Bulbs that become bushland weeds

Page last updated: Thursday, 11 December 2014 - 10:13am

Please note: This content may be out of date and is currently under review.

Buying invasive bulbs

Some of the bulbs and corms listed in this article are no longer stocked by reputable nurseries, but are frequently sold at weekend markets, school fêtes, church bazaars and swap-meets, where gardeners may purchase them without knowing the environmental threat they pose.

Buying from such sources carries other risks, as pests and diseases may be present in the plants and potting mix. The same applies to gifts of bulbs and corms sent by friends or relatives living interstate or overseas — not only may the species be invasive but also the storage organs may contain insect pests or diseases.

Fortunately, Australian Quarantine and Inspection Service (AQIS) officers can detect and intercept deliveries of bulbs, corms, and even seeds by x-raying parcels from overseas.

Some bulbs and corms that are invasive in Western Australia are not environmental weeds in other states and they may feature in mail order catalogues printed there. If the catalogues are inserted in national magazines, gardeners get the impression that these plants are suitable for growing anywhere in Australia.

If gardeners cannot obtain the bulbs and corms they have read about from a local nursery, they may be tempted to order then through the internet. In this case, again, parcels containing bulbs and corms are detected when screened by AQIS. The legality of importing interstate bulbs can be checked with Quarantine WA on +61 (0)8 9334 1800.

Another pitfall for conscientious Western Australian gardeners is access to gardening books that were first written for Europe or the USA. When these are reprinted for publication in Australia, some Australian content is added but unsuitable exotics are not necessarily deleted.

Responsible gardening

Occasionally people ask why plants that can become environmental weeds are not simply banned. This is possible for plants that are not already present in Western Australia. AQIS has strict guidelines that exclude the importation from overseas of new plants that may pose a threat to either the environment or commercial crops. However, it is impractical to suggest that invasive species, which are already well-established in Western Australian gardens, can be eradicated easily. It is also very difficult to monitor casual sales outlets such as weekend markets.

Gardeners, however, can make a big difference simply by recognising invasive species and opting not to buy, grow, or exchange them, and by never dumping garden waste in the bush.

Contact information

Pest and Disease Information Service (PaDIS)
+61 (0)8 9368 3080