Quick Facts

Quick facts

• Bulbil Watsonia (Watsonia meriana var. bulbillifera) is a native plant of southern Africa that is an erect clumping perennial herb growing to 2.5 m, with tough sword-shaped leaves and orange trumpet-shaped flowers on erect stems.
• A garden escape, it has become a major environmental weed of disturbed bushland and roadsides, particularly near water. It is a particular problem in small areas of remnant vegetation.
• Bulbil Watsonia produces bulbils (small deciduous bulbs formed on the flowering stems after flowering in place of fruit and is a means of vegetative propagation).
• The production of very large numbers of stem bulbils has enabled it to become a very successful weed.
• Control involves the physical removal of corms and cormels (small corm a means of vegetative reproduction) from the soil, and the prevention of dispersal of the bulbils  by removing the flowering stems and the use of chemicals.
• Correct timing is essential for effective chemical control. Herbicide must be applied on corm exhaustion just as flower spike emerges.
• Plants resprout and appear to flower prolifically following fire.

What Does It Look Like?

What is it?

Bulbil Watsonia (Watsonia meriana var. bulbillifera) is an erect, clumping perennial herb growing to 2.5 m high, with leaves and flowers that dry off in late summer. The annually renewed underground corm is covered with a fibrous tunic. The leaves are sword-shaped, tough and fibrous, to about 100 cm long and 5 cm wide.

The flowers are trumpet-shaped but curved, usually dull orange but can be red or pink, 5–8 cm long. The tube is approximately twice as long as the 6 lobes. Flowers appear in spring and early summer.

Fruit and seeds are generally not produced in Australia. Instead Bulbil Watsonia produces clusters of egg-shaped bulbils on the flowering stem in place of fruits .  Bulbils a small deciduous bulbs formed on the flowering stem after flowering and is a means of vegetative propagation. THe bulbils appear at each node of the flower stalk, replacing the lower flowers. These enable the plant to spread easily along rivers, wetlands and roadside drains.  (Hussey et al. 1997; Parsons & Cuthbertson 2001; Thorp & Wilson 1998 -; Western Australian Herbarium 1998 -). Bulbil Watsonia the most invasive of the Watsonia species in Australia.

For further information and assistance with identification of Bulbil Watsonia contact the herbarium in your state or territory.

Flower colour

Red, Orange, Pink

Growth form (weed type/habit)

Herb

Where it currently grows? Preferred habitat

Bulbil Watsonia (Watsonia meriana var. bulbillifera) is adapted to a wide range of soil types and conditions. Although plants generally grow in winter-wet areas, along riverbanks, creeklines and roadside drains, in sandy clay and sandy loam, Bulbil Watsonia can also establish under drier conditions on sands (Muyt 2001; Western Australian Herbarium 1998 -).

Are there similar species?

Bulbil Watsonia is often confused with other Watsonia species and varieties (notably the closely related Watsonia meriana var. meriana) but only Bulbil Watsonia produces bulbils on the stem. It is also similar to African Cornflag (Chasmanthe floribunda) and Montbretia, (Crocosmia x crocosmiiflora). 

Monbretia has leaves that are only 1 to 2 cm wide and flower stems that are bent alternately in different directions whereas Bulbil Watsonia has leaves up to 5 cm wide and erect flower stems. 

African Cornflag (Chasmanthe floribunda) has a straight flower stem but a flower with an upper lobe that is much longer than the lower petals whereas Bulbil Watsonia has trumpet-shaped flowers with 6 equal lobes (Goldblatt 1999; Faithfull et al 2007).

Why Is It A Weed?

What are its impacts?

Native ecosystems: Bulbil Watsonia is a major environmental weed invading woodlands, heathlands, seasonal wetlands and riparian vegetation. In south-west Australia Bulbil Watsonia is a major threat to remnant vegetation along the Darling Scarp and the threatened plant communities of seasonally inundated clay based wetlands. The production of very large numbers of stem bulbils has enabled it to become a very successful weed, forming dense stands that exclude other vegetation (Muyt 2001; Parsons & Cuthbertson 2001; Faithfull et al. 2007).

Agriculture: The plant is suspected of being poisonous to livestock, but animals do not graze large plants and are apparently unaffected by consumption of young shoots. Bulbil Watsonia impoverishes soil and crowds out desirable pasture plants. It can cause serious loss of production but rarely persists in well-managed paddocks and cultivated areas and is of little importance as an agricultural weed. It can damage and impede the use of farm implements and the dead top-growth can create fire hazards (Parsons & Cuthbertson 2001; Faithfull et al. 2007)

How does it spread?

Bulbil Watsonia (Watsonia meriana var. bulbillifera) spreads by corms, bulbils and occasionally seed, moved by earth moving equipment, farm implements, vehicles, stock and water. Most new infestations probably originate from dumped garden refuse or by spread of bulbils in soil and on mowers and slashing equipment (Faithfull et al. 2007). Can be dispersed in hay, silage and grain.

What is its history in Australia?

Bulbil Watsonia (Watsonia meriana var. bulbillifera) was probably introduced to Australia as a garden ornamental. It appears in a list of plants growing in an Adelaide garden in 1842, at Camden Park in New South Wales in 1843 and the Melbourne Botanic Gardens in 1859 (Parsons & Cuthbertson 2001).

How To Manage It?

Best practice management

Where Bulbil Watsonia invades native plant communities it often co-occurs with a diverse range of native flora and so control options need to be relatively selective.

Chemical control: One method of selective control for Bulbil Watsonia invading bushland is the wiping of individual leaves with herbicide (Brown and Brook 2002). Although selective and reasonably effective it also is time consuming and sometimes impractical. Selected herbicides can be effective against Bulbil Watsonia without having an impact on co-occurring native species but timing is crucial. Herbicide application should take place when flowering stems are elongating and the parent corm is exhausted (see Moore & Fletcher 1994; Brown 2006). 

Please see the Australian Pesticides and Veterinary Medicines Authority for chemical information http://www.apvma.gov.au 

Non-chemical control: Manual control: Plants may be hand pulled to remove the corm in winter and spring when the ground is soft and wet. Plants that cannot be destroyed should have their stems removed before bulbils are dispersed. Hand removal however, is often impractical and the resulting soil disturbance can facilitate invasion of other weeds. Heavy infestations on agricultural land can be rotary hoed or ploughed deeply in late autumn and the corms raked from the surface and removed or burnt. The spread of Bulbil Watsonia can be controlled by grazing as livestock eat the young growth. Pigs eat the bulbils, and can be used in an eradication program (Parsons & Cuthbertson 2001; Faithfull et al. 2007). Slashing at 100 mm or closer to the ground when stems emerge and well before flowering can reduce stem and bulbil formation and weaken the corm (Herbiguide 2021).

Does it have a biological control agent?

NO

When does it grow? (lifecycle/growth calendar)

Corms and bulbils germinate in late autumn and develop a number of stiff, erect, strap-like leaves during winter. Stems emerge in spring and flowering commences by late October. Plants developing from corms or bulbils do not flower in the first year but may flower in either the second or third year. All aerial growth dies in summer but dead plants often remain standing for several months. Plants resprout and flower prolifically the autumn following summer fire. The mass flowering results in prolific bulbil production (Goldblatt 1999; Muyt 2001; Parsons & Cuthbertson 2001).

Where Is It Found?

Which states and territories is it found?

NSW, QLD, SA, TAS, VIC, WA

What areas within states and territories is it found?

Bulbil Watsonia is widely naturalised in moist-temperate regions of southern and eastern Australia (i.e. in south-eastern Queensland, the coastal and sub-coastal districts of eastern New South Wales, southern and central Victoria, Tasmania, south-eastern South Australia and the coastal and sub-coastal districts of south-western and southern Western Australia). It has also been recorded once in tropical northern Queensland (Parsons & Cuthbertson 2001; Weeds of Australia 2016).

Where does it originate?

Bulbil Watsonia (Watsonia meriana var. bulbillifera) is native to South Africa (Hussey et al. 1997).

National And State Weed Listings

Is it a Weed of National Significance (WONS)?

NO

Where is it a declared weed?

SA, VIC

Government weed strategies and lists – Weeds Australia

Is it on the National Alert List for Environmental Weeds?

NO

Government weed strategies and lists – Weeds Australia

Is it on the Agricultural Sleeper List?

NO

Government weed strategies and lists – Weeds Australia

Names And Taxonomy

Main scientific name

Watsonia meriana var. bulbillifera

Other scientific names (synonyms)?

• Watsonia bulbillifera J.W.Mathews & L.Bolus
• Watsonia meriana 'Bulbillifera'
• Watsonia angusta Ker Gawl. (misapplied by Beadle, N.C.W., Evans, O.D. & Carolin, R.C. 1972, Flora of the Sydney Region Edn 2. 544.)

Does it have other known common name(s)?

Bugle Lily, Merian's BugleLil, Watsonia, Wild Watsonia