Harrisia cactus (Harrisia spp.) is declared noxious in the Illawarra District Weeds Authority control area (including Kiama, Shellharbour and Wollongong council areas).
The weed control class is 4. This means that:
"The growth of the plant must be managed in a manner that continuously inhibits the ability of the plant to spread and the plant must not be sold, propogated or knowingly distributed".
Description: A spiny rope-like, night-flowering perennial cacti. Forms large tangled mats 30 to 60 cm high. Stems are bright green, fleshy, jointed at 30 to 45 cm and 2.5 to 4 cm in diameter. They are ribbed length wise, each rib with 6 low, pyramidal humps, 5 to 7.5 cm apart. Each is crowned with rounded areoles of grey felted hairs, giving rise to 1 to 3 sharp spines to 35 mm long. The fruit are red, subglobular, 4 to 5 cm diameter. When ripe, fruit reveal 400 to 1000 small black seed imbedded in white pulp.
Problem: Can form dense matted thickets. They are impenetrable to stock and can cover most of the ground in an area. Seeds remain viable for 4 to 5years.
Control: Biological control may be satisfactory. Herbicides are available.
For more detailed information click here