Genista monspessulana Genista Broom seed pods,when ripe,burst open ripe,burst of those to similar are flowers broom Scotch pods,when seed Broom inch-long fuzzy green seed pods fuzzy appear,turning green inch-long summer. in late dry and brown pod Each bears seeds. black shiny many to several broom,French and deeper larger they are but yellow. similar, Seed pods are too, that except seams, their on only hairs have they of instead fuzzybeing all over. from 12 feet to seeds up propel and explosively the plant. Starting in the of second year growth, seed production is prodigious; in a single plot,square-meter counted have researchers than 6,700 seeds! Furthermore,more seeds the persist, and years 5 least at viable for remaining decades. for potentially ger- seeds often Broom rains, winter with early minate a establishing offlush through December from seedlings new July. WEED WORKERS’ HANDBOOK WEED WORKERS’ (Spartium junceum) (Spartium (Genista monspessulana) monspessulana) (Genista (Cytisus scoparius) (Cytisus French broom usually grows 6 to 10 feet tall, 10 feet 6 to grows usually broom French tall. 10 feet 6 to grows also broom Scotch the from is distinguished broom Spanish ESCRIPTION EPRODUCTION Spanish broom (Fabaceae) Family Pea Legume or French broom broom Scotch BROOM SPECIES BROOM French broom flowers start to appear in March appear start to flowers broom French to and continue locations) in sunny (earlier July. even or yel- are They May through bloom low, less thansize, in a half-inch the have and with banner, shape pea flower familiar wing, petals.The main the and keel from grow flowers of in bunches stem 10. 4 to and July, June In R These three broom species are invasive shrubs invasive are species broom These three grasslands, in grow scrub,that woodland and habitats. introduced, Once can quickly they disturbed areas,colonize trailsides, stream- and banks, wildlandsinto and sometimes spread roads. shade along somewhat are species Broom tolerant, is broom Scotch in general though in drier,found locations. sunnier Individual shrubs have been known tolive up to 17 years. as tall as 15 feet. are can grow but plants Mature evergreen, coast. the along especially Leaves grow in groups of three. Each leaf long,half-inch is about woodlands. in shadier larger or a You ng pl a nt and by (see below) flowers the by broom sFrench are e a si ly stems. green dark their on ridges the d i Scotch st i ng u than French smaller and fewer are i leaves broom sh e d f rom broom, a wiry giving plant the look. typesother of smooth, its by broom round stems, single leaves, flowers. large and Leaves shedare during summer drought, giving a very appearance.stick-like can reach taproot Its depths of 6 feet, making the broom Spanish ofhardest remove. to brooms the three D

SHRUBS 64 IMPACT u Girdle the trunk of large broom plants with a Dense stands of broom change the structure of small hand tool such as a paint scraper. the invaded plant community, often increasing (Warning: while girdling minimizes soil dis- fire hazards by creating a “ladder” of woody turbance, standing dead broom will increase, material that can carry fire into trees. Brooms not reduce, fire hazards. Also, broom left provide poor forage for native wildlife. The standing will be in the way when you return leaves and seeds are toxic. As nitrogen-fixing for follow-up.) legumes, they can enrich soil nitrogen, which in u Scrape seedlings with a hula hoe. turn can promote the growth of other weedy u Flame seedlings in monoculture with a plant species once the broom has been removed. propane torch (weed blancher). This is most effective and efficient when the seedlings have KEY FACTORS only their two seed-leaves, but can also work u Prodigious seed production. on seedlings with true leaves, up to a few u Seeds remain viable for many years, poten- inches tall. (See Follow-Up for more on flam- tially decades. ing.) u Resprouts from stumps and root crown when

cut. SHRUBS FOLLOW-UP Wherever mature plants are removed, emerging TREATMENT OPTIONS seedlings will also have to be removed for at u Pull shrubs by hand or with a Weed Wrench,or least the next 5–8 years and probably longer. In dig with a Pulaski, pick, or shovel between the first year after removing mature plants, the January and May, when the moist ground next generation will be too small to pull,but this makes it easier to remove the roots,and before dense flush of seedlings is effectively controlled another generation of seeds has developed. by flaming with a propane torch. A single pass Repeated pulling of successive generations is with the torch will wilt and kill seedlings. currently thought to be the single most effec- Controlling broom plants when they are tive method of removing broom. seedlings will spare you a great deal of work in u Cut shrubs to just above ground level using a pulling plants the second year after removing pruning saw, loppers, or brushcutter, ideally mature broom. during the dry season so that the stumps Broom is not eradicated from your site until become more stressed. Cutting, rather than the seedbank is exhausted, so be vigilant to pre- pulling, has the advantage of minimizing soil vent subsequent generations from producing disturbance. Untreated cut stumps will seed. Broom is easiest to spot when the bright resprout and must be cut repeatedly (see yellow flowers are present, but be sure to remove Follow-Up, below.) Alternatively, cut the stems it before the seed pods mature. about 2 inches above ground level, then girdle Broom resprouts from the base when cut: all the stump by peeling the bark off the stems— except seedlings and old, senescent plants can like peeling a banana—down to ground level. resprout after cutting if not treated with herbi- This reduces resprouting and works best on cide. Resprouting stump shoots can be cut or medium to large French broom plants. weed-whipped the following year, either in late u Cut stems, using loppers, to about 2 inches spring or in the dry season. Repeat this treat- above ground, and grub out the roots. ment annually until the plants’energy resources u Cut and treat the stumps with herbicide. are depleted.

THE PLANTS: HOW TO REMOVE BAY AREA WEEDS 65 ACTS F NTERESTING I Mediterranean in the originates broom French Area Bay the to introduced reportedly and was 1800s. late mid- to in the as an ornamental Scotch broom is native to much of and Europe of foothills the Africa. North Putting broom-with-seed piles in deep shade in deep piles broom-with-seed Putting should Tarps germination. inhibit help also will bevisited annually, and eventuallyremoved decomposed. have materials when WEED WORKERS’ HANDBOOK WEED WORKERS’ Plants that have gone to seed should be piled ISPOSAL Notes Pulled plants that have not produced seed can seed produced not have that plants Pulled decompose. to be on-site piled Alternatively, recy- or chipped and off-site can be hauled they waste. as green cled use of innovative One pulled the bundle has been to waste broom plants to create 8- to 12-inch wattles that can be secured to slopes to erosion. prevent on tarps or bagged to reduce the number of germinating. and ground the to seeds falling D

SHRUBS 66 Notes SHRUBS

THE PLANTS: HOW TO REMOVE BAY AREA WEEDS 67