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. Scotch broom – Cytisus scoparius and other introduced brooms ) ) . They Cytisus scoparius) Genista monspessulana ( ( Scotch broom Scotch broom Cape broom Recorded distribution: Recorded ● ● southern Australia, some are widespread and southern widespread Australia, some are others localised at this stage. soil nitrogen. plants and increase They often form a if damaged. resprout long-lived seedbank. for Scotch broom. the weed. conditions that initially promote native vegetation, it is necessary restore To to take this into account. native plants. replaces broom seed and before brooms. native plants resemble mainly in gardens. commonly grown, are White weeping broom (Retama raetam) White weeping broom (Cytisus and white Spanish broom Australian Alert on the multiflorus) are have a List because they currently limited distribution but have potential to biodiversity to become threats are the subject of their own weed the subject are management guides under the Alert are List series. These and other brooms (or Tagasaste still cultivated in gardens. lucerne)tree (Chamaecytisus palmensis is commonly planted for fodder in WA is commonly planted for fodder in WA but is also a weed of native vegetation. Key points points Key • species invade native vegetation in Broom • native outcompete rapidly, They can grow • seed and plants from reproduce Brooms • agents have been released Biological control • stands generally creates Removing broom • they plants before to remove It is most effective • weed identification is essential. Some Correct • species, cultivars and hybrids Many broom ) ehabilitation owth rate and scoparius oom-infested sites, and for reducing oom-infested sites, and for reducing ough their rapid gr Scotch broom and Montpellier broom and Montpellier broom Scotch broom by disturbance but are promoted are into intact native vegetation. spreading They outcompete native understorey thr of br has also commenced Research spread. into organisms with potential for Montpellier broom. controlling high seed output, increase soil fertility high seed output, increase and dominate the soil seedbank. It is native to restore particularly difficult vegetation long invaded by brooms. Several insects that feed selectively plants or seeds have on Scotch broom to Australia, but their been introduced impacts have generally been limited. may become a useful Biological control it is integrated with other tool, where for long-term r measures Cytisus scoparius) is invading native woodland at high elevations in the Australian

Brooms are shrubs in the pea family are Brooms widely cultivated (Fabaceae) that are for ornamental or other purposes. A number of species, mostly native to Africa have been introduced or Europe to Australia and become weeds. (Cytisus Scotch (or English) broom scoparius) and Montpellier (or Cape) ) are (Genista monspessulana broom weeds that have formed widespread major infestations in southern Australia. in Australia Most studies of broom have focused on these and they are Other here. the main species profiled have a more species that currently in less covered limited distribution are detail but may be of equal or greater in certain situations. threat The problem The problem Managing weeds for biodiversity weeds for biodiversity Managing Scotch broom ( Scotch broom (including stock), vehicles, animals carried by people, native and introduced Alps. Its seeds are of isolated patches is a management priority. Detection and removal machinery and water. Photo: Parks Victoria

and other introduced brooms brooms and other introduced (Cytisus broom Scotch 2

in their environmental tolerances and Where they grow other aspects of their biology, in general they are able to resprout, are tolerant Scotch broom is native in Europe and of dry summers, have been deliberately Macronesia and the other introduced planted and have high seed production, brooms are native in the general region including some dormant seed. All of Europe, the Mediterranean, Middle brooms have root nodules that fix East and Macronesia. Various brooms nitrogen, assisting their growth in have become naturalised elsewhere relatively infertile soils and modifying including southern Africa, North and the soil environment. These features South America, New Zealand and parts are major considerations in planning of Asia. their management. Features of the Species such as Montpellier broom main broom species naturalised in have become weeds across southern Australia are summarised in the table Australia, others have a more limited on pages 4 and 5. distribution and some are currently quite localised. Most brooms generally How they spread grow in regions with rainfall in winter and a Mediterranean or temperate Several colour forms or hybrids of Scotch Brooms grow from seed. In Scotch broom (Cytisus scoparius) occur in the wild. climate, with some extending into and Montpellier brooms most seed set Photo: Matthew Baker, Tasmanian Herbarium southeastern Qld. Brooms can grow in results from cross pollination by honey relatively infertile sand or loam. Scotch bees or other large insects. A small broom is spreading rapidly in subalpine The weeds proportion of flowers set seed but woodlands with a mainly herbaceous mature stands can produce abundant Scotch broom is an erect shrub to 3 m understorey. It invades a range of seed in favourable seasons due to tall with green stems, five-angled young shrubby or grassy native vegetation many-seeded pods, large plants, dense branches and leaves that are shed in types; grassland, woodland, sclerophyll populations and prolific flowering. times of stress. The large, showy pea- forest, and riparian vegetation that is Spanish broom has a similar breeding flowers are borne singly on stalks along not densely shaded, with an average system. White weeping broom also the branches. They are usually bright annual rainfall of 600 mm or more. produces abundant seed with high yellow but in some forms the petals Montpellier broom occurs in a similar viability and a high percentage are may be splashed with red, or pink in range of habitats, has been recorded initially dormant. colour. Pods are oblong, hairy along in swamps but extends into drier areas the opening and black when mature. Scotch broom and some other species with an annual rainfall of 500 mm or Foliage can be browsed by livestock. have pods that burst open in hot more. Flax-leaf broom has a similar

– Cytisus scoparius and other introduced brooms Research has indicated that Scotch weather when mature, ejecting seeds range to Montpellier broom but is less broom grows rapidly when moisture is up to several metres. Seed is also common. Spiny broom, white Spanish available, outgrowing common native carried by run-off or floods and can roll broom and Spanish broom generally shrubs. Dense broom stands produce downhill or be buried by ants. It can be occur in lowland grasslands, relatively high, homogeneous levels of carried inadvertently in soil by humans, woodlands and dry sclerophyll forest. leaf litter in comparison with diverse

Scotch broom Scotch broom animals or vehicles and outliers may Tagasaste requires acid to neutral soil native vegetation, and this may be found in native vegetation at some and an average annual rainfall of disadvantage native species. In eastern distance from parent populations. 350 mm or more, and grows in a NSW, dense Scotch broom harbours Brooms planted in gardens can spread wide range of vegetation types. White feral pigs that dig the soil, promoting into bushland. Various species have also weeping broom originated from desert broom regeneration. been planted as hedge, soil binding, regions and is tolerant of low rainfall, medicinal or fodder plants. Disturbance Brooms generally have numerous occurring in SA and WA where the assists broom invasion by removing straight, flexible young branches that annual rainfall averages 300–500 mm. competing vegetation and stimulating give them their common name. While It can grow in sand and in alkaline broom seed germination. the different introduced brooms vary soils and invades coastal vegetation and mallee.

Weed Management Guide • Scotch broom – Cytisus scoparius and other introduced brooms 3

Similar native species

These native Australian shrubs with yellow pea-flowers could be mistaken for certain introduced brooms and may grow in similar habitats.

Golden spray or Australian native broom (Viminaria juncea) is a shrub 1–5 m tall. Its stems are not ridged, mature leaves are reduced to wiry petioles (stalks) 3–25 cm long. Flowers are yellow to orange, may have reddish markings, in a spray, up to 20 cm or more long. Pods are small with a wrinkled surface, containing 1 seed. Often grows in swampy areas. It occurs in NSW, Qld, SA, Tas., WA, Vic. (Resembles the weeds Scotch and Spanish brooms). Photo: Jackie Miles and Max Campbell

Golden tip or clover bush (Goodia lotifolia) and western golden tip (G. medicaginea) are shrubs to 4 m or 1.5 m tall respectively. Young branchlets are not ridged. Leaves are clover-like with a long stalk and 3 egg-shaped leaflets. Flowers are borne in groups at the end of branches, stalked, yellow to orange with darker markings. Pods are irregularly oval to oblong, stalked with a narrow base, not hairy. One or both species occur in NSW, Qld, SA, Tas., Vic., WA. (Resembles the weed Montpellier broom). Photo: Jackie Miles and Max Campbell

Giant wedge-pea (Gompholobium latifolium) is a shrub to 3 m tall, with narrow leaflets in threes Scotch broom on a short stalk. The yellow flowers are in groups of 1–3, borne at tips and along branches. Pods are ovoid to obloid, to 18 mm long, not hairy, containing numerous seeds. It occurs in NSW, Qld, Vic. (Its narrow leaves resemble those of flax-leaf broom. Other species of Gompholobium could also be mistaken for broom species). Photo: Jackie Miles and Max Campbell – Cytisus scoparius and other introduced brooms Large-leaf bush-pea (Pultenaea daphnoides) is a shrub, 1–3 m tall, stems not ridged, leaves not divided into leaflets, darker above than below, firm, variable but often wedge-shaped. Flowers are without stalks, in clusters of 6–15 at branch tips, yellow and red. Pods are flattened, 5–7 mm long, pubescent. It occurs in NSW, Qld, SA, Tas., Vic. (It commonly grows amongst the weedy shrubs of Montpellier and Scotch brooms). Photo: Jackie Miles and Max Campbell

Dogwood (Jacksonia scoparia) is a shrub, up to 3 m tall, with silvery-grey stems and thick fissured bark and may be weeping in habit. Most leaves are usually reduced to scales. Flowers are yellow, in groups at or near the ends of branches. Pods are 6–12 mm long. It occurs in NSW, Qld. (Resembles the weeds Scotch and Spanish brooms). Photo: Jackie Miles and Max Campbell

Potential distribution Growth cycle Montpellier broom flowers when 2 years old and lives for 8–10 years. Climate modelling has been undertaken Scotch broom plants first flower at It produces new growth in winter to at the national level for Scotch and 3–5 years old and may live for up to spring and flowers in late winter to Montpellier brooms. It indicates that 27 years. Leaves are often deciduous, spring. Pods ripen in summer and seeds there is potential for further spread of falling in dry or cold seasons, but the mainly germinate in the autumn. In its native range, recruitment is episodic both these species in southern Australia green stems enable continued and native populations are eventually and for Scotch broom into WA. Genetic photosynthesis. Flowering occurs mainly replaced by longer-lived species if not studies of this species indicate that a in spring and seeds ripen and shed in disturbed. However, Montpellier broom diversity of genetic forms was introduced summer. They can germinate in the populations in Australia reproduce to Australia from its extensive native warmer months. A proportion of seed without disturbance and are persistent. and introduced range and that further may become dormant and survive in Many other brooms also have seed diversity is arising here. Modelling the seedbank for 20 or more years. In that germinates soon after shedding undertaken for most of the introduced Australia, recruitment of seedlings can and some hard seed that is long-lived brooms in Vic. indicates that they have occur under a mature Scotch broom in the soil seedbank. Germination of potential to become more widespread. canopy if there is adequate light, this seed is promoted by soil disturbance, contributing to stand persistence. an increase in light levels, or fire.

Weed Management Guide • Scotch broom – Cytisus scoparius and other introduced brooms Scotch broom – Cytisus scoparius and other introduced brooms Naturalised broom species in Aust Weed Management Guide • Scotch broom– Species Habit Flowers and season Leaves Seed pods Legislation and notes Distribution Scotch or English broom Shrub 1–4 m tall; Yellow but some Simple or 3 leaflets on a Narrowly oblong, Declared in ACT, NSW, ACT, NSW, SA, Tas., Vic. (Cytisus scoparius) young branches naturalised hybrids have stalk; sparse; deciduous 25–70 mm long, hairy SA, Tas., Vic. Photo: Matthew Baker, 5-angled red and yellow flowers, when plants are stressed along the opening; Widespread in cool Tasmanian Herbarium 15–25 mm long; single up to 22 seeds Quarantine weed wet areas or in pairs in WA Origin: Macronesia, Mainly late winter AQIS not permitted Europe to summer Montpellier or Shrub 1–3 m tall; Yellow, 8–13 mm long; 3 egg-shaped leaflets Narrowly oblong, Declared in ACT, NSW, ACT, NSW, Qld, SA, Cape broom stems ribbed usually in groups of on a short stalk 15–30 mm long, densely SA, Tas., Vic. Tas., Vic. WA (Genista monspessulana) 3–7 on short branches hairy; 5–8 seeds Photo: Jackie Miles and AQIS not permitted Widespread in Max Campbell Late winter and spring, southeastern Australia sometimes late summer and autumn Origin: Mediterranean, Georgia Flax-leaf broom Shrub 1–3 m tall; Yellow, 10–15 mm long; 3 narrow leaflets, Narrowly oblong, Declared in ACT, NSW, SA, Tas., Vic., WA

(Genista linifolia) stems ribbed in groups of 3–16 10–25 mm long, 13–30 mm long, densely NSW, Vic. ralia: main species and features Photo: Jackie Miles 0.5–4.5 mm wide; hairy; 2–6 seeds Scattered locations

and Max Campbell Mainly in spring margins rolled under AQIS not permitted 4 Cytisus Origin: Canary Islands, W. Mediterranean

scoparius Spanish or weavers Shrub to 3 m Yellow, 20–30 mm long, Simple, 10–30 mm long, Slender, 60–80 mm Declared in ACT, NSW ACT, #NSW, Qld, SA, broom (rarely to 5 m) tall; scented; in sprays, 2–5 mm wide; sparse, long, approx. 6 mm Tas., #Vic. (Spartium junceum) stems not ribbed 5–20 flowered may shed when plants wide; becoming hairless; Photo: Matthew Baker, are stressed mostly with 10–15 seeds Localised, uncommon Tasmanian Herbarium Spring to early summer

and other introduced brooms Origin: Azores, Mediterranean, Caucasus Spiny broom Shrub to 3 m tall Yellow, 12–15 mm long; 3 leaflets, 5–10 mm Oblong, 25–45 mm Declared in Vic. Vic. (Calicotome spinosa) with rigid spines in clusters of 1–5 long, 2–5 mm wide; long; lower margin Photo: Andrew Steed to 7.5 cm long; on a stalk up to winged, almost hairless; Quarantine weed Localised, uncommon stems hairless 10 mm long 5–15 seeds Early summer in WA (Nov—Dec) Origin: Mediterranean AQIS not permitted 5

Weed identification

Introduced brooms naturalised in Australia have pea-flowers of various sizes and colours (mainly yellow or white). The stems are generally green and in some species leaves drop early so they are usually leafless. Leaves may ACT, NSW, SA, Tas., NSW, ACT, Middle East, Canary Islands Vic. Origin: Mediterranean, Vic., WA. Vic., WA. Widespread Origin: Canary Island Distribution be simple, comprise leaflets in threes, or both types may be present. The

) is hybrid brooms grown in gardens commonly have weedy species as one or both parents. Gorse (Ulex europaeus), a relative of brooms, is a Weed of Alert List species Localised, uncommon in California similar and is invasive for fodder Bridal broom Bridal broom ( R. monosperma Localised Legislation and notes hybrids including C. x dallimorei National Significance.

The main features of the broom species

naturalised in Australia are summarised Scotch broom in the table on the following page.

essed silky; mostly Other broom species not covered appr or opening late mostly 40–60 mm long, opening at maturity 8–12 mm wide; densely mainly with Commonly planted hairy, 4–10 seeds short point or beak; 1–2 seeds; either not Obovoid, 15 mm long, Alert List species SA, WA Seed pods with 3–7 seeds of horticultural Parent Origin: SW Europe in the table: Dallimore’s Spanish broom (Cytisus x – Cytisus scoparius and other introduced brooms dallimorei) = Cytisus scoparius cv. ‘andreanus’ x Cytisus multiflorus is a WA Quarantine Weed.

Madeira broom (Genista stenopetala) long, 4 mm wide on a 15–30 mm long, Simple, tiny, narrow, Simple, tiny, is naturalised but uncommon and localised in southeastern Australia. It is sometimes confused with G. x spachiana (naturalised in Vic.). It is a shrub to 6 m tall with terminal sprays of yellow flowers. long; 1–3 per leaf axil stalk, and simple leaves 4–7 mm wide, streak, approx. 10 mm approx. streak, Mainly winter and spring 15–20 mm long; in long on a stalk Winter and early spring Cream to white, Cream 3 leaflets 10–45 mm Linear—oblong, Not declared Flowers and season Leaves Spring Dyers broom (Genista tinctoria) was recorded in Victoria but is probably not naturalised in Australia.

What to do about it stems ribbed to 5 m tall; branches hairy of 3–7 or more groups Shrub to 3 m tall; White with a pink 3 leaflets to 12 mm Linear—oblong, in Tas. Declared hairy when young of 3–15 Shrub or tree Shrub or tree ‘weeping’ habit; pinkish base, in clusters hairy; deciduous 10 mm wide with a Shrub to 3 m tall, White, 8–10 mm long, Habit Strategies need to be developed at

) the regional level, to prevent brooms spreading and to reduce their impacts on biodiversity. In regions where one or more brooms are widespread, total eradication may not be a realistic goal. Photo: Yoshi Nomura Photo: Yoshi ( Cytisus multiflorus tagasaste ( Chamaecytisus palmensis ) Max Campbell Photo: Jackie Miles and White Spanish broom Photo: John Virtue, SA DWLBC Tree lucerne or Tree ( Retama raetam ) White weeping broom White weeping broom Species Sites of biodiversity significance need to be identified and accorded high priority for weed management. At the local or property scale a long-term management program targeting all brooms can reduce their harmful effects, # Where the state flora or census records a species as present but not truly naturalised. a species as present the state flora or census records # Where

Weed Management Guide • Scotch broom – Cytisus scoparius and other introduced brooms Scotch broom – Cytisus scoparius and other introduced brooms ar particularly local nativespeciesthat on alter known tospr some cultivatedformshavebeen not alwayslabelledconsistently and species ar br Raise communityawareness ofweedy species maylooksimilartobrooms. identification isessentialassomenative flowering, generallyinspring.Accurate plants are mosteasilydetectedwhen establishing intheregion. Isolated and prevent additionalweedspecies Keep uninfestedareas free ofbroom plants orclumpsfirstandfollowup. Remove seedlingsandtreat isolated as isolatedplantsorsparsepopulations. Identify locationswhere broom occurs Prevent brooms spreading: details are listedinthecontact table. assist intheseefforts, departmental control agents.Foropportunities to distribution andmonitoringofbiological sometimes beinvolvedintheraising, Community groups andschools can programs: Assist withbiologicalcontrol the ageofinfestation. and typeofnativevegetationalso removal isaffected bythecondition of asitetorecover followingbroom native vegetationtorecover. Thecapacity help containspread andencourage Strategic weeding innative vegetation Weed Management Guide • Scotch broom– e availableforgardens. ooms. Anumberofthenaturalised Native vegetation Weed from theleastweed-infestedbushtowards weed-dominatedareas native non-weedyplants, e stillavailableforsale,ar ead. Pr ovide information e • • • 2. Developthesiteactionplan • • 1. Investigatethesite weed managementplan. Develop andimplementalong-term the distributionofothermajorweeds. knowledge aboutthesite—including a planneedstobebasedonspecific on broom biologyandcontrol methods, the informationpresented inthisguide regrowth orotherweeds.Aswellas cover ratherthannewbroom seedlings, broom isreplaced bydesirableplant essential toensure thatafter treatment, A planned,strategicapproach is infestations: Reduce established sites forer fauna habitatvaluesandhigh-risk Values andrisks: rare flora. of highbiodiversityvalue,suchas br assess itscapacityforrecovery after Map nativevegetationcondition: on thesiteinformation. Identify goalsandprioritiesbased other factors. which r identify majorsour weed densitythr Map weedinfestations: plants thatneedpr including allbr Identify allplantspecies: oom isremoved andidentifysites e-invasion canoccur osion potentialand 6 Cytisus ooms andnative oughout thesite, identify native ces ofseedfr otecting. scoparius indicate Weeds . weeds om and other introduced brooms Thesizeofthear • Pr • Selectthemostsuitablecontrol • Includecontrol ofotherweedsso • to focusonthe removal ofweedsas programs there isoftenatendency r Include monitoringofnativeplant and adapttheplanaccordingly 4. Monitorandevaluateoutcomes Coordinate control programs with • Followupbr • Removebroom fr • 3. Implementtheactionplan Plantoweedstrategically: • Definepriorityareas forcontrol by • egeneration. Inweedmanagement befor and r to followupthoroughly. Seedlings stage shouldbemanageableenough seasons ofkeynativespecies. including avoidingthebr effectiveness ofcontr calendar tomaximisethe of weedmaterial. vegetation. Planappropriate disposal stage toavoiddamagenative method foreachweedgrowth broom hasbeenremoved. that theydonotestablishwhere ongoing spread. maximise effectiveness andreduce neighbouring landholdersto moving furtherintotheinfestation. in areas previously treated before conditions. the seed.Adapttolocalseasonal ensure thatactivitiesdonotspread areas. Minimisesoildisturbance and infested ar contr – workfrom isolatedbroom plants – pr – native vegetation,sitevaluesandrisks. overlaying mapsofweeddensity, epare aweedmanagement to downstr towards core infestations needs ofrar vegetation firstandconsiderthe otect thebetterqualitynative egrowth needtoberemoved e theyr ol plantsfr eas intothemore infested oom regrowth eachyear eplenish theseedbank. eam. e faunaandflora ea targetedateach om theleast om upstream ol activities eeding 7

native plants regenerate and the treatments to selectively remove broom broom seedbank declines. Methods regenerating among natives. that are effective on the major broom weeds are generally the starting point Physical weed removal for trials on the less common species. Hand pulling can be an effective Different methods may be appropriate method for removing small or isolated for sparse broom plants amongst broom plants within native vegetation. native vegetation, compared with If a stand has been established for only dense, established infestations. a few years, remove plants before seeding, but for older stands that Biological control already have a broom seedbank this Due to the major threat to native is less critical. Small to medium-sized vegetation from Scotch broom in south plants can be hand pulled when the eastern Australia, biological control soil is moist, but the resulting disturbance agents have been introduced for this of the soil and increased light will lead species. Several insects have become to germination of soil-stored seed in

White weeping broom (Retama raetam) established in Australia but have not mature infestations. Hand weeding Scotch broom seedlings rapidly develop deep taproots and yet had a major impact on its infestations or other treatment will be necessary survive dry conditions. Photo: D. Agnew, Northern and Yorke or its spread. More recently, research to continue the follow up work, while NRM Board has commenced into biological control protecting native plants. Avoid removing of Montpellier broom and potential plants carrying mature seed if possible, agents have been identified. As these otherwise safe disposal is required. a goal, but at the site level the ultimate – Cytisus scoparius and other introduced brooms goal is restoration of native vegetation, broom species are also major weeds in Weed material can be either bagged or productive pastures for grazing America and New Zealand, biological and removed, or heaped and carefully properties. control research has involved burnt on site, ensuring that no viable international collaboration. seed remains.

Control methods In accessible, broom-infested areas Fire such as non-native pastures, Brooms are difficult to manage in Burning is often seen as an effective mechanical equipment may be used to native vegetation because they form first stage in controlling weeds such mulch non-seeding broom plants with dense stands, have a high growth rate, as broom as hot fire removes the minimum soil disturbance. The layer of produce a large seedbank and generally above ground plants and destroys or broom mulch may suppress regrowth resprout from the base. Seed may stimulates germination of soil-stored and seedlings temporarily, assisting germinate in large numbers after seed. However, burning has other with follow up work. Resources will mechanical removal, hand pulling, impacts. Native plants will have been be needed over the long term to re­ herbicide treatment or fire. Once affected and some broom plants may establish vegetation through natural Scotch or Montpellier broom is well survive and resprout more rapidly. regeneration or planting. established in native vegetation, Decisions about if and when to burn restoration through natural regeneration Chemical control is difficult to achieve, particularly in require careful consideration of a range older stands, where dense broom of issues and consultation with fire Herbicide can be highly effective, prevents replenishment of the native authorities. Stands of broom should providing it is carefully chosen and rootstock and seedbank. only be burnt as a component of a selectively applied to minimise regrowth comprehensive long-term vegetation and off-target damage. The main The key to successful management management plan. Native and weed herbicide treatments for brooms are of brooms is to integrate a range of species need to be managed when foliar spray, cut-stump, stem injection treatments tailored to the situation, targeting regrowth of broom. and basal bark application. All of these including biological control where Repeated fires at short intervals would methods are only effective if the plants available. Perseverance is required, have unpredictable impacts on natives. are actively growing at the time of with consistent effort over the long Fire, whether planned or unplanned, application. While more labour intensive term to create conditions in which should be followed up with different than foliar spray, stem treatments of

Weed Management Guide • Scotch broom – Cytisus scoparius and other introduced brooms 8

long-established plants are dependable Cut-stump application and minimise off-target damage. Suitable for all basal stem sizes Limited information is available on the most effective treatments for the less All stems are cut horizontally with common brooms. secateurs, bush saw or a chainsaw no higher than 15 cm from the ground and Foliar spray the cut surface painted immediately (within 10 seconds) with herbicide, For spraying to be effective, all weed Stem injection. Side view of trunk showing using a hand-held spray bottle or a 45°-angled holes in sapwood. foliage must be wetted and the brush. For large infestations, a team equipment suited to the size of the of two or more people need to work plants. In native vegetation, careful spot and sideways. Holes need only be as together. Use a dye in the mixture to spraying using hand-held equipment deep as the living wood just under the show that stems have been treated. (handgun and hose or knapsack) would bark. Fill immediately with herbicide be required to avoid off-target damage. Preliminary trials have indicated that using a squirt bottle or plastic syringe. In this situation, foliar spraying is cut-stump herbicide application is an generally limited to small plants and effective treatment for mature plants Basal bark application of white weeping broom. regrowth under conditions when spray For basal stem diameter up to 5 cm drift will not occur. Stem injection Bark of all stems needs to be sprayed Foliar spray is most suitable where or painted with suitable herbicide around For basal stem diameter larger a carpet of broom seedlings appears the entire circumference to a height than 5 cm after disturbance. Native plants need of at least 30 cm from ground level. to be located and shielded from Drill holes at approximately 5 cm intervals spray contact. around the stem, angled downwards

Registered herbicides should have formal training in the safe and Veterinary Medicines Authority for brooms storage, handling, preparation and use website to find the relevant permit for of the chosen herbicides. Particular care your state or territory and obtain advice Various triclopyr products are registered should be taken near waterways because on local conditions from the permit for foliar spraying Scotch (English) rainfall runoff will carry herbicides. holder. Refer to the fact sheet ‘Off label broom or Genista spp. in spring to mid Use special formulations for such chemical use in Victoria’ for sources summer prior to pod formation. Foliar environments where appropriate. of advice in that state. – Cytisus scoparius and other introduced brooms spot spray of Scotch broom is also Research is underway comparing included on the label for aquatic Alternative methods chemicals and methods for controlling formulation of glyphosate. Triclopyr of applying glyphosate white weeping broom in SA with applied via basal bark or cut stump a view to applying for a minor use treatment is listed on labels for Tas. Cut-stump application and stem permit. Refer to contacts table for Scotch broom Scotch broom only. These herbicides are translocated injection of glyphosate for brooms are current information. and are not herbicide active in the soil. not included on registered labels. A Glyphosate is not selective and can ‘Permit to allow minor use of an AGVET Where covered by a permit non­ affect any type of plant and Triclopyr chemical product’ may be issued to residual, systemic chemicals are often affects plants other than grasses. Other allow registered products to be used applied to individual weed plants mixtures are also registered for particular for a purpose or in a manner that is not in native vegetation by community brooms but soil-residual herbicides included on the approved label. Permits groups, landholders and public land involve greater risk in native vegetation. that include stem treatment of brooms managers. with glyphosate in some situations exist When using herbicides always read the in Tas., WA, Qld, SA, NSW and the label and follow instructions carefully. ACT. Refer to the Australian Pesticides At least one member of a group

Weed Management Guide • Scotch broom – Cytisus scoparius and other introduced brooms 9 ...case study Controlling broom after major fires in the Victorian Alps

Scotch (or English) broom (Cytisus scoparius) has been present in the Victorian Alps for many decades and is actively invading native subalpine vegetation, where it is a major threat to biodiversity. Parks Victoria, manager of the Alpine National Park, has an ongoing strategy for containing broom and minimising its impacts with the following main aims: • eradicate isolated broom populations • progressively remove broom from catchment headwaters and other high value sites

• keep seed-bearing broom plants away Scotch broom from roads and tracks to minimise spread by vehicles and walkers. Dense regeneration of Scotch broom (Cytisus scoparius) in competition with native understorey After extensive wildfires in January 2003, after the 2003 fires in the Victorian Alps. broom germinated from the seedbank Photo: Parks Victoria forming dense thickets, and where the – Cytisus scoparius and other introduced brooms fires were most intense the seedbank • targeting isolated broom patches during the first spring, 9 months was diminished. The fires also destroyed recorded using GPS post-fire, may have resulted in even populations of broom-feeding insects • reintroducing the biocontrol agent, greater control effectiveness. There that had been introduced as potential the twig-mining moth (Leucoptera were differences in the impacts of biological control (biocontrol) agents. spartifoliella) treatments on broom stands, however Parks Victoria recognised that the area, • community workshops and none of the herbicides resulted in a density and impact of broom infestations involvement of private landholders, total broom kill. in the region would greatly increase landcare groups and schools. After 3 years there were changes to if these new thickets were allowed to This last point recognises that native vegetation across all sites, in produce seed. A major collaborative communication and consultation are both treated and control (untreated) program was put in place to tackle the vital to coordinate weed control across plots. Herbaceous species were the task of minimising this replenishment. property boundaries and to ensure that most susceptible growth form, both to Partners in the program, coordinated biocontrol agent release sites are not increasing broom density (in unsprayed and led by Parks Victoria, include state inadvertently damaged by spraying or plots) and to herbicide application, and government agencies, the catchment controlled fires. Monitoring outcomes their cover and richness decreased. management authority, community and adapting the management Perseverance with the trials and the recreational organisations, local program are also essential. collaborative program, informed by government, private landholders and continued monitoring of the results sponsors. Early herbicide trial results found that commencing spraying in the autumn, (~10% of the costs) is needed to find The program included: 15 months after the fires, was more effective ways to contain the spread • trials of the effectiveness, timing and effective and less expensive than of broom and minimise its impacts on cost efficiency of three herbicides commencing the following spring, biodiversity. The search for effective sprayed at label rates including 21 months after the fires. This remained biocontrol agents continues and a glyphosate aquatic formulation the case in 2005 and 2006, indicating planning is advanced to introduce • monitoring to evaluate which plant the benefits of early commencement the broom gall mite (Aceria genistae) species regenerate after weed removal of treatment post-fire (2007 data are later in 2008. • applying control techniques more currently being analysed). It is possible widely if they were successful in trials that a commencement of spraying

Weed Management Guide • Scotch broom – Cytisus scoparius and other introduced brooms Scotch broom – Cytisus scoparius and other introduced brooms tailored toyoursituation. of NationalSignificanceandAlertListspecies.TheIntroductory Weed ManagementManual(alsoavailablefrom thiswebsite)mayassistindevelopingaplan Refer totheCRCforAustralianWeed Managementwebsite (www.weedscrc.org.au) forweedmanagementguidesinthisseries,aswell asguidesforWeeds community groups working onbrooms. Consult thenaturalresource managementorganisationforyourregion orlocal counciltofindlocalcontactsonmanagingweeds for biodiversity, including database whichcontainsinformationonallherbicidesthatare registered foruseonweedsineachAustralian stateandterritory, includingminorusepermits. Contact detailsforstateandterritoryagencieswithresponsibility forweedsare listedabove,alongwiththeAPVMA.TheAPVMA websitehoststhePUBCRIS Conservation Act1995 . Conservation under theNSW ThreatenedSpecies broom isakeythreatening process Invasion andestablishmentof Scotch noxious weedsreview.in theVictorian Spanish broom are under consideration prohibited. WhiteSpanishbroom and white Spanishbroom toTas. are broom andspinybroom toWA and in Australia).Introduction ofScotch the table:Naturalisedbroom species and toapplyquarantinemeasures (see of speciesthathaveamajorimpact with theaimbeingtorequire control declared weedsinoneormore states In total,fivespeciesofbroom are a stateorregional level. all ofwhichare declared weedsat G. linifoliaandCalicotomespinosa, scoparius, Genistamonspessulana assessment. Exceptionsare Cytisus to Australiawithoutpriorweedrisk hybrids are permittedentry asseeds a widerangeofbroom species and Under nationalquarantinelegislation Legislation Contacts Weed Management Guide • Scotch broom– Australia-wide Territory State / NSW ACT Tas. WA Qld Vic. SA Australian PesticidesandVeterinary Medicines Authority(APVMA) Dept ofAgriculture andFood Dept ofPrimaryIndustries Dept ofPrimaryIndustries Dept ofPrimaryIndustries Dept ofPrimaryIndustries Dept ofEnvironment and Biodiversity Conservation Dept ofWater, Landand Dept ofSustainability Dept ofTerritory and Municipal Services and Environment Climate Change Department and Fisheries and Water Acknowledgments may beregulated bylegislation. significantly damagenativevegetation to gardeners. Broom control thatcould declared brooms maystillbeavailable relevant toyourlocation). However, (see thetableaboveforfurtherdetails minimise spread intouninfested areas term programs toreduce impactsand all landholdersincoordinated, long­ legislation encouragesinvolvementof Where brooms are widespread weeds, avh.cgi www.rbg.vic.gov.au/cgi-bin/avhpublic/ of AustralianHerbaria. Gardens Councilof Heads Melbourne, monspessulana), viaRoyalBotanic ( Map: Australia’s Herbarium, Virtual M. Keatley, ParksVictoria. Case study:C.Pascoe,P. Dowerand SA DWLBC. Hosking, NSWDPI;DrJ.G.Virtue, Information andguiderevision: DrJ.R. Cytisus scopariusandGenista (08) 83039620 (08) 93683333 (02) 62104700 1800 680244 1300 368550 132281 131555 132523 136186 Phone 10 Cytisus [email protected] [email protected] [email protected] [email protected] [email protected] scoparius [email protected] [email protected] Email N/A N/A N/A and other introduced brooms information References and further weed_man_guides.html www.weedscrc.org.au/publications/ Systems. Adelaide, SouthAustralia. C. scoparius.CRCforWeed Management Best practicemanagementguide: broom CRC forWeed ManagementSystems(2000). weed_man_guides.html www.weedscrc.org.au/publications/ Management, Adelaide,SouthAustralia. (Retama raetam).CRCforAustralianWeed management guide:whiteweepingbroom broom (Cytisusmultiflorus)andWeed Weed managementguide:whiteSpanish (2003). AlertListforenvironmental weeds: CRC forAustralianWeed Management www.tropicalforages.info/index.htm Australia. selection tool.CSIRO,QDPIF, Brisbane, factsheet. InTropical Forages:aninteractive Chamaecytisus prolifervar. palmensis Cook, B.G.andPengelly, B.C.(eds)(2005). www.frli.gov.au/ F2006L04007. AustralianGovernment. 2006 (No.7).LegislativeInstrument— Quarantine AmendmentProclamation AQIS PermittedSeedsList(2006). www.environment.nsw.gov.au www.dpi.nsw.gov.au/weeds www.tams.act.gov.au/live/ www.dwlbc.sa.gov.au www.agric.wa.gov.au www.dpiw.tas.gov.au www.dpi.qld.gov.au www.dse.vic.gov.au www.apvma.gov.au www.dpi.vic.gov.au environment Website 11

CSIRO Entomology resources: Biological control of Montpellier broom fact sheet www.csiro.au/science/CapeBroom Biocontrol.html Biological control of Scotch broom fact sheet www.csiro.au/resources/ps226.html

Department of Primary Industries, Victoria (2006). Identifying Victorian Alert Weeds; Tackling Weeds on Private Land. Department of Primary Industries, Victoria. www.dpi.vic.gov.au/weeds

Department of Primary Industries, Victoria resources: Information notes: biological control. www.dpi.vic.gov.au Montpellier broom (Genista monspessulana) invading regrowth eucalypt woodlands, Mt Lofty Ranges, SA. Dewar, A.M., Facelli, J.M., Marschner, P., Photo: Peter Martin Smith, F.A. and Panetta, F.D. (2006). Gorse Scotch broom and broom in the Adelaide Hills: effect of Kang, M., Buckley, Y.M. and Lowe, A.J. Wearne, L., Allan, C., Keatley, M. and invasive species on soil microbial biomass (2007). Testing the role of genetic factors Dower, P. (2007). Is management effective? and nutrients. In C. Preston, J.H. Watts and across multiple independent invasions of The results of an adaptive experimental N.D. Crossman (eds). Proceedings of the the shrub Scotch broom (Cytisus scoparius). management program to determine best 15th Australian Weeds Conference. Weed Molecular Ecology 16:4662–4673. practice chemical control on Cytisus

Management Society of South Australia, scoparius and impacts on native vegetation. – Cytisus scoparius and other introduced brooms Lloyd, J. (unpubl.). Biology and Adelaide, pp. 203–206. 9th International Conference Ecology and management of Genista monspessulana (L.) management of Alien Plant Invasions. Emms, J., Virtue, J.G., Preston, C. and L.A.S. Johnson (Montpellier broom). PhD www.hear.org/emapi/2007/ Bellotti, W.D. (2006). Is Retama raetam thesis, University of Adelaide, South (Forsskal) Webb a legitimate Alert List Australia, 2000. Weeds in Australia. Web resource: species? In C. Preston, J.H. Watts and N.D. www.weeds.gov.au/identification/index.html Sheppard, A.W., Hodge, P., Paynter, Q. and Crossman (eds). Proceedings of the 15th (Use links to search for weed species). Rees, M. (2002). Factors affecting invasion Australian Weeds Conference. Weed and persistence of broom Cytisus scoparius Western Australian Herbarium (1998–). Management Society of South Australia, in Australia. Journal of Applied Ecology FloraBase—The Western Australian Flora. Adelaide, pp. 735–738. 39:721–734. Department of Environment and Fogarty, G. and Facelli, J.M. (1999). Growth Conservation. Sheppard A.W., Hosking, J.R., Sagliocco, and competition of Cytisus scoparius, an http://florabase.dec.wa.gov.au/ J-L., Thomann, T., Downey, P.O. and Kwong, invasive shrub, and Australian native shrubs. R.M. (2006). Biological control of brooms Plant Ecology 144:27–35. in Australia: an update. In C. Preston, J.H. Knowledge gaps Harden, G.J. (1993). Flora of NSW. Volume Watts and N.D. Crossman (eds). 3. NSW University Press. Proceedings of the 15th Australian Weeds Little is known about the biology Conference, Weed Management Society of the less common broom species Hosking, J.R., Smith, J.M.B. and Sheppard, of South Australia, Adelaide, pp. 573–576. and methods for their control. Few A.W. (1998). Cytisus scoparius (L.) Link ssp. comparative studies have been scoparius. In Panetta, F.D., Groves, R.H. Walsh, N.G. and Entwisle, T.J. (eds) (1996). undertaken on native vegetation and Shepherd, R.C.H. (eds). The Biology Flora of Victoria Volume 3: Dicotyledons of Australian Weeds. Vol. 2. R.G. and F.J. (Winteraceae to Myrtaceae). Inkata Press. invaded by broom that would assist Richardson, Melbourne, pp. 77–88. in predicting the response of native Wearne, L.J. and Morgan, J.W. (2004). plants as well as brooms to various International broom initiative resources: Community-level changes in Australian management options. Such www.cal-ipc.org/ip/research/biocontrols/ subalpine vegetation following invasion information is needed to enable the broom/index.php by the non-native shrub Cytisus scoparius. most appropriate actions to be Journal of Vegetation Science 15:595-604. Jessop, J.P. and Toelken, H.R. (eds) (1986). planned for each site at all stages Flora of South Australia. Part II. Handbooks Wearne, L.J. and Morgan, J.W. (2006). in a broom management program. Committee, Adelaide. Shrub invasion into subalpine vegetation: implications for restoration of the native ecosystem. Plant Ecology 183(2): 361–376.

Weed Management Guide • Scotch broom – Cytisus scoparius and other introduced brooms Quick refer ence guide

Regional / local status of brooms Not yet established Small, isolated outbreaks Widely established Management Prevent establishment Eradicate Contain infestations and mitigate threats goals Strategies Practise weed hygiene Do not allow young stands Native vegetation: required Raise community awareness to seed Identify high priority biodiversity assets under threat from brooms and capacity to recognise Treat manually or using Protect them through implementing long-term site the weeds and the problem herbicide with minimal management plans Monitor, detect and identify disturbance Public and private gardens: possible new infestations Follow up Replace any known weedy species Prevent re-establishment Monitor specimens of other brooms and remove if seedlings found or invasion by other weeds Roadsides and other corridors: and encourage natural Map infestations and practise weed hygiene to prevent spread regeneration of native along and from roadsides into native vegetation vegetation Pastures: Options may include mulching (not bulldozing) or strategic grazing to restore broom-infested pastures

Vegetation management Apply herbicides during Prevent broom or weed control? periods of active growth re-establishment

Adopt a strategic, integrated, long­ Herbicide should be applied when Once fruiting plants have been term approach to maximise restoration plants are leafy and actively growing, killed, the focus is on preventing of native vegetation and minimise preferably before seeds mature. Avoid re-establishment of stands and reinvasion by broom or other weeds. hot or wet conditions, or periods when replenishment of the seedbank. A few Natural regeneration of native plants plants are under stress, as specified germinating seeds can quickly produce is the best form of revegetation, but in on the herbicide label. a large infestation if neglected, so sites dominated by broom over many ongoing surveillance will be needed. years, there may be no native plants or Consider disposal options – Cytisus scoparius and other introduced brooms seed remaining. Where this is the case, • Avoid large-scale disturbance that establish a range of indigenous plants. would create extensive areas of bare Cut broom should not be left on top soil, such as too-frequent fire in native of native vegetation. Cut stems bearing Adapt the control viable seeds should be collected and vegetation or overgrazing in pasture. method to the situation removed or heaped and carefully burnt, • Identify likely broom seed sources, ensuring no viable seed remains. dispersal agents and patterns of Scotch broom Scotch broom Brooms occur in a range of invasion. environmental conditions and land uses. • Monitor broom-free areas every Mulching, grazing or repeated use of Follow up 2 years at the start of the flowering fire may be appropriate in introduced pasture but would be unlikely to assist It is essential to monitor for regrowth season to detect and remove regeneration of native vegetation to from stumps after physical or chemical seedlings and young plants before replace broom. treatment and follow up thoroughly. they seed.

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