Lunaria, or money plant, is a member of the Brassicaceae family that is noted for its papery dried seed pods. They are biennial in habit, meaning they produce green, leafy growth the first year and flowers the next. The silvery seed pods are used in dried flower arrangements and can last for years. A European native that is now established throughout much of North America, it grows wild in many areas. It is also known as dollar plant, annual honesty, perennial honesty and silver dollar.
The four-petaled flowers of the lunaria plant are violet in color, highly fragrant, and bloom throughout the early summer in clusters atop a single stem. They have a habit of fading as they mature, making them appear lavender or nearly white. The leaves are large, deep green and toothed, and grow in a clump close to the ground and up the stem. These are good garden plants for beginners, because they are extremely easy to grow and are not picky about soil or sunlight.
This ornamental plant grows to 2 feet tall (0.6 m) or more and can be top heavy, making it prone to toppling over in windy conditions. Staking can help prevent this from happening. It also has shallow roots and may need to be replanted deeper in the soil to increase stability and to help prevent the roots from drying out.
Lunaria is unusual in that it is commonly planted not for its flowers but for its seedpods. After the flowers have gone in midsummer, flat green seedpods begin to appear. They are about 1 inch in diameter (2.5 cm) with from three to six large flat seeds visible inside each one. As summer goes on, they turn a silvery tan color and become more transparent. The pod splits and the seeds turn brown, dropping onto the ground to sprout the following growing season, and leaving thin, ornamental, coin-like circles behind on the stalks.
Once lunaria has been around for a few years, it will begin appearing everywhere, because it spreads readily. It transplants well, making it easy to move plants when they grow where they are not wanted. They will continue to spread each year but not to the point of becoming invasive like its cousin Hesperis matronalis, or Dame’s Rocket. While they are members of the same family of flowering plants and they are similar in appearance, lunaria does not colonize into large swarms of plants as hesperis does.