Description
Heather is an evergreen perennial shrub that grows to about 50 cm high in Australia. In its native northern hemisphere habitat plants have been recorded up to 180 cm high. In exposed or wet conditions, Heather may take on a prostrate form but the most common form is an erect shrub. Its stems can be ascending, erect or decumbent, and are densely hairy when young. The leaves of Heather are small, 1.5-3.5 mm long and hairless (except for the presence of a few hairs on the leaf edge). They are green when young, turn brown as the plant matures and are arranged along the stems in four, sometimes tightly overlapping rows.
The flowers are small and consist of four petals and four sepals of similar size and colour. The flowers begin as a purple colour (flower colour ranges from white through to purple), but soon become papery and brown. Although borne singly, they are clustered towards the ends of long shoots and form long, narrow, raceme-like inflorescences. The fruits are densely covered in short white hairs and are enclosed within the incurved, persistent, papery sepals. The seeds are reddish-orange, oblong and about 0.5 mm long. The root system is mat-forming and fibrous.
For further information and assistance with identification of Heather contact the herbarium in your state or territory.
Distribution:
Heather is widely grown as an ornamental in south-eastern Australia. However, it is only known to be naturalised in Tasmania. Specimens held by the Tasmanian Herbarium indicate that it has been recorded as naturalised near Lake Augusta in the Central Highlands, near Meander in the state’s north, and south of Hobart in Kingston and on Bruny Island. Recent surveys conducted in Tasmania recorded several small naturalised infestations at both Kingston and on Bruny Island. It was not rediscovered in Tasmania’s Central Highlands nor at Meander.
Heather is also naturalised in New Zealand, Finland, Canada and western United States.
Habit:
Shrub
Key points:
- Heather (Calluna vulgaris) is tolerant of a wide range of habitats that occur in Australia, the most fragile being the alpine regions of New South Wales, Australian Capital Territory, Victoria and Tasmania.
- Heather has a limited weedy distribution in Australia and has not been discovered naturalised outside of Tasmania.
- A large persistent seedbank of easily spread seed helps Heather to rapidly invade new areas.
- As it can potentially be eradicated before it becomes widely established, any new populations should be reported to your local council, or state or territory weed management agency.
- Heather has become a serious weed in New Zealand where it is dominant in Tongariro National Park World Heritage Area.
How it spreads:
Reproduction of Heather occurs primarily via seeds. Pollination occurs by various means including bees, insects and wind. Seed production can be prolific, with mature plants being estimated at producing up to 158 000 seeds per year. The viability of Heather seed is very long and, in some instances, thought to be over 100 years. Dispersion of Heather seed can occur by wind carrying the small, light seeds, sometimes up to several hundred metres from parent plants. Seed may also by spread by running water and by adhering to people, vehicles, machinery and animals.
Heather is also capable of reproducing by stem layering, i.e. the production of roots from low growing stems at the base of the plant. This occurs most commonly in moist habitats where there is an accumulation of moss and leaf litter.
Where it grows:
Heather is suited to dry and nutrient poor conditions. It is also frost hardy and can grow in wet conditions. In its native region, it exhibits a wide climatic tolerance and can be found growing at altitudes ranging from sea level through to nearly 2700 m. It generally grows in open habitats and prefers acidic soils. It is a component of many different vegetation types, especially grasslands, lowland and upland heath, moors and bogs, open woodland, sand dunes and partially stabilised scree.
Under some circumstances, the regeneration and dominance of Heather is encouraged by fire, which promotes vigorous growth of seedlings and regrowth from old stems.
However, severe fires may lead to a substantial depletion of soil stored seed and, in some cases, may completely destroy the seed bank. Many western European heaths dominated by Heather were once forested areas. Clear-felling of the forest has paved the way for heathlands that have been maintained by burning at regular intervals, principally to maintain habitat for grouse and sheep.
In Tasmania, Heather has been recorded in various different habitats including alpine vegetation in the Central Highlands, weedy roadside vegetation in highly productive inland pastoral areas, and on poor pasture and roadsides on sandy soils near the coast.
Flower colour:
White, Purple, Pink
Distribution map:
Impacts:
Heather is on the Alert List for Environmental Weeds, a list of 28 non-native plants that threaten biodiversity and cause other environmental damage. Although only in the early stages of establishment, these weeds have the potential to seriously degrade Australia’s ecosystems.
Heather has the potential to be a significant environmental weed in temperate Australia and could invade a variety of communities in lowland and upland areas, especially after disturbance such as fire or clear felling. Overseas, it has transformed tussock communities and invaded a variety of vegetation types, including native heaths, grasslands and open forest. Each of these vegetation types exists in Australia and some are particularly vulnerable. In addition, the plant can be expected to change fire regimes in natural ecosystems by altering the nature of fuel loads. It may also provide habitat for pest animals such as rabbits.
Heather is a significant weed in New Zealand where it is especially problematic in the North Island’s Tongariro National Park World Heritage Area. It was intentionally introduced to the park in 1912, and it now has the distinction of being the Park’s most widespread and invasive weed. It is the dominant cover in around 1000 ha and is present in another 25 000 ha.
The economic impact of Heather in Australia is mostly relevant to natural areas and roadsides, where its establishment would lead to greater cost burdens associated with control and removal. It may also have some impact on eco-tourism values. Whilst unlikely to invade cultivated land or well-managed pasture, incursions in unimproved pasture may lead to reduced profitability.
Mature Heather is highly competitive by virtue of its wide environmental tolerance, high reproductive capacity and its ability to form dense canopies that exclude other species. It is thought that Heather releases allelopathic compounds that inhibit growth of surrounding plants, particularly trees .
Origin:
Heather is a cool temperate, oceanic and sub-oceanic species that is native over much of Europe, with only outlying populations in south-eastern Europe. It is also native in northern Africa, the Azores and the Madeira Islands.
History: Heather is listed in an 1899 Tasmanian Nursery catalogue. The first reference of it being a weed in Australiait as an occasional garden escape in Tasmania, found on acid sands in Kingston and on Bruny Island. Records held indicate that the species was naturalised in Tasmania’s Central Highlands by 1966 where it was probably introduced during the 1920s by Scottish immigrants working on hydro-electric schemes in the area.
From a total of more than 1000 recorded cultivars, approximately 30 are available in Australia through the nursery trade.
