(Also known as Mist Flower)
Ageratina riparia
Family: Asteraceae
Type of weed: Woody weed
Flower colour(s): White
Priority Weed Local Priority Weed. (See more weeds of the Local Priority Weed class.)
Flowering Months: January, February, December
Description
Mistflower is a straggly perennial growing to 1 m with lanceolate leaves.
It has delicate white tubular flower heads in summer.
A mature plant can produce 10,000 to 100,000 seeds per year. Seeds are 2 mm long with tufts of fine white hair.
Mistflower is almost identical to Crofton Weed but with more delicate flowers. Crofton Weed is more erect and has trowel-shaped leaves.
Dispersal
Seed is dispersed by wind and water over long distances.
Impact on bushland
Mistflower spreads easily along creek lines frming dense stands than can exclude other plants.
Distribution
Lower Blue Mountains, Upper Blue Mountains. In sheltered, wet areas such as creeklines.
Alternative planting
Native plants
Alternative plantings to hold soils on creekbanks or stormwater drainage lines include ferns, sedges and rushes such as:
- Fishbone Water Fern (Blechnum nudum)
- Prickly Rasp Fern (Doodia aspera)
- Common Ground Fern (Calochlaena dub)
- Broad Rush (Juncus planifolius)
- Common Rush (Juncus usitatus)
- Tall Sedge (Carex appressa)
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
- Hand remove
- Spray
- Cut and paint
Manual control
Hand remove
Grasp stem at ground level. Rock weed backwards and forwards to loosen roots, then pull out gently. Carefully tap the roots to dislodge attached soil. Replace disturbed soil and pat down.
Considerations
- Leave weeds so that roots do not make contact with soil; on a rock, for instance. A small amount of debris may be hung in a tree or removed from the site.
- Vary the position of your body to avoid fatigue when removing plants by hand over extended periods.
Chemical control
Note: Herbicides that may be used for this weed include Glyphosate.
Spraying
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
- Most plants can be hand pulled easily, particularly when the ground is moist. Make sure all roots are removed. When hand removal is not possible, or there is a concern about destabilising creek banks, then cut and paint the plant.
- Spray low, dense patches.
Remove and dispose of flowers. Cut material can spread out to dry off the ground. Once dead, the material will decompose in place. It is best to treat Mistflower before it flowers, to avoid spreading seeds.
Refer to the NSW Department of Primary Industry’s WeedWise website for more information.
For key points on these techniques:
Local Priority Weed
Control measures:
- The plant should be fully and continuously suppressed and destroyed.
- Plants under 4 metres in height should be fully and continuously suppressed and destroyed.
- The spread of this plant should be adequately contained to prevent spread impacting on priority assets. Weed notices will only be issued for these weeds under special circumstances.
