Honesty Money Plant (lunaria annua): Your plant appears to be a biennial that originated in Europe and is grown for its circular, coinlike seed pods. They don't appear until the second year. Spring flowers look like mustard blossoms, but are purple or white. It is a tough plant and reseeds readily, so be careful it does not overstep its area. Some people consider it a weed, but others value it as a garden plant. The choice is up to you! Needs full sun or afternoon shade and regular water.
