Yellow Loosestrife (Lysimachia punctata)
Yellow Loosestrife does best in full to dappled sun and moist soil with plenty of humus or organic material. In nature it is native to wetland areas in Europe and Asia. This herbaceous perennial is hardy in zones 4-8. Yellow Loosestrife blooms in summer and grows 2 to 3 feet tall.
Loosestrife can grow in large clumps and looks good with other plants especially cranesbill geranium which blooms at the same time. After blooming I prune stems to the ground.
To increase, dig up clumps of them in early spring before the soil warms up