Invasive Plants

There are many garden plants that have jumped the backyard fence, and invaded our bushland.
Watsonia and freesias are pretty as a picture in spring, but replace naturally occurring species. Not
only the bulbs and perennials, even Australian native species such as wattles and sollya have proved
a problem in some areas of Australia.
Each locality has its own collection of environmental weeds and it is important that we do not plant
species that have proved to be escapees in our local area.
At Zanthorrea, we take this issue seriously and have put together a list of “no-grow” plants and also
a list of “not recommended near natural bushland” species. We welcome feedback and comment
to [email protected].
The following is our policy on invasive plants:

Policy on Environmental weeds, January 2001
(updated August 2005)

Notes:

1. We acknowledge that some garden plants have the potential to become weeds in our native
   bush.
2. A weed is a plant growing where it is not wanted. Generally we consider that all introduced plants
   that establish themselves outside cultivated areas are weeds.
3. Some plants that are weeds in our region pose little or no threat in other drier areas. Some plants
   that are weeds in wetter climates may not be able to survive our harsh summer climate.
4. It would be unrealistic to produce a banned list for the whole of Australia due to differences in
   climate and conditions. There is a list of “Weeds Of National Significance” (WON) Plants on this
   list are not grown in WA.
5. Some weeds are “Declared Plants” (refer to WA Agricultural Dept) and are banned in WA.

Is it possible to predict which plants may be a problem?

Generally the following may become weeds:
• Plants from drier areas of the world (Mediterranean, Mexico, South Africa, Chile, California)
• Plants with copious amounts of seeds, especially berries.
• Plants that colonise disturbed ground, such as agricultural weeds.
• Plants with effective seed dispersal methods such as wind or animals.

The “Outlaws” (We don’t sell these.)

• Acacia baileyana
• Acacia iteaphylla
• Acacia longifolia
• Acacia melanoxylon
• Acacia pycnatha
• Acacia dealbata
• Acacia decurrens
• Acacia podalyrifolia
• Zantedeschia aethiopica (Arum lily) (DP)
• Bulbs such as watsonia, sparaxis, jonquils,
freesia, ixia, babiana, ornithogalum, tritonia.
• Grasses which are not native to our area,
such as juncus, cortaderia (DP) , pennisetum,
typha (bullrush)
• Schinus terebinthefolia
• Vinca major (periwinkle)
• Ascelpias (cottonbush)
• Ipomoea species (cairica, indica)
• Cytisus prolifera (now Chamaecytisus
palmensis) – tree lucerne
• Genista (broom)
• Psoralea pinnata
• Robinia pseudoacacia (thorny suckers and
many seeds)
• Lavatera arborea (tree mallow)
• Melia azadarach (cape lilac)
• Leptospermum laevigatum (coastal or
Victorian tea-tree)
• Oxalis species
• Cotoneaster
• Salix babylonica (weeping willow)
• Datura
• Hedera helix
• Polygala myrtifolia
• Podalyria sericia
• Tradescantia spp
• Lonicera japonica
• Crocosmia spp
• Thunbergia grandiflora
• Oenothera (everning primrose)
• Lantana camara
• Lavendula stoechas (spanish or italian
lavender)
• Brachychiton populneus
• Limonium (statice)
• French lavender