Just one type of currency, though: silver dollars (Lunaria annua).
You have a couple of options for planning your investment. For quickest returns, sow seed indoors in a seedling flat filled with moist potting soil. Kept at about 70 degrees Fahrenheit, the seeds germinate within two to three weeks. Plant the seedlings outdoors at the same time you plant out tomatoes, then harvest your first dollars later this summer. If you plant very soon, you may still be able to get a return on your investment this year.
Despite the "annua" in the botanical name, however, silver dollar plant often behaves more like a biennial than an annual, growing only leaves the first year then expiring the next year after making flowers and dollars.
The second, more relaxed way to grow silver dollar plant is as a biennial. Sow the seeds outdoors sometime in early summer — timing is not critical — to rake in your dollars early next summer.
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Whichever method you choose, give silver dollars a site with well-drained soil in sun or partial shade. Avoid a rich soil, though, or plants put their energy into making leaves at the expense of flowers and dollars.
MORE THAN JUST SILVER DOLLARS
The flowers that foreshadow the silver dollars are pretty, but not enough to warrant giving the plant a prominent spot in your flower bed. A better location is in a separate cutting garden, a wild area, or nestled — and somewhat lost — among other kinds of flowers.
The money plant's flowers have four petals in the shape of a cross, putting it in the Mustard Family, along with broccoli, radish and alyssum. Usually, the flowers are pink or purple, except for one variety with white flowers. For a little more pizazz, there is a variety, Variegata, with white margins on its leaves.
Silver dollar plant, along with other members of the Mustard Family, ripens its seeds within a dry fruit called a silique. As the silique ripens, the two outside halves dry, then fall away to leave the ripened seeds still on the plant and suspended within a translucent and silvery round septum, about the size of a silver dollar.
For dried flower arrangements, cut stems just as the outsides of the pods are beginning to yellow, then hang them upside down in an airy location. Once the outsides dry, rub them off with your fingers without damaging the delicate membrane between them.
AN INVESTMENT IN 'HONESTY'
You might say the silvery orbs that remain also resemble the moon, leading to another common name for the plant, moonwort, as well as the botanical name Lunaria.
And money and honesty go hand in hand, right? Perhaps that's how silver dollar plant also came to be called "honesty." Some people say it got that name because you can actually see the seeds within the ripened fruits.
Your initial investment in silver dollar plant can be made with seeds from a seed packet, or with seeds snatched from a dried arrangement. You will get compound interest on your initial investment because silver dollar plant self-sows. Too readily in some situations, so put your investment where you can keep a close eye on it, or where other equally exuberant plants can help check its spread.