(Also known as Calla Lily)
Type of weed: With underground regrowth structures
A clump-forming, perennial herb growing to 1.5m high with a thick underground stem (rhizome).
The large arrowhead-shaped leaf blades are glossy dark green to somewhat dull, leathery in texture, with a prominent midrib and a tip that is bent downwards or curls towards the underside of the leaf.
The arum-type flower structure has a central spike with tiny, tightly packed pale yellow to orange-yellow flowers. This is surrounded by a white to ivory (or green) funnel-like bract with a pointed, recurved tip. It flowers winter to summer.
Fruit is an oval, yellowish berry about 1cm in diameter.
Arum Lily is poisonous to stock and to children. If swallowed it causes dangerous swelling of the mucous membrane of the mouth and throat. Skin contact may cause eczema.
Arum Lily spreads by both seed and root fragments. There may be 50 – 500 seeds per flower head. The seeds germinate readily, but do not usually remain viable for more than about four months. The seeds are spread by water, birds, foxes, contaminated soil and in dumped garden waste.
Impact on bushland
Arum Lily invades native vegetation, forms thick, dense clumps and achieves dominance along watercourses and swampy habitats. The dense clumps crowd out native species affecting the biodiversity of natural areas, especially by replacing the native understorey. In wet, swampy habitats it impedes water flow.
Lower Blue Mountains. Hazelbrook, Woodford, Springwood, Winmalee, Warrimoo and across the Eastern Escarpment.
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.
- Hand remove
- Remove flowers, fruit, pods or seeds
- Manually remove bulbs, corms and tubers
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.
- 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.
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.
Remove seeds, pods or fruit
Gently remove any seeds, pods or fruit and carefully place in a bag.
Note: Herbicides that may be used for this weed include Fluroxypyr, Glyphosate, Metsulfuron methyl.
Please consult the Herbicide page of this website to help you decide whether to spray, how to do it safely and more.
Extra considerations for weeds with underground reproductive structures
- Further digging may be required for plants with more than one tuber. Some bulbs may have small bulbils attached or present in the soil around them. These need to be removed. It may be quicker and more effective to dig weeds out.
- Learn and understand how the herbicide works. For bulb and corm species the most effective time is after flowering and before fruit has set.
Specific control tips for this weed
Seedlings can be removed by hand. Removal of old plants is more difficult. Remove all roots and tubers (vegetative propagules).
Treat plants before they set seed and cut off the flowers to prevent spread by birds.
Successful weed control requires follow-up treatments after initial treatment. Arum lily can take several years to eradicate due to its large, hardy root system. Weed treatment should be repeated over several years to run down the plant’s root system.
For key points on these techniques:
Local Priority Weed
- 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.