Yellow soldier (Lachenalia reflexa)
Yellow soldier is a bulb. It produces a large number of viable seeds that germinate each year, leading to rapid expansion of populations.
Profile
How does this weed affect you?
Yellow soldier has since become a problem weed and is spreading through tuart (Eucalyptus gomphocephala) and banksia woodlands on sandy calcareous soils. It could become a significant environmental problem because it replaces native herbs and annuals in both disturbed and relatively intact bushland. Yellow soldier produces a large number of viable seeds that germinate each year, leading to rapid expansion of populations that are difficult to control.
What does it look like?
Yellow soldier belongs to a group of South African plants, many of which are grown as garden ornamentals. Three other species of Lachenalia are weeds of Western Australia.
Yellow soldier has two strap-shaped leaves, 60–350 mm long and 15–25 mm wide, which grow upwards from the base. The leaves are slightly V-shaped in cross-section. The bright yellow flowers are 25 mm long and more or less tubular in shape but swollen in the middle. They grow on short stalks just 45–100 mm above the ground.
Yellow soldier stores food material for the next growing season in bulbs, which are short underground stems.
Large healthy plants can produce up to ten yellow upright flowers. Plants flower particularly well following fire and set prolific amounts of seed.
The smooth, shiny black seeds are about 2 mm long. The seed does not appear to remain viable in the soil for more than two or three years.
Where is it found?
In its native range the genus Lachenalia extends mainly throughout western and southwestern Cape Province in South Africa. It occurs as a serious weed at a number of conservation reserves around Perth, Western Australia. It invades banksia/ tuart woodlands and limestone scrub and heath around the Swan estuary, banksia/jarrah woodland to the south and west of Perth, and tuart woodland up to 40 km north of Perth.
How does it spread?
With only a single annually renewed bulb, yellow soldier spreads mainly by seed. There are usually between one and ten flowers per plant and each flower produces a capsule that contains 40–60 seeds, potentially giving rise to infestations of more than 400 bulbs per square metre. Experience suggests that seed is not easily spread over long distances. Water movement and human activity are the main causes of seed spread. Yellow soldier seeds often germinate in response to fire, taking advantage of any bare ground and the reduction in competition from native species. Plants have also been observed to produce a prolific number of bulbils (small bulbs) around the base of stems left lying on the soil surface, but this does not appear to be a common method of reproduction or dispersal.
What type of environment does it grow in?
In its native range the genus Lachenalia occurs in areas with winter rainfall, undergoing long dormant periods over the dry summers. In Australia it has invaded woodlands and limestone scrub areas.
Acknowledgements
CRC for Australian Weed Management: Kate Brown (Environmental Weeds Action Network), Greg Keighery (CALM WA), Sandy Lloyd (Agriculture WA/Weeds CRC) and John Thorp (National Weeds Management Facilitator).
Control
There are a number of difficulties associated with controlling bulbous weeds such as yellow soldier growing in native vegetation. Because there are relatively few yellow soldier infestations, and it can potentially be eradicated before it becomes established, any new outbreaks should be reported immediately to your local council weed officer. Do not try to control yellow soldier without their expert assistance. Control effort that is poorly performed or not followed up can actually help spread the weed and worsen the problem.
Removal by hand
In sandy soils bulbs can be removed by hand in late August – early September by cutting the roots with a knife and pulling them out with the bulb. However, hand removal is difficult and time consuming, and can cause major soil disturbance which may encourage other weeds. It is often impractical on a larger scale, especially given the high density at which these bulbous weeds often occur.
Fire is not recommended for control
Yellow soldier appears to be tolerant of fire and regenerates soon after bushfire. Plants appear to flower particularly well following fire, setting prolific amounts of seed. In addition, fire reduces competition from native vegetation and creates bare areas where seed can germinate. However, fire can create opportunities for land managers to prevent further spread and establishment. After fire, yellow soldier’s flowers are clearly visible, and the reduced cover of native vegetation makes the resprouting flowering bulbs easy targets for herbicide control.
Follow-up work will be required
Once the initial infestation is controlled, follow-up monitoring and control will be required to ensure that reinfestation does not occur.
Herbicide options
WARNING - ALWAYS READ THE LABEL
Users of agricultural or veterinary chemical products must always read the label and any permit, before using the product, and strictly comply with the directions on the label and the conditions of any permit. Users are not absolved from compliance with the directions on the label or the conditions of the permit by reason of any statement made or not made in this information. To view permits or product labels go to the Australian Pesticides and Veterinary Medicines Authority website www.apvma.gov.au
Users of agricultural or veterinary chemical products must always read the label and any permit, before using the product, and strictly comply with the directions on the label and the conditions of any permit. Users are not absolved from compliance with the directions on the label or the conditions of the permit by reason of any statement made or not made in this information. To view permits or product labels go to the Australian Pesticides and Veterinary Medicines Authority website www.apvma.gov.au
See Using herbicides for more information.
PERMIT 9907 Expires 31/03/2025
Fluroxypyr 200 g/L
(Various products)
Rate: 500 mL to 1 L per 100 L water
Comments: Spot spray
Withholding period: Do not graze failed crops and treated pastures or cut for stock feed for 7 days after application. See label for further information.
Herbicide group: 4 (previously group I), Disruptors of plant cell growth (Auxin mimics)
Resistance risk: Moderate
PERMIT 9907 Expires 31/03/2025
Fluroxypyr 333 g/L
(Starane™ Advanced)
Rate: 300 to 600 mL per 100 L water
Comments: Spot spray
Withholding period: Do not graze failed crops and treated pastures or cut for stock food for 7 days after application. See label for more information.
Herbicide group: 4 (previously group I), Disruptors of plant cell growth (Auxin mimics)
Resistance risk: Moderate
PERMIT 9907 Expires 31/03/2025
Glyphosate 360 g/L
(Various products)
Rate: One part product to 50 parts water
Comments: Spot spray
Withholding period: Nil.
Herbicide group: 9 (previously group M), Inhibition of 5-enolpyruvyl shikimate-3 phosphate synthase (EPSP inhibition)
Resistance risk: Moderate
PERMIT 9907 Expires 31/03/2025
Glyphosate 360 g/L
(Various products)
Rate: One part product to 9 parts water
Comments: Splatter gun
Withholding period: Nil.
Herbicide group: 9 (previously group M), Inhibition of 5-enolpyruvyl shikimate-3 phosphate synthase (EPSP inhibition)
Resistance risk: Moderate
PERMIT 9907 Expires 31/03/2025
Glyphosate 360 g/L
(Various products)
Rate: One part product to 20 parts water
Comments: Wipe onto leaves
Withholding period: Nil.
Herbicide group: 9 (previously group M), Inhibition of 5-enolpyruvyl shikimate-3 phosphate synthase (EPSP inhibition)
Resistance risk: Moderate
PERMIT 9907 Expires 31/03/2025
Metsulfuron-methyl 600 g/kg
(Various products)
Rate: 10 - 20 g per 100 L water plus surfactant
Comments: Spot spray
Withholding period: Nil (recommended not to graze for 7 days before treatment and for 7 days after treatment to allow adequate chemical uptake in target weeds).
Herbicide group: 2 (previously group B), Inhibition of acetolactate and/or acetohydroxyacid synthase (ALS, AHAS inhibitors)
Resistance risk: High
PERMIT 9907 Expires 31/03/2025
Metsulfuron-methyl 600 g/kg
(Various products)
Rate: 10 g per 1 L of water plus surfactant
Comments: Wipe onto leaves
Withholding period: Nil (recommended not to graze for 7 days before treatment and for 7 days after treatment to allow adequate chemical uptake in target weeds).
Herbicide group: 2 (previously group B), Inhibition of acetolactate and/or acetohydroxyacid synthase (ALS, AHAS inhibitors)
Resistance risk: High
Biosecurity duty
The content provided here is for information purposes only and is taken from the Biosecurity Act 2015 and its subordinate legislation, and the Regional Strategic Weed Management Plans (published by each Local Land Services region in NSW). It describes the state and regional priorities for weeds in New South Wales, Australia.
| Area | Duty |
|---|---|
| All of NSW | General Biosecurity Duty All pest plants are regulated with a general biosecurity duty to prevent, eliminate or minimise any biosecurity risk they may pose. Any person who deals with any plant, who knows (or ought to know) of any biosecurity risk, has a duty to ensure the risk is prevented, eliminated or minimised, so far as is reasonably practicable. |
For technical advice and assistance with identification please contact your local council weeds officer.
Reviewed 2020
