
How to identify Erica
The genus Erica, (heaths, heathers or Ericas), are commonly believed to be native plants as they have a similar shape and size to native heaths with their stiff, narrow leaves. In winter and spring, they may be covered in flowers, making them popular for the cut-flower industry.
Features that make Ericas attractive as garden plants also contribute to their weediness in the higher rainfall districts, being hardy, fast growing, long lived and will grow in infertile native soils. Prolific seed production increases their capacity to spread along roadsides and into bushland.
All are perennial (long-lived) shrubs, growing to a height of between 1.5 to 2 metres, and occasionally reaching 3.5 metres. Stems are woody and brittle, with narrow leaves that are opposite or in whorls of 3 or 4.
Flowers are either bell-shaped, tubular or globular with 4 lobes, and fruits that are capsules containing numerous small seeds which are released when flowering finishes and the flowers have browned off.
Erica seeds are dispersed short distances by gravity, water, wind, vehicle draught, slashing and soil movement. Long distance dispersal is generally a result of human activity such as planting in gardens, commercial cultivation, or inadvertent transport of soil containing seeds to new locations.
Roots are fibrous, and the plant readily breaks off near the base, often re-growing quickly from the broken stump.
Australian heaths were formerly in the family
Epacridaceae but are now in the expanded family
Ericaceae as are Erica species. Native heaths in the subfamily
Styphelioideae that could be confused with Erica in southern Australia generally have 5 petals rather than 4, and stiff leaves that are alternate instead of whorled or opposite.
In 2005
Erica arborea in Tasmania, (and
Erica lusitanica in Victoria), were nominated amongst the 10 most serious weedy garden plants currently for sale. Some Erica, (including
Erica arborea), are known to form dense thickets in bushland that dominate the understorey and can alter the composition and diversity of native plant communities.
For further information or help in identifying Erica species, refer to the
Weed Management Guide - Spanish Heath and other Erica Species, published by the Commonwealth of Australia. If you are still in doubt about the weed you are dealing with, contact Biosecurity Tasmania on 03 6165 3777 for help.
Image above left: Tree heath (E. arborea) branches and flowers, photo: © J Martin, (Wikimedia).
Image above right: Berry heath (E. baccans) in bushland, photo: © A Massyn, (Wikimedia).
Image above left: Bicolored heath (E. discolor) with flowers, photo: © Andrew Massyn, (Wikimedia).
Image above right: Besom heath (E. scoparia) infestation in Northern Tasmania, photo: M Smith, NRE Tas.
Erica in Tasmania
Erica is a genus of around 820 species of evergreen shrubs and sometimes small trees. They do not occur naturally in Australia, but have been introduced here almost exclusively as garden plants.
Many Erica species have been introduced to southern Australia, with more than 12 now recorded as having escaped from cultivation to become widespread and well established weeds in native vegetation; ; eg.,
Erica arborea is common in the southeast and
Erica baccans is also established in the west, while
Erica lusitanica has been recorded as naturalised in Tasmania decades.
The potential distribution of most Erica in Australia is largely unknown. Worldwide, most occur within a Mediterranean or temperate climatic regime in soils of relatively low fertility. Correspondingly, most of the cultivated Ericas prefer acid to neutral soils although some will tolerate a wider range of soil pH.
In southern Australia, Erica species generally occur in regions with an average annual rainfall of 600 mm or more, including heathland, forest and woodland, along drainage lines and in coastal vegetation. They have the potential to spread locally and to new regions if planted or inadvertently transported, particularly in districts with relatively high winter rainfall.
Climatch assessments for these seventeen Erica range from moderate through to very high climate suitability for Tasmania.
The seven Erica species currently known to have populations across Tasmania are: Tree heath (E. arborea), Berry heath (E. baccans), Water heath (E. caffra), Bicolored heath (E. discolor),
Erica holosericea, Spanish heath (E. lusitanica), and Besom heath (E. scoparia).
Erica are commonly found on degraded pastures, neglected areas and roadsides. They also invade native vegetation types including wet forest, dry forest, grassland and riparian (stream-side) areas, generally (but not always) where there has been some soil disturbance.
Erica in pastures can reduce productivity, while in native bushland dense infestations can replace native species.
Erica also increases the fire hazard risk as it is extremely combustible.
Image above left & centre: Water heath (E. caffra) &
Erica holosericea, photos: © Stefan Dressler, African plants - A Photo Guide.Image above right: Spanish heath (E. lusitanica) in flower, Forest & Kim Starr, (Wikimedia).
Legal status of Erica in your area
The legal responsibilities of landholders and other stakeholders in dealing with Erica are laid out in the
Statutory Weed Management Plan for Erica.
For details regarding distribution of Erica species, including whether your area falls in an eradication (‘Zone A’ municipality), or containment (‘Zone B’ municipality), refer to the Tables and information provided in Section 12, ‘Management of Erica by municipality’, in the
Statutory Weed Management Plan for Erica.
More information
Erica Control Guide
Dispose of removed material carefully to avoid regeneration: burn if possible, otherwise pile where the plants won't stem layer; Follow-up your initial control attempt: follow-up is essential to eradicate Erica.
| Don't slash flowering plants - this will spread the seed; Don't rely on slashing to eradicate Erica - slashing can worsen an infestation; Don't rely on burning to eradicate Erica - burning will worsen an infestation; Don't rely on one attempt at control: follow-up is essential to eradicate Erica.
|
Spread of Erica
Erica reproduces by seed and stem layering. Seed is dispersed by wind and water, by slashing, and in soil and mud.
Layering occurs where stems contact moist soil and send down roots. Erica is also capable of shooting from broken stems and roots.
See the
Washdown Guidelines for Weed and Disease Control for detailed information on how to wash-down equipment and personnel to reduce the chance of spreading Erica.
Physical removal
Seedlings or small plants can be hand-pulled or dug out, taking care to remove as much of the root system as possible.
The material should be disposed of safely, either by burning where appropriate, or piling plants where they cannot layer.
If plants are in flower, care should be taken to prevent accidental seed dispersal during disposal.
Large plants can have very extensive root systems, and digging out or mechanical removal may result in soil erosion. Alternative control options should be considered.
Slashing can reduce the amount of seed produced if undertaken prior to flowering, but will not kill plants. Slashing can result in more root development and low growth, making later control more difficult.
Slashing during or soon after flowering will spread seeds and should not be undertaken.
Weed matting
Weed matting can kill Erica and can achieve a 100% kill after 45 weeks.
Cultivation
Cultivation can be used to control Erica in infested pasture.
Cultivation must be undertaken regularly until the plants are no longer re-sprouting from root fragments. The establishment of competitive pasture species will help reduce Erica regeneration.
Single or infrequent cultivation will make the problem worse, and require follow up control of regrowth and seedlings.
Revegetation
Erica plants are not susceptible to shading, so the establishment of competition is not an effective means of control.
However, where Erica has been removed, re-establishing native vegetation or pasture species can reduce seed germination; (seeds of some Erica species such as
Erica arborea will not germinate in shade).
Re-establishing native vegetation is also useful in stabilising soil and reducing erosion.
Soil improvement
Erica species prefer acid soils. Applying lime to infested pasture can reduce regeneration, but will not eradicate the weed by itself.
Lime can harm native plants and is not suitable for the control of Erica in native vegetation including native grasslands.
Burning
Erica species are well adapted to fire and are not killed by burning, which is likely to make an infestation worse.
Grazing
Grazing by sheep can provide some control in moderately infested pastures. Sheep prefer the softer growing tips which reduces of flower production.
However grazing alone will not eradicate an infestation.
Chemical control
Herbicides for Control of Erica Species
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