The broom plant (Cytisus scoparius) grows as a hardy, deciduous flowering shrub. Thin branches arch upward, reaching maximum heights of 6 feet. In the spring, the shrub becomes covered with small, bright yellow flowers. Also known as Scotch broom, this prolific bloomer makes an attractive choice for home gardeners who want a showy, low-maintenance shrub. Unfortunately, Scotch broom also spreads rapidly and may become invasive.