Clematis can be deciduous or evergreen shrubs or herbaceous perennials, mostly climbing by twining leaf-stalks, and often with showy flowers. Some have attractive fluffy seed-heads in autumn
Montana Group clematis are vigorous deciduous climbers with single, 4-petalled flowers opening in late spring and early summer
C. montana var. grandiflora is a very vigorous large deciduous climber with trifoliate leaves. Single pure white flowers to 7cm across from late spring to early summer with occasional later flowers.