Spirea, Gold Thread™ Spirea, Mellow Yellow SpiraeaGold Thread Spirea is a twiggy upright arching deciduous shrub with willow like leaves that emerge yellow green and matures to bright green before turning coral orange in fall. Flat topped clusters of pure white flowers cover the plant in spring. Grows best in full sun and well drained soils. Removed spent flowers to encourage additional bloom. Syn. with Spiraea thunbergii 'Mellow Yellow'. Type: Shrub Origins: China and Japan Height: 4' 5' Spread: 5