Yellow Soldier (Lachenalia Reflexa), Weed Management Guide

This document was originally published on the website of the CRC for Australian Weed Management, which was wound up in 2008. To preserve the technical information it contains, the department is republishing this document. Due to limitations in the CRC’s production process, however, its content may not be accessible for all users. Please contact the department’s Weed Management Unit if you require more assistance. al er t l is t for envi ronment a l weeds Yellow soldier – Lachenalia reflexa ● Current Yellow soldier (Lachenalia reflexa) The problem Yellow soldier is on the Alert List for Environmental Weeds, a list of 28 non native plants that threaten biodiversity soldier Yellow and cause other environmental damage. Although only in the early stages of establishment, these weeds have the potential to seriously degrade Australia’s ecosystems. – Lachenalia reflexa Yellow soldier was first recorded as naturalised south of Perth, Western Australia, in 1957, probably after escap ing from a garden planting. It has since become a problem weed and is spread ing through tuart (Eucalyptus gomphocephala) and banksia woodlands Yellow soldier has two strap-shaped leaves which are slightly V-shaped in cross-section. Photo: Kate Brown on sandy calcareous soils. It is most common in the southwest of the state, a region renowned for its high biodiversity Yellow soldier has two strap-shaped Key points leaves, 60–350 mm long and 15–25 mm and unique aesthetic qualities. wide, which grow upwards from the • Prevention and early intervention are the It could become a significant environ- base. The leaves are slightly V-shaped in most cost-effective forms of weed control. Once mental problem because it replaces cross-section. The bright yellow flowers established, yellow soldier is difficult to control native herbs and annuals in both disturb- are 25 mm long and more or less tubular so it is important to keep uninfested areas ed and relatively intact bushland. Apart in shape but swollen in the middle. They weed free. from causing a loss of plant biodiversity, grow on short stalks just 45–100 mm • Yellow soldier produces a large number of viable which destroys habitat and resources for above the ground. seeds that germinate each year, leading to rapid expansion of populations. native animals, infestations of yellow Yellow soldier stores food material for • A number of species of Lachenalia are present soldier can reduce the recreational the next growing season in bulbs, which in Australia but yellow soldier is considered the enjoyment of bushland by people. are short underground stems. Large most widespread and invasive. healthy plants can produce up to ten • Contact your state or territory weed manage- yellow upright flowers. Plants flower The weed ment agency or local council if you find yellow particularly well following fire and set soldier. Do not attempt control on your own. Yellow soldier belongs to a group of prolific amounts of seed. The smooth, South African plants, many of which are shiny black seeds are about 2 mm grown as garden ornamentals. Three long. The seed does not appear to other species of Lachenalia are weeds remain viable in the soil for more than of Western Australia (see Box, p.3). two or three years. 2 Growth calendar Yellow soldier is considered the most widespread and invasive of the natural ised Lachenalia species in Australia. It Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec occurs as a serious weed at a number Flowering of conservation reserves around Perth, Die back Western Australia. It invades banksia/ Germination tuart woodlands and limestone scrub General growth pattern and heath around the Swan estuary, Yellow soldier seeds germinate during spring and flower during the following winter banksia/jarrah woodland to the south and early spring. The above ground foliage dies off during summer. and west of Perth, and tuart woodland up to 40 km north of Perth. How it spreads Plants have also been observed to Why we need to be ‘alert’ produce a prolific number of bulbils to yellow soldier With only a single annually renewed (small bulbs) around the base of stems bulb, yellow soldier spreads mainly by left lying on the soil surface, but this Yellow soldier could spread over most of seed. There are usually between one and does not appear to be a common the Swan coastal plain in southwestern ten flowers per plant and each flower method of reproduction or dispersal. Western Australia. Based on climatic produces a capsule that contains suitability, it could potentially spread to 40–60 seeds, potentially giving rise to Where it grows areas with sandy soils in South Australia infestations of more than 400 bulbs per and Victoria. square metre. In its native range the genus Lachenalia The infestation in the Shenton extends mainly throughout western and Experience in the Shenton bushland in bushland has shown that yellow soldier southwestern Cape Province in South Western Australia (see case study p. 5), does not need disturbance to establish, Africa, where it occurs in areas with where populations are quite discrete, as many of the infestations occur in – Lachenalia reflexa winter rainfall, undergoing long dormant suggests that seed is not easily spread relatively intact bushland. This indicates periods over the dry summers. over long distances. Water movement that yellow soldier could become a major environmental weed and potentially have and human activity are the main causes Yellow soldier is most common in the of seed spread. southwest of the state of Western severe impacts in conservation areas, Australia, a region renowned for its displacing more desirable native species Yellow soldier seeds often germinate Yellow soldier Yellow high biodiversity and unique and altering the ecological balance of in response to fire, taking advantage aesthetic qualities these areas. of any bare ground and the reduction in competition from native species. There are a number of difficulties associated with controlling bulbous weeds such as yellow soldier growing in native vegetation. See the case study (p. 5) for more information. What to do about it Prevention is better than the cure As with all weed management, prevention is better and more cost- effective than control. The annual cost of weeds to agriculture in Australia, in terms of decreased productivity and management costs, is conservatively Yellow soldier produces a prolific amount of smooth, shiny, black seed. estimated at $4 billion. Environmental Photo: Kate Brown impacts are also significant and lead to We ed Management Guide • Yellow soldier – Lachenalia reflexa 3 Other weedy naturalised species of Lachenalia In recent years a number of Lachenalia species have become naturalised in southern Australia. Lachenalia aloides has been recorded as a weed in lowland grassland and grassy woodland in Victoria, while L. aloides and L. bulbifera have been recorded as garden escapees in South Australia. In southwestern Western Australia four species, L. aloides var. aurea, L. bulbifera, L. mutabilis and L. reflexa, have been recorded as weeds. Although these species are still very localised, they are spreading through woodlands in this region. 200 mm The various species of Lachenalia are similar looking, although there is some variation in plant size and flower colour. L. aloides grows 50–310 mm high and has flowers in a range of colours including orange, red, yellow and greenish blue. L. bulbifera grows 80–300 mm high and has orange to red flowers, with darker red or brown markings and green tips. L. mutabilis is the largest of the four species, growing 100–450 mm high, with pale blue and white flowers with yellow tips, and only one leaf. Yellow soldier (L. reflexa) is the smallest species (30–190 mm high) and has pure yellow flowers. L. aloides has flowers in a range of colours including orange, red, yellow and greenish blue. Photo: Penny Hussey a loss of biodiversity. To limit escalation In the past various Lachenalia species of these impacts, it is vital to prevent have been offered for sale in nurseries Early detection and eradication are also further introduction of new weed around Australia, including in Western important to prevent infestations of species, such as yellow soldier, into Australia, South Australia and Victoria. yellow soldier. Small infestations can uninfested natural ecosystems. Notify the vendor or state or territory be easily eradicated if they are detected weed control contacts if you find Yellow soldier flowers particularly early but an ongoing commitment is Lachenalia for sale. well following fire and sets prolific needed to ensure new infestations do amounts of seed not establish. The Alert List for Environmental Weeds The Federal Government’s Alert List for Environmental Weeds was declared in 2001. It consists of 28 weed species that currently have limited distributions but potentially could cause significant damage. The following weed species are therefore targeted for eradication: Scientific name Common name Scientific name Common name Acacia catechu var. sundra cutch tree Koelreuteria elegans ssp. formosana Chinese rain tree Acacia karroo Karroo thorn Lachenalia reflexa yellow soldier Asystasia gangetica ssp. micrantha Chinese violet Lagarosiphon major lagarosiphon Barleria prionitis barleria Nassella charruana lobed needle grass Bassia scoparia kochia Nassella hyalina cane needle grass Calluna vulgaris heather Pelargonium alchemilloides garden geranium Chromolaena odorata Siam weed Pereskia aculeata leaf cactus Cynoglossum creticum blue hound’s tongue

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