Typically known as lunaria or silver dollar plants, these iridescent "leaves" are actually the seed pods from the plant known as Lunaria annua. Lunaria plants are classified as biennials so you'll see a basal rosette of leaves during its first year and purple flowers or seedpods emerge the following year.
The seed pods that follow the silver dollar plant's flowers are known as "silicles." They start out green in color, later shedding the shade along with their seeds. The fully dried seed pod that remains (which is actually just a see-through membrane) is off-white in color with a sheen that makes it shine like a coin. These "silver dollars" are papery to the touch and not perfectly round but rather flat and oblong, with a short, needle-like projection that hangs down from the bottom of each seed pod. Plant lunaria in spring after the final frost—it will grow quickly, with seedlings emerging in just 10 to 14 days.
|Common Name||Lunaria, silver dollar plant, money plant, honesty, moonwort|
|Botanical Name||Lunaria annua|
|Plant Type||Herbaceous, biennial|
|Mature Size||2–3 ft. tall, 1–2 ft. wide|
|Sun Exposure||Full, partial|
|Soil pH||Neutral, acidic|
|Flower Color||Purple, pink|
|Hardiness Zones||5–9 (USDA)|
|Native Area||Europe, Asia|
Many gardeners plant lunaria along woodland borders, where they won't have to fuss with them. Though silver dollar plants are not perennials, they'll thrive and seed on their own as long as the conditions are right. Under the right growing conditions, one plant will eventually multiply into many plants, and it's their ability to re-seed that makes them such aggressive spreaders to the point of being invasive. However, if you're hoping to contain your lunaria collection, controlling the plant is straightforward enough.
Native to both Europe and Asia, lunaria is actually part of the Brassicaceae family, making them the relative of foods like broccoli and Brussels sprouts.
Lunaria plants do well in both full sun and partial shade locations. In a hotter summer climate, a bit of afternoon shade is appreciated, but ultimately the plant should get around eight hours of sunlight daily in order to grow strong roots and eventually flower.
Grow your lunaria plants in a friable, deeply cultivated soil to accommodate their long taproots. Additionally, they prefer a soil mixture that is well-drained and humusy—it should stay evenly moist without becoming waterlogged. Lunaria does best in soil that stays (or, through irrigation, can be kept) evenly moist.
Keep the soil your lunaria is housed in consistently moist throughout the growing season—about one inch of water (through rainfall or manual watering) a week should do. Keep in mind, the exact amount of water your plant needs can depend on your environment and its location in your landscape. Plants located in constant sunlight may be more thirsty than their shade-dwelling counterparts.
Temperature and Humidity
Lunaria plants need temperatures between 60 degrees and 70 degrees Fahrenheit to germinate and become established in the landscape. After that, as long as they're planted in the proper USDA hardiness zone, they have no special temperature or humidity requirements.
Once a year in the spring, treat your lunaria plant to a feeding with an organic or slow-release fertilizer to help encourage ample blooming.
A potential drawback in growing silver dollar plants is the ease with which they spread. Check with your county extension office before planting any to determine whether they are listed as invasive plants in your region (in which case they have the capability to crowd out native vegetation). As invasive plants go, though, lunaria plants are hardly among the worst offenders.
Harvesting and Storing
The pods can be used in dried floral arrangements, wreaths, and more. You do not have to be proficient at floral design to use them—simply insert a few dried bundles into a vase for a unique display or hang them from a hook over a window so that the sun can shine through them. Harvest the plants in the late summer after their seed pods are fully developed but before they can drop any seed.
When you're ready to harvest, cut off the plant at its base and bring it indoors. Tie your bundle of lunaria with some twine or string and suspend it upside-down in a room that boasts low humidity levels. The seed pods should be fully dried in about two to three weeks—you'll notice that the husk (which is the green, outer layer) has likely fallen off by itself, but if it doesn't, you can gently rub it off. Caring for the pods consists essentially of harvesting and drying them properly—they require virtually no maintenance beyond that.
How to Grow Lunaria From Seed
Lunaria plants have a long taproot and do not transplant well, so they're almost always propagated and grown from seed. Sow the harvested seeds outdoors in spring as soon as you can work the ground, covering them lightly with soil and water. Space seeds about 15-18 inches apart. Germination takes about 2 weeks.
While extremely easy to care for, lunaria can encounter a few pest issues that can be a nuisance. The plant is susceptible to aphids, which can be treated using an insecticidal soap or horticultural oil like neem oil.
Common Problems With Lunaria
Lunaria plants often go about sowing themselves without a care. But it can come down with a few problems. Watch for the following signs.
Gray and Black Leaves
Lunaria is susceptible to diseases like septoria leaf spot. Septoria leaf spot is a fungal disease that creates gray and black marks on the leaves of the plant. Remove parts of the infected plants and watch for signs the disease has passed.
Wilting or Yellow Leaves
Clubroot is another issue for lunaria, which can cause the leaves to wilt or yellow. If you notice these signs, prune the infected parts of the plants and observe to see if the infection resolves itself.
Are silver dollar plants succulents?
Lunaria is not the only plant with the common name of silver dollar. Lunaria is not a succulent. But the Crassula arborescens, also known as silver dollar jade or the money plant, is a succulent often used in feng shui practices to entice prosperity.
Are silver dollar plants weeds?
These plants spread enthusiastically so many gardeners consider them weeds. However, they may appear like weeds because they don't stay tidy in garden beds. They also look a little messy, like weeds. If the plants are forced to grow confined in containers, because they can grow tall and scraggly, eventually they will drop seeds outside the pot.
Is the silver dollar plant deer resistant?
No, deer love to munch on silver dollar plants. On the positive side, the plant does attract butterflies.
Lunaria annua. NC State Extension.
Lunaria annua. Missouri Botanical Garden.
Integrated Clubroot Management for Brassicas. Oregon State University Extension.