Height: 2.5′-3.5′ Spread: 4′-6′. This tight, dense broom with bright yellow flowers in late May to early June was selected from the Alpine Gardens at Denver Botanic Gardens for its superiority to other brooms available because of minimal winterkill and the ability to thrive in heavy soils. Benefits from some winter water. Native to North Africa and Southern Europe. Full sun to part shade. Plant Select® 2000. Zone 5.