Money plant (Lunaria annua), also known as “Honesty”, is an herbaceous biennial in the mustard family (Brassicaceae). It is usually grown for the coin-like, silvery, translucent seed pods that are used in dried flower arrangements. However, the colorful effect of the magenta flowers from a grouping of plants is quite magnificent. The ½-inch flowers are pleasantly fragrant and make for excellent cut flowers. There is also a less commonly encountered white-flowered variety.
It is a biennial because the next year the seeds germinate and produce small plants. That will be year one in the biennial life cycle. In the early spring of the following year (year two), multiple flower stalks arise on each plant and grow to 3 feet tall. These flower stalks, called racemes, are covered in intense, pinkish-lavender flowers that last for 2 to 3 weeks. Each flower has 4 petals. After flowering, this biennial plant will die. Unless the seed stalks are collected, the silvery seed pods will remain in place to add autumn interest to the woodland setting as they slowly disperse their seeds. These flowers are pollinated by long-tongued bees and butterflies.
Money plant grows best in fertile, well-drained woodland soils. It prefers dappled sunlight or partial shade, such as along the edge of woods. It has coarsely-serrate, pointed, oval-shaped leaves, which combine well with spring-blooming plants having fine-textured foliage, such as Christmas fern, daffodils, native columbine, dwarf-crested iris, and green and gold.
Money plant will self-seed and produce seedlings that appear the following spring. In order to have flowering plants each year, as opposed to every other year, save some of the seed to plant the next year in late summer. To spread the plant over new areas, break off the dried flower stalks and scatter them over the woodland area. An excess of matted mulch may prevent seed germination, but they will typically come up in woodland leaf litter. Fertilize plants in the spring after new growth begins and use a slow-release fertilizer or complete organic fertilizer.
To save the dried seed pods, which are botanically called silicles, for use in flower arrangements, collect and tie together a bunch of flower stalks and hang them upside down for 2 to 4 weeks until dry. The brown outer coverings on each side of the seed pods can be easily removed by gently rubbing pods between the thumb and finger. Seeds can be caught and kept dry until future planting.
Money plant is easily confused with dame’s rocket (Hesperis matronalis), which is also in the mustard family, a biennial and has the same color flowers. Dame’s rocket is an aggressive reseeder, has escaped from cultivation and become invasive in some parts of the United States. It may quickly colonize wet sites having rich soil. Its spread is partially attributed to being included in many wildflower seed mixes. Dame’s rocket is a non-native plant from Europe, Siberia and China. This invasive plant flowers later in the spring than money plant, its leaves are longer and narrower, and the seed pods are long and slender as compared to the rounded seedpods of money plant.