Giant Reed

Arundo donax

Family: Poaceae

Type of weed:

Noxious Weed Class 4. (See more noxious weeds).

Flowering Months: ,

Description

Giant Reed is a tall bamboo like perennial reed that grows to 3–6 m in height, but up to 10 m high under ideal conditions.

Leaves are 30–100 cm long, 2–7 cm wide and wrap around the stem. Leaves are generally green but variegated cultivars have been developed for garden use.

It flowers in late summer, bearing upright, feathery plumes 40–60 cm long.

Fruit consists of large feathery grass seeds that are rarely fertile.

Don’t confuse with…

Giant Reed can be confused with the native Phragmites australis, a smaller plant with much narrower stem and not clumped.

Dispersal

Spreads vegetatively from broken sections of rhizomes (roots) and stems, which are readily carried by floodwater. The rhizomes are tough and fibrous and form knotty, spreading mats that penetrate deep into the soil up to 1 m.

Impact on bushland

Large dense clumps of the reed spread out to form a forest of tall woody stems that suppress all other vegetation and block water flows. The reed can cover large areas in favourable conditions.

Distribution

, . Mainly the Lower Mountains, especially Blaxland, Warrimoo, Glenbrook.

Alternative planting

Native plants

Tall native rushes and sedges such as:

  • Common rush (Juncus usitatus)
  • Bulrush (Typha orientalis, or T. domingensis)
  • Spiny Headed Mat Rush (Lomandra longifolia)
  • Red Fruited Sword Sedge (Gahnia sieberiana)

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.

There are native nurseries in several Blue Mountains villages, including Glenbrook, Lawson and Katoomba. Please also ask at your favourite local nursery.

Control

  • Very small amounts can be dug up. Remove the rhizome if digging the plant out. Repeated treatment is required.
  • Cut and paint every stem with herbicide; scrape and paint rhizomes. Follow up treatment is required. Either cut and paint any sprouting stems, or spot spray leafy regrowth before it reaches 1.5 m.

Whichever treatment is used, avoid over-clearing of established clumps on drainage lines. Remove the clumps gradually and replace with suitable native species to hold the soil.

For more info

For key points on these techniques:

Noxious Weed Class 4

Locally Controlled Weeds

Characteristics: Class 4 noxious weeds are plants that pose a threat to primary production, the environment or human health, are widely distributed in an area to which the order applies and are likely to spread in the area or to another area.

Control objective: Minimise the negative impact of those plants on the economy, community or environment of NSW.

Example control requirements: The growth of the plant must be managed in a manner that reduces its numbers, spread and incidence, and continuously inhibits its reproduction. The plant may not be sold, propagated or knowingly distributed.

NSW Noxious Weeds Act 1993

Refer to the NSW Department of Primary Industry’s Noxious and Environmental Weed Control Handbook.