bush England english flowers garden Great Britain nature pink shrub Spiraea summer botany Bridewort flower flowering plant plant Terrestrial plant astilbe clusters color colored colorful colors colour coloured colourful colours cultivars dense false-goats-beard false-spiraea feathery feathery-plumes flower-clusters foliage herbaceous-flowering-plants hybrids long-blooming meadowsweet perennials plume plume-like-flowers plumes profuse profuse-blooms stalks