Flora for Study 2018 ORCHIDS, Foe Alligator Weed

Can you believe Australia has more than 800 native orchid species? The elegant array of colours, scents and shapes of our orchids is so vast that they’re irresistible to many passionate gardeners.

Because of their enormous popularity, our orchids have a multitude of registered hybrids. They even have an organization dedicated to them! And they do look gorgeous in your garden.

Australian-Native-Orchids These plants are wonderful plants for semi-shaded areas. Commonly known as Dendrobiums although there has been a recent name change to Thelychitons (which is being largely ignore).

Sadly, while the more common orchids such as cymbidiums are very well known, the native orchid is one of the greatest horticultural treasures waiting to be found. They produce masses of small orchid flowers from August to October each year. Some of them are very sweetly perfumed &, if looked at closely in strong light sparkles can be seen in the petals. In spite of their delicate appearance & perfume they are tough as nails.

Epiphytes orchid

Epiphytes are orchids which attach themselves to trees or rocks. These huggers are not parasitic as you’d imagine, but use tree branches and rocks simply for support.



Swan Orchid









ALLIGATOR WEED  is a potentially devastating weed that grows in water and on land, affecting both waterways and floodplain areas. It is listed as a Weed of National Significance (WoNS).

Alligator weed has extremely vigorous growth and great tolerance of normal control measures, which makes it a major threat to wetlands, rivers and irrigation systems.

Alligator weed is considered one of the world’s worst weeds because it impacts on both aquatic and terrestrial environments. Overseas experience indicates that its potential impacts in Australia could be devastating.

Alligator weed disrupts the aquatic environment by blanketing the surface and impeding the penetration of light. Such blanketing can also impede gaseous exchange (sometimes leading to anaerobic conditions) which adversely affects aquatic flora and fauna. It also competes with and displaces native flora along river and creek banks and in wetlands.

Alligator weed has eliminated small crops and turf farming from parts of the Lower Hunter. The potential costs to irrigation farming in the Murrumbidgee Irrigation Area from the Barren Box Swamp infestation have been estimated to be $250 million a year if alligator weed remained uncontrolled.

In the Sydney Basin, alligator weed is currently threatening the turf industry valued at over $50 million annually. The vegetable industry valued at $150 million annually is also under threat in the Hawkesbury–Nepean catchment. The extraction industry in the Hawkesbury–Nepean is also under threat. This industry supplies most of Sydney’s sand, gravel and soil resources. If contaminated, the movement of these resources would be severely restricted. Sugar cane and soy bean industries are also threatened in the Richmond catchment.

Alligator weed contaminates grazing pastures and competes successfully for light and space, becoming dominant in wetter sections of pastures. Dense infestations also restrict stock access to drinking water.

In New Zealand and Australia, alligator weed is thought to cause photosensitisation in light-pigmented cattle, resulting in cancerous lesions.




Alligator weed in water.
Alligator Weed Flower
Alligator weed on land.