Potentilla simplex - Perennial. Height 15-25 cms, 50 cms width. Full sun to part shade. Bright yellow buttercup like flowers, which close at night. Medicinal plant for both humans and animals.. Used medicinally by the Ancient Greeks. Will grow in most moist well drained soil types. Very attractive foliage. An easy to grow plant.  Tolerates cold weather. Frogs are said to be attracted to this plant.