'Mrs. Cholmondeley' is an early and large flowering, deciduous Clematis cultivar. It is a vigorous, medium-sized climber that produces single, starry flowers measuring around 20cm across, this occurs from late spring to late summer. Flowers have 6 pale lavender-blue, rounded sepals, which strongly resemble petals but with a protective rather than decorative function. The sepals are deeply veined along the midribs, paler in colour and there are white-chocolate brown coloured stamens in the centre.