Scotch Broom (Cytisus Scoparius) Scotch Broom (Cytisus Scoparius) ● Cape Broom and Other Introduced Brooms (Genista Monspessulana)

Home , Calicotome, Cytisus, Cytisus multiflorus, Cytisus scoparius, Genista linifolia, Genista monspessulana

Managing weeds for biodiversity

Recorded distribution: ● Scotch broom (Cytisus scoparius) Scotch broom (Cytisus scoparius) ● Cape broom and other introduced brooms (Genista monspessulana)

The problem Scotch broom and Montpellier broom White weeping broom (Retama raetam) are promoted by disturbance but are and white Spanish broom (Cytisus Brooms are shrubs in the pea family spreading into intact native vegetation. multiflorus) are on the Australian Alert (Fabaceae) that are widely cultivated They outcompete native understorey List because they currently have a Scotch broom for ornamental or other purposes. A through their rapid growth rate and limited distribution but have potential number of species, mostly native to high seed output, increase soil fertility to become threats to biodiversity. They Europe or Africa have been introduced and dominate the soil seedbank. It is are the subject of their own weed to Australia and become weeds. particularly difficult to restore native management guides under the Alert Scotch (or English) broom (Cytisus vegetation long invaded by brooms. List series. These and other brooms are – Cytisus scoparius scoparius) and Montpellier (or Cape) Several insects that feed selectively still cultivated in gardens. Tagasaste (or broom (Genista monspessulana) are on Scotch broom plants or seeds have tree lucerne) (Chamaecytisus palmensis) widespread weeds that have formed been introduced to Australia, but their is commonly planted for fodder in WA major infestations in southern Australia. impacts have generally been limited. but is also a weed of native vegetation. Most studies of broom in Australia Biological control may become a useful have focused on these and they are tool, where it is integrated with other the main species profiled here. Other measures for long-term rehabilitation

Key points and other introduced brooms species that currently have a more of broom-infested sites, and for reducing limited distribution are covered in less spread. Research has also commenced • Broom species invade native vegetation in detail but may be of equal or greater into organisms with potential for southern Australia, some are widespread and threat in certain situations. controlling Montpellier broom. others localised at this stage. • They can grow rapidly, outcompete native plants and increase soil nitrogen. • Brooms reproduce from seed and plants resprout if damaged. They often form a long-lived seedbank. • Biological control agents have been released for Scotch broom. • Removing broom stands generally creates conditions that initially promote the weed. To restore native vegetation, it is necessary to take this into account. • It is most effective to remove plants before they seed and before broom replaces native plants. • Correct weed identification is essential. Some Scotch broom (Cytisus scoparius) is invading native woodland at high elevations in the Australian native plants resemble brooms. Alps. Its seeds are carried by people, native and introduced animals (including stock), vehicles, • Many broom species, cultivars and hybrids machinery and water. Detection and removal of isolated patches is a management priority. Photo: Parks Victoria are commonly grown, mainly in gardens. 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 and other introduced brooms 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 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 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, and other introduced brooms 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 4

Naturalised broom species in Australia: main species and features Distribution Vic. SA, Tas., NSW, ACT, Widespread in cool wet areas Origin: Macronesia, Europe Qld, SA, NSW, ACT, Vic. WA Tas., Widespread in southeastern Australia Origin: Mediterranean, Georgia Vic., WA SA, Tas., NSW, locations Scattered Origin: Canary Islands, Mediterranean W. Qld, SA, #NSW, ACT, #Vic. Tas., Localised, uncommon Origin: Azores, Mediterranean, Caucasus Vic. Localised, uncommon Origin: Mediterranean Legislation and notes NSW, in ACT, Declared Vic. SA, Tas., Quarantine weed in WA AQIS not permitted NSW, in ACT, Declared Vic. SA, Tas., AQIS not permitted in ACT, Declared Vic. NSW, AQIS not permitted NSW in ACT, Declared in Vic. Declared Quarantine weed in WA AQIS not permitted almost hairless; Seed pods oblong, Narrowly 25–70 mm long, hairy along the opening; up to 22 seeds oblong, Narrowly 15–30 mm long, densely hairy; 5–8 seeds oblong, Narrowly 13–30 mm long, densely hairy; 2–6 seeds 60–80 mm Slender, 6 mm long, approx. wide; becoming hairless; mostly with 10–15 seeds Oblong, 25–45 mm long; lower margin winged, 5–15 seeds Leaves Simple or 3 leaflets on a stalk; sparse; deciduous stressed when plants are 3 egg-shaped leaflets on a short stalk leaflets, 3 narrow 10–25 mm long, 0.5–4.5 mm wide; under margins rolled Simple, 10–30 mm long, 2–5 mm wide; sparse, may shed when plants stressed are 3 leaflets, 5–10 mm long, 2–5 mm wide; on a stalk up to 10 mm long and other introduced brooms Yellow but some Yellow naturalised hybrids have and yellow flowers, red 15–25 mm long; single or in pairs Mainly late winter to summer 8–13 mm long; Yellow, of usually in groups 3–7 on short branches Late winter and spring, sometimes late summer and autumn 10–15 mm long; Yellow, of 3–16 in groups Mainly in spring 20–30 mm long, Yellow, scented; in sprays, 5–20 flowered Spring to early summer 12–15 mm long; Yellow, in clusters of 1–5 Early summer (Nov—Dec) – Cytisus scoparius Habit Shrub 1–4 m tall; young branches 5-angled Shrub 1–3 m tall; stems ribbed Shrub 1–3 m tall; stems ribbed Shrub to 3 m to 5 m) tall; (rarely stems not ribbed Shrub to 3 m tall with rigid spines to 7.5 cm long; stems hairless ) Scotch broom Scotch broom ) ) ) ) monspessulana Calicotome spinosa Cytisus scoparius Genista Genista linifolia Spartium junceum Photo: Andrew Steed Photo: Andrew Scotch or English broom ( Spiny broom ( Species Flowers and season Photo: Matthew Baker, Herbarium Tasmanian Montpellier or Cape broom ( Photo: Jackie Miles and Max Campbell Flax-leaf broom ( Photo: Jackie Miles and Max Campbell Spanish or weavers broom ( Photo: Matthew Baker, Herbarium Tasmanian

Weed Management Guide • Scotch broom – Cytisus scoparius and other introduced brooms 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, Vic., WA. Vic., WA. Widespread Origin: Canary Island Vic. Localised, uncommon Origin: SW Europe SA, WA Localised Origin: Mediterranean, Middle East, Canary Islands 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),

dallimorei a relative of brooms, is a Weed of x Not declared R. monosperma Commonly planted for fodder in Tas. Declared Alert List species of horticultural Parent hybrids including C. Alert List species Bridal broom ( similar and is invasive in California Legislation and notes National Significance.

The main features of the broom species

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

Other broom species not covered Linear—oblong, mostly 40–60 mm long, 8–12 mm wide; densely mainly with hairy, 4–10 seeds Linear—oblong, 15–30 mm long, 4–7 mm wide, silky; mostly appressed with 3–7 seeds Obovoid, 15 mm long, 10 mm wide with a short point or beak; 1–2 seeds; either not opening at maturity or opening late Seed pods in the table: Dallimore’s Spanish broom (Cytisus x – Cytisus scoparius dallimorei) = Cytisus scoparius cv. ‘andreanus’ x Cytisus multiflorus is a WA Quarantine Weed.

Madeira broom (Genista stenopetala)

Leaves 3 leaflets 10–45 mm long on a stalk 3 leaflets to 12 mm long, 4 mm wide on a stalk, and simple leaves narrow, Simple, tiny, hairy; deciduous is naturalised but uncommon and localised in southeastern Australia.

It is sometimes confused with and other introduced brooms G. x spachiana (naturalised in Vic.). It is a shrub to 6 m tall with terminal sprays of yellow flowers.

Cream to white, Cream 15–20 mm long; in of 3–7 or more groups Winter and early spring White with a pink 10 mm approx. streak, long; 1–3 per leaf axil Spring White, 8–10 mm long, pinkish base, in clusters of 3–15 Mainly winter and spring Dyers broom (Genista tinctoria) was recorded in Victoria but is probably not naturalised in Australia.

What to do about it Habit Shrub or tree to 5 m tall; branches hairy Shrub to 3 m tall; stems ribbed Shrub to 3 m tall, ‘weeping’ habit; hairy when young 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. Chamaecytisus Cytisus multiflorus Retama raetam Tree lucerne or Tree tagasaste ( palmensis Photo: Jackie Miles and Max Campbell White Spanish broom ( Nomura Photo: Yoshi White weeping broom ( Photo: John Virtue, SA DWLBC Species Flowers and season 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 6

Strategic weeding in native vegetation • Define priority areas for control by overlaying maps of weed density, Native vegetation Weeds native vegetation, site values and risks. • Plan to weed strategically: – protect the better quality native vegetation first and consider the needs of rare fauna and flora – work from isolated broom plants towards core infestations – control plants from upstream to downstream. Weed from the least weed-infested bush towards weed-dominated areas • The size of the area targeted at each stage should be manageable enough help contain spread and encourage Reduce established to follow up thoroughly. Seedlings native vegetation to recover. The capacity infestations: and regrowth need to be removed of a site to recover following broom before they replenish the seedbank. A planned, strategic approach is removal is affected by the condition • Include control of other weeds so essential to ensure that after treatment, and type of native vegetation and also that they do not establish where broom is replaced by desirable plant the age of the infestation. broom has been removed. cover rather than new broom seedlings, regrowth or other weeds. As well as • Select the most suitable control Assist with biological control the information presented in this guide method for each weed growth programs: on broom biology and control methods, stage to avoid damage to native Community groups and schools can a plan needs to be based on specific vegetation. Plan appropriate disposal sometimes be involved in the raising, knowledge about the site—including of weed material. distribution and monitoring of biological the distribution of other major weeds. • Prepare a weed management control agents. For opportunities to calendar to maximise the Develop and implement a long-term assist in these efforts, departmental effectiveness of control activities and other introduced brooms weed management plan. details are listed in the contact table. including avoiding the breeding 1. Investigate the site seasons of key native species.

Prevent brooms spreading: • Identify all plant species: weeds 3. Implement the action plan including all brooms and native Identify locations where broom occurs • Remove broom from the least plants that need protecting. as isolated plants or sparse populations. infested areas into the more infested • Map weed infestations: indicate Remove seedlings and treat isolated areas. Minimise soil disturbance and

– Cytisus scoparius weed density throughout the site, plants or clumps first and follow up. ensure that activities do not spread identify major sources of seed from Keep uninfested areas free of broom the seed. Adapt to local seasonal which re-invasion can occur. and prevent additional weed species conditions. • Map native vegetation condition: establishing in the region. Isolated • Follow up broom regrowth each year assess its capacity for recovery after plants are most easily detected when in areas previously treated before broom is removed and identify sites Scotch broom Scotch broom flowering, generally in spring. Accurate moving further into the infestation. of high biodiversity value, such as identification is essential as some native • Coordinate control programs with rare flora. species may look similar to brooms. neighbouring landholders to • Values and risks: identify native Raise community awareness of weedy maximise effectiveness and reduce fauna habitat values and high-risk brooms. A number of the naturalised ongoing spread. sites for erosion potential and species are still available for sale, are other factors. 4. Monitor and evaluate outcomes not always labelled consistently and and adapt the plan accordingly some cultivated forms have been 2. Develop the site action plan Include monitoring of native plant known to spread. Provide information • Identify goals and priorities based regeneration. In weed management on alternative non-weedy plants, on the site information. programs there is often a tendency particularly local native species that to focus on the removal of weeds as are available for gardens.

Weed Management Guide • Scotch broom – Cytisus scoparius and other introduced brooms Scotch broom – Cytisus scoparius and other introduced brooms treatments to selectively remove broom selectively remove to treatments natives. among regenerating Chemical control Herbicide can be highly effective, chosen and it is carefully providing selectively applied to minimise regrowth damage. The main and off-target are for brooms herbicide treatments cut-stump, stem injection foliar spray, and basal bark application. All of these if the plants only effective methods are at the time of actively growing are labour intensive application. While more of stem treatments than foliar spray, Physical weed removal an effective Hand pulling can be or isolated small method for removing vegetation. plants within native broom for only If a stand has been established before plants a few years, remove stands that seeding, but for older this seedbank have a broom already medium-sized is less critical. Small to plants can be hand pulled when the disturbance soil is moist, but the resulting light will lead of the soil and increased seed in to germination of soil-stored infestations. Hand weeding mature will be necessary or other treatment to continue the follow up work, while removing native plants. Avoid protecting seed if possible, plants carrying mature otherwise safe disposal is required. can be either bagged material Weed or heaped and carefully and removed, burnt on site, ensuring that no viable seed remains. areas In accessible, broom-infested such as non-native pastures, mechanical equipment may be used to plants with mulch non-seeding broom minimum soil disturbance. The layer of regrowth mulch may suppress broom assisting and seedlings temporarily, will with follow up work. Resources be needed over the long term to re- natural establish vegetation through or planting. regeneration and other introduced brooms and other introduced 7 Cytisus scoparius Fire Burning is often seen as an effective weeds such first stage in controlling the removes as hot fire as broom or plants and destroys above ground stimulates germination of soil-stored burning has other seed. However, impacts. Native plants will have been plants may and some broom affected rapidly. more survive and resprout Decisions about if and when to burn consideration of a range careful require of issues and consultation with fire should authorities. Stands of broom only be burnt as a component of a long-term vegetation comprehensive management plan. Native and weed species need to be managed when of broom. targeting regrowth at short intervals would Repeated fires impacts on natives. have unpredictable whether planned or unplanned, Fire, should be followed up with different Biological control to native Due to the major threat in south Scotch broom vegetation from eastern Australia, biological control for this agents have been introduced species. Several insects have become established in Australia but have not yet had a major impact on its infestations research recently, More or its spread. has commenced into biological control and potential of Montpellier broom agents have been identified. As these also major weeds in species are broom America and New Zealand, biological has involved research control international collaboration. native plants regenerate and the regenerate native plants declines. Methods seedbank broom on the major broom effective that are starting point generally the weeds are common species. for trials on the less appropriate methods may be Different amongst plants for sparse broom with native vegetation, compared dense, established infestations. ) Retama raetam Management broom – Scotch Guide • Weed Weed seedlings rapidly develop deep taproots and seedlings rapidly develop deep taproots survive dry conditions. Northern and Yorke Photo: D. Agnew, The key to successful management is to integrate a range of of brooms to the situation, tailored treatments where including biological control available. Perseverance is required, over the long with consistent effort conditions in which term to create Brooms are difficult to manage in difficult are Brooms native vegetation because they form rate, dense stands, have a high growth a large seedbank and generally produce the base. Seed may from resprout germinate in large numbers after hand pulling, mechanical removal, Once or fire. herbicide treatment is well Scotch or Montpellier broom established in native vegetation, natural regeneration through restoration to achieve, particularly in is difficult dense broom older stands, where of the native replenishment prevents and seedbank. rootstock Control methods NRM Board a goal, but at the site level the ultimate of native vegetation, goal is restoration for grazing pastures or productive properties. White weeping broom ( White weeping broom 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

and other introduced brooms 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 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 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 and other introduced brooms 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)may Refer totheCRCforAustralianWeed Managementwebsite(www.weedscrc.org.au) forweedmanagementguidesinthisseries,aswel community groups workingonbrooms. Consult thenaturalresource managementorganisationforyourregion orlocalcounciltofindcontactsonmanagingweeds database whichcontainsinformationonallherbicidesthatare registered foruseonweedsineachAustralianstateandterrito Contact detailsforstateandterritoryagencieswithresponsibility forweedsare listedabove,alongwiththeAPVMA.TheAPVM Conservation Act1995 Conservation under theNSW broom isakeythreatening process Invasion andestablishmentof Scotch noxiousweeds review.in theVictorian Spanish broom are underconsideration 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. linifolia scoparius assessment. Exceptionsare to Australiawithoutpriorweedrisk hybrids are permittedentryasseeds a widerangeofbroom speciesand Under nationalquarantinelegislation Legislation Contacts Weed Australia-wide Territory State / NSW ACT Tas. WA Qld Vic. SA aaeetGuide• Scotch broom– Management , Genista monspessulana and Calicotome spinosa Threatened Species 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 Cytisus and Water , , Acknowledgments avh.cgi www.rbg.vic.gov.au/cgi-bin/avhpublic/ of AustralianHerbaria. CouncilofHeads Gardens Melbourne, monspessulana ( 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. may beregulated bylegislation. significantly damagenativevegetation to gardeners. Broom control thatcould declared brooms maystillbeavailable relevant toyourlocation). However, (see thetableaboveforfurtherdetails minimise spread intouninfestedareas term programs toreduce impactsand all landholdersincoordinated, long- legislation encouragesinvolvementof Where brooms are widespread weeds, Cytisus scoparius (02) 62104700 (08) 93683333 (08) 83039620 1300 368550 1800 680244 136186 132523 131555 132281 Phone 10 ), viaRoyalBotanic yiu scoparius Cytisus and Genista [email protected] [email protected] [email protected] [email protected] [email protected] [email protected] [email protected] Email N/A N/A N/A and other introduced brooms Chamaecytisus prolifer Cook, B.G.andPengelly, B.C.(eds)(2005). www.frli.gov.au/ F2006L04007. AustralianGovernment. 2006 (No.7).LegislativeInstrument— Quarantine AmendmentProclamation AQIS PermittedSeedsList(2006). information andfurther References weed_man_guides.html www.weedscrc.org.au/publications/ Systems. Adelaide, SouthAustralia. C. scoparius.CRCforWeed Management Best practicemanagementguide: broom CRC forWeed Management Systems(2000). weed_man_guides.html www.weedscrc.org.au/publications/ Management, Adelaide,SouthAustralia. (Retama raetam).CRCforAustralianWeed management guide:whiteweepingbroom broom ( Weed managementguide:whiteSpanish (2003). AlertListforenvironmental weeds: CRC forAustralianWeed Management www.tropicalforages.info/index.htm Australia. selection tool. factsheet. Cytisus multiflorus In Tropical Forages:aninteractive www.environment.nsw.gov.au ry, includingminorusepermits. www.dpi.nsw.gov.au/weeds CSIRO, QDPIF, Brisbane, A websitehoststhePUBCRIS www.tams.act.gov.au/live/ assistindevelopingaplan for biodiversity, including www.dwlbc.sa.gov.au www.agric.wa.gov.au www.dpiw.tas.gov.au www.dpi.qld.gov.au www.apvma.gov.au www.dse.vic.gov.au www.dpi.vic.gov.au l asguidesforWeeds environment var. Website ) palmensis and Weed 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 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 other introduced brooms 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 reference 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 and other introduced brooms 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 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.

Disclaimer While every care is taken to ensure the accuracy of the information in this publication, the CRC for Australian Weed Management takes no responsibility for its contents, or for any loss, damage or consequence for any person or body relying on the information, or for any error or omission in this publication.