Type of weed: Grass
Flower colour(s): Silky
Priority Weed Regional Priority Weed. (See more weeds of the Regional Priority Weed class.)
Flowering Months: January, February
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.
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.
Lower Blue Mountains, Upper Blue Mountains. Mainly the Lower Mountains, especially Blaxland, Warrimoo, Glenbrook.
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.
- Manually remove bulbs, corms and tubers
- Cut and paint
Move leaf litter away from base of plant. Dig down next to the stem until the bulb or tuber is reached. Remove plant and carefully bag the bulb or tuber.
Note: Herbicides that may be used for this weed include Glyphosate.
Please consult the Herbicide page of this website to help you decide whether to spray, how to do it safely and more.
Cut and paint
Useful for small to medium sized woody weeds up to 10 cm in diameter.
Make a horizontal cut as close to the ground as possible with secateurs or loppers, and immediately apply concentrated Glyphosate to the exposed stump surface. Do not allow the surface to get covered with soil.
Specific control tips for this weed
- 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 key points on these techniques:
Regional Priority Weed
- The plant should be eradicated from the land, which must be kept free of the plant.
- The plant should be fully and continuously suppressed and destroyed.