Annual Honesty (Lunaria annua)

Annual Honesty, Dollar Plant, Honesty, Lunaria, Money Plant, Moneywort, Moonwort, Silver Dollar

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 seed pods emerge the following year.

I. Appearance and Characteristics 

Lunaria annua, commonly called honesty or annual honesty, is a species of flowering plant in the cabbage and mustard family Brassicaceae. It is native to southern Europe, and cultivated throughout the temperate world.

It is an annual or biennial growing to 90 cm (35 in) tall by 30 cm (12 in) broad, with large, coarse, pointed oval leaves with marked serrations. The leaves are hairy, the lower ones long-stalked, the upper ones stalkless. In spring and summer it bears terminal racemes of white or violet flowers, followed by showy, green through light brown, translucent, disc-shaped siliques (not true botanical seed pods), sometimes called moonpennies. When a silique is ripe and dry, a valve on each of its sides readily falls off, and its seeds fall off a central membrane which has a silvery sheen, 3–8 cm (1–3 in) in diameter; the membrane can persist on a plant throughout a winter depending on the weather. These siliques are much used in dry floral arrangements.

This plant is easy to grow from seed and tends to naturalize. It is usually grown as a biennial, being sown one year to flower the next. It is suitable for cultivation in a shady or dappled area, or in a wildflower garden, and the flowers and dried siliques are often seen in flower arrangements. Numerous varieties and cultivars are available, of which the white-flowered L. annua var. albiflora and the variegated white L. annua var. albiflora ‘Alba Variegata’ have won the Royal Horticultural Society’s Award of Garden Merit.

II. How to Grow and Care

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.

Sunlight

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.

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.

Watering

Annual honesty has fairly low water needs and in times of regular rainfall, it probably won’t need to be watered at all. But if rainfall drops below a benchmark figure of 1 in per week then it is a good idea to water it. The best way to know if it is ready for water is to check if the first 1 inch of topsoil is dry. If so, then water the plant.

Soil

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.

Fertilizing

A little extra fertilization helps annual honesty, but it doesn’t need much. the best system is to apply a balanced slow-release fertilizer, or an organic fertilizer such as mulch, to the surrounding soil. Do this just once a year in spring, at the beginning of the annual growing season.

Pruning

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.

Propagation

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.

Pests and Diseases

Common Pests

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.

III. Uses and Benefits 

Annual honesty is a perennial herb that is often grown ornamentally for its showy purple flowers. The plant is easy to grow and is shade-tolerant, it thrives in shady borders and woodland gardens. The flowers attract bees and butterflies to the garden when they bloom in spring. Annual honesty pairs well with tulips and daffodils.

In the language of flowers, the plant represents honesty, money, and sincerity. In witchcraft, the honesty plant is considered protective, being thought to keep away monsters. The plant is also used in spells for prosperity, the flat pods (when ripe and silvery) resembling coins and therefore being seen as symbolizing promises of wealth. In the earliest surviving recipe for a flying ointment (recorded by Bavarian physician Johannes Hartlieb circa 1440), Lunaria is included as the herbal ingredient corresponding astrologically to the moon and therefore to be picked on the lunar day of Monday.

IV. Harvesting and Storage

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.

Annual Honesty (Lunaria annua) Details

Common name Annual Honesty, Dollar Plant, Honesty, Lunaria, Money Plant, Moneywort, Moonwort, Silver Dollar
Botanical name Lunaria annua
Plant type Herbaceous Perennial
Hardiness zone 5a, 5b, 6a, 6b, 7a, 7b, 8a, 8b, 9a, 9b
Growth rate Fast
Height 2 ft. 0 in. - 3 ft. 0 in.
Width 2 ft. 0 in. - 3 ft. 0 in.
Sunlight Full sun (6 or more hours of direct sunlight a day)
Soil condition High Organic Matter
Flower color Pink
Leaf color Green