Money plant (Lunaria annua)

Synonyms: Lunaria biennis

Common Names: Honesty, annual honesty, silver dollar, dollar plant, moonwort, moneywort, penny flower

Description:

Money plant (Lunaria annua), also called honesty, is a biennial in the mustard family, native to central and southern Europe and western Asia [1][3]. It is widely grown as an ornamental for its purple spring flowers and its flat, round, papery, silver-dollar seedpods, which are prized for dried arrangements [2]. MISIN tracks it because it escapes gardens and self-seeds prolifically into woodland edges, roadsides, and shady disturbed ground, where it naturalizes and forms patches [2][3].

Habit:

Money plant lives for two years. In its first year it forms a low clump of heart-shaped, coarsely toothed, hairy leaves; in its second year it sends up an erect, hairy, lightly branched stalk 2 to 3.5 feet (0.3 to 1.1 m) tall, tipped with loose clusters of four-petaled flowers in pink, purple, or white [1][2][3]. But the sure giveaway comes after bloom: the seedpods are flat, round, and papery, about the size of a silver dollar, and they ripen from green to tan and finally to a translucent, silvery "coin" ? like a little full moon you can see through [1][2].

It is easiest to spot in late spring when the fragrant purple flowers are open, and again in late summer and fall ? even into winter ? when the pale, translucent round seedpods stand out on the dead stalks [1][2].

At-a-glance cues:

1. Flat, round, papery seedpods the size of a silver dollar that turn translucent and silvery [1][2]
2. Four-petaled pink-to-purple (sometimes white) flowers in loose clusters in late spring [1][3]
3. Heart-shaped, coarsely toothed, hairy leaves on an erect, hairy stalk 2 to 3.5 feet tall [1][3]
4. A two-year plant: a low leafy clump the first year, a flowering stalk the second [1][2]

Leaves:

1. Arrangement: alternate along the stem, the lowest leaves sometimes opposite [3]
2. Shape: heart-shaped to broadly oval, with a pointed tip [1][2]
3. Margin: coarsely toothed [1][2]
4. Surface: hairy, medium green [2][3]
5. Stalk: the lower leaves are stalked [3]
6. Size: about 1.5 to 6 inches (4 to 18 cm) long [1][3]

Stems:

1. Habit: an erect, herbaceous (non-woody) biennial, 2 to 3.5 feet (0.3 to 1.1 m) tall [1][2]
2. Branching: little-branched and hairy [1]
3. Root: a single taproot [3]
4. Life cycle: a low leafy clump the first year; a flowering stalk the second year, then the plant dies [1][2]

Flowers:

1. Color: pink to purple or lavender, sometimes white [1][2]
2. Form: four petals, about 1/2 to 3/4 inch across, fragrant [1][3]
3. Arrangement: in loose, upright clusters (racemes) at the top of the stalk, about 10 to 20 flowers each [3]
4. Bloom time: late spring into early summer [2][3]
5. Sex: flowers are perfect ? each has both male and female parts [1]

Fruit and seeds:

1. Fruit: a flat, round (orbicular), papery seedpod, about 1 to 2 inches (2.5 to 5 cm) across [2][3]
2. Color: green ripening to tan, then aging to a translucent, silvery "coin" with a pearly-white inner membrane [1][2]
3. Seeds: a few flat, disk-shaped brown seeds held inside each pod [3]
4. Dispersal: seeds spill as the pods break down; they also travel in dumped garden waste and soil, and when people cut the pods for dried arrangements [1][2]
5. Spread: reproduces by seed only, and self-seeds heavily [2]

Habitat:

Money plant grows on disturbed, part-shaded ground ? gardens and their edges, woodland borders, roadsides, fields, hedgerows, and shady waste areas [1][3]. It is native to central and southern Europe and western Asia and was brought to North America as a garden ornamental [1][3].

It does best on moist, rich soils in full sun to part shade, and it readily jumps the garden fence, naturalizing across much of the United States and southern Canada [2][3]. It is listed as invasive in some states [2][3].

Reproduction:

Money plant spreads only by seed, but it is a heavy self-seeder ? gardeners often say that once it is established, it never really goes away [2]. Its papery pods break open and drop flat, disk-shaped seeds around the parent plant, and those seeds sprout readily in nearby beds, lawn edges, and shady ground [2]. It also moves to new places in dumped garden waste and soil, and ? because the pretty pods are cut for dried flower arrangements ? people sometimes carry the seeds around and drop them [1][2].

The plant lives two years: seeds sprout and grow a leafy clump the first year, then flower, set seed, and die the second [1][2]. This makes control straightforward in principle ? pull the plants before the second-year pods ripen and drop seed ? but a patch keeps coming back from the seeds already in the soil, so it takes a few seasons of removing plants before they seed [2].

Impact and Damage:

Money plant is not a health hazard, and for most homeowners it is simply a pretty plant that spreads more than they bargained for ? self-seeding out of the garden into lawn edges, beds, and nearby shady ground [2]. The larger concern is that it escapes cultivation and naturalizes: it has spread across much of the United States and southern Canada and is listed as invasive in some states [2][3].

Where it takes hold in woodland edges and shady disturbed ground, it can form patches that fill in space other plants would use [1][3]. Its documented ecological impact is relatively limited, so it is best treated as a garden escape to watch and keep out of natural areas, removing patches while they are small [2][3]. No dollar figure for its damage in North America has been established.

Similar species:

No look-alikes are currently tracked for money plant in the MISIN region, so this comparison comes from published sources. Money plant's flat, round, papery seedpods are unmistakable, so the main confusion is with another purple-flowered garden escape before the pods form.

Dame's rocket (Hesperis matronalis) is an introduced invasive mustard with very similar showy clusters of four-petaled pink, purple, or white flowers in spring, so the two are easily mixed up while in bloom [3][4]. The sure difference is the seedpod: dame's rocket makes long, slender, cylindrical pods ? up to about 5 inches (14 cm) long but only about 1/16 inch (2 mm) wide ? while money plant makes the flat, round, silver-dollar pods; dame's rocket also has narrower, lance-shaped leaves [3][4].

Monitoring and rapid response:

Signs to watch for:

1. Purple (or white) four-petaled flower clusters in late spring, on erect, hairy stalks 2 to 3.5 feet tall, in gardens, shady edges, and roadsides [1][3].
2. Flat, round, papery, translucent silver-dollar seedpods later in the season ? the surest sign ? standing on the dead stalks into winter [1][2].

What you can do:

1. Pull or dig the plants by hand ? they have a single taproot and come up fairly easily, especially as first-year clumps or before the second-year pods ripen [2][3]. Aim to remove them before the pods turn papery and drop seed.
2. Cut and bag the seedpods rather than leaving them or composting them, and don't scatter cut pods used for dried arrangements ? the pods are full of seed [1][2].
3. Pull returning seedlings for a few years, since seeds already in the soil keep sprouting [2].
4. Don't plant it where it can spread into nearby woods or natural areas; choose a non-spreading or native plant instead [3].
5. For crews and land managers: target small, outlying patches at woodland edges first, remove plants before they seed, and revisit for several years to exhaust the seeds in the soil [2][3].

When to call a professional:

1. Large, well-established patches in natural areas or on difficult terrain where repeated hand-pulling is impractical [2][3].
2. For chemical control options, contact a licensed applicator or your local cooperative extension office.

Report sightings to MISIN. Help track this species' spread by submitting observations through the MISIN web site or the MISIN mobile app (Android, iOS, Windows, and macOS). Photos at multiple angles paired with a precise GPS location are the most valuable data for confirming new occurrences and triggering rapid-response review.

Credits:

1. North Carolina Extension Gardener Plant Toolbox. Lunaria annua. plants.ces.ncsu.edu
2. Missouri Botanical Garden Plant Finder. Lunaria annua. missouribotanicalgarden.org
3. Native Plant Trust, Go Botany. Lunaria annua (annual honesty). gobotany.nativeplanttrust.org
4. Native Plant Trust, Go Botany. Hesperis matronalis (dame's rocket). gobotany.nativeplanttrust.org

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