Type of weed: Woody weed
An erect perennial shrub growing 3m x 3m. It is characterised by its woody, thorny growth. The stems are rigid, very branched and the main stems have spines up to 15cm. The long thorns are a distinctive feature.
The leaves are smooth, fleshy and up to 3.5cm long. The plant is drought resistant and in times of moisture stress can shed its leaves, making it look dead. In some locations plants can be deciduous.
Flowering generally occurs in spring and early summer, but it may occur at any time of the year provided the conditions are right.
The flowers have five petals; white with pale blue markings and are fragrant.
Fruit set generally occurs in autumn but, again, it can occur at any time of the year depending on conditions. The berries are green when young and orange-red when ripe. Each berry contains 35–70 seeds. Seeds can germinate at any time of the year if there is adequate moisture and warmth.
This plant can be confused with Native Blackthorn (Bursaria spinosa subsp. spinosa).
Spread by seed. Fruit is commonly eaten by foxes and birds. Seeds may also be spread by water, machinery and in dumped garden waste or contaminated soil.
Impact on bushland
The plant is an aggressive invader of bushland and waterways. It has an extensive, deep, branched taproot that will sucker and produce new growth if broken. Early root growth is rapid to allow seedlings to compete with other plants. It also provides habitat for native birds, so replacement planting of native species needs to occur as a follow-up to control treatments.
Lower Blue Mountains. Lower Mountains such as Glenbrook (and Cumberland Plain)
Local provenance Grevilleas, Banksias and Hakeas make great hedge plants and habitat for native birds. Spiky bushes that provided shelter and protection for small native birds include:
- Hakea teretifolia
- Lambertia formosa
- Leucopogon lanceolata
In the lower Mountains, plant Bursaria spinosa subsp. spinosa.
Council provides a tool, on its Mountain Landscapes website, to help you choose native alternative plantings. Choose your village, soil, vegetation community and the purpose of your planting, and the tool will give you suggestions.
• Seedlings can be hand pulled if all the root can be removed.
• More established small plants will need to be cut and painted using herbicide.
• Larger plants can be stem injected.
Because the berries are bird spread, it is best to treat plants before they fruit; if not bag the fruit and treat in a hot compost. Other parts of the plant can be spread to dry out off the ground and it will break down, or compost if you prefer.
For key points on these techniques: