'Thriller' Lady's Mantle blooms in May and June, producing airy delicate chartreuse yellow flowers held above fuzzy bluish green leaves. 'Thriller' has somewhat larger pleated leaves and a more prolific bloom than the species, and like all Alchemilla mollis, the hairy leaves repel rain water so that the foliage has attractive silver water drops on if after a gentle rain. 'Thriller' performs best in shady, moist conditions.