Honesty plant

Behind the virtue there is a plant: Lunaria annua, a European member of the mustard family. Fourteen common names follow it, among them money plant, silver dollar, moneywort, moonwort and Judas' penny. Every coin name points at the same object, the flat silvery discs that stand on the stems after the seeds have dropped. Those discs are what people grow it for.

The honesty plant is an upright biennial in the mustard and cabbage family, European by origin and now grown across the temperate world. It stands 2 to 3 feet tall and 1 to 2 feet wide on green or reddish stems. The leaves are coarse, heart shaped and toothed, 3 to 6 inches long and 1 to 3 inches wide. Purple flowers open in leafy racemes of four petals, mostly through April and May, with a white form grown as Lunaria annua var. alba. They are fragrant, which is half the reason anyone grows the genus. Honesty is also a brassica, so it can take the same club root that distorts cabbage roots and stunts the top growth. That matters if it shares ground with vegetables.

What follows the flowers is the reason most people plant it. Each fruit is a flat silicle, oblong-elliptic to nearly round, with a satiny, paper-white septum inside. As it ripens the two outer walls fall away with the seeds and leave that partition standing on the stem. The disc is translucent, 1 to 3 inches across, and it can hold on through winter depending on the weather.

The common names cause real trouble. Money plant, moneywort, penny flower, silver dollar and money-in-both-pockets all describe this one species, and two of them belong to other plants in the toxic-plant list a worried owner is most likely to open. The ASPCA files Silver Dollar under Crassula arborescens, an unrelated succulent that is toxic to dogs and cats, and Money Plant under Pachira aquatica, the money tree. Honesty itself appears under none of its own names: the alphabet runs from Hollyhock straight to Honey Locust, with no Lunaria, moneywort, moonwort, penny flower or dollar plant anywhere in it.

The species name says annua and the plant does not live by it. Sown in spring, honesty makes only foliage the first year, then flowers, fruits and dies in the second. That one fact answers most of what gardeners ask about it. A first-year plant sitting as a rosette with no flower stem has not failed and needs nothing done to it, since it is running the same two-year pattern as foxglove. What hides the habit is the patch. Honesty self-seeds so freely that a patch left alone will never disappear, so there are flowering plants in the same ground most years while no single plant lives past its second summer. Gardeners describe that as the plant coming back annually.

Two labels on seed packets add to the confusion. Lunaria biennis is an older name for the same species, recorded alongside Lunaria inodora, so a packet using it holds nothing different from one that says Lunaria annua. The other label is a plain error: one seed company sells honesty as a perennial while its own product text calls it biennial and explains that it self sows and returns year after year. Honesty is a biennial. The perennial in the genus is a separate species, Lunaria rediviva, which is larger, carries smaller and more fragrant flowers, has more sharply toothed leaves and sets elliptical fruit.

Dried pods for a particular winter are decided by a sowing made in an earlier growing season. The British calendar runs like this: sow in June, plant out from September through November, expect flowers in April and May, and collect seed from August through October. In American gardens the equivalent is a spring or early summer sowing that gives the rosette a full season to build before winter. The discs are not silver on the day the fruit forms either, because the outer covers have to be shed or rubbed away before the translucent center shows. Growing honesty for a wreath therefore runs across two seasons. Anyone who sows in spring and goes looking for pods that fall is a season early.

Sow honesty where it is meant to grow. Seed goes outdoors in spring as soon as the ground can be worked, or after the last frost in groups of three or four seeds, and germination spreads over 14 to 28 days. Space the plants 12 to 18 inches apart to allow for their size at maturity. Sowing in place in early summer is the recommended method of propagation, and fall sowing works as well. In the warmest gardens the clock is shorter: seed sown in fall in zones 8 to 10 flowers the following spring.

Transplanting is the job to settle before you buy plugs. Honesty makes a large taproot, so it goes out young or not at all, and larger plants establish poorly. Even a young one is difficult to move, and scattering seed where the plants are wanted avoids the question. The two positions disagree about whether a young plant travels safely, and agree that the older the plant, the worse the move. If you do start under cover, sow into pots or a seed tray in early summer. Move the seedlings into larger pots once they are big enough to handle, then set them in their final positions in fall.

Honesty takes either full sun or partial shade. Its light range runs from six or more hours of direct sun down to partial shade of two to six hours a day, and half shade suits it best of all. It belongs in borders, open woodland, shade gardens, naturalized corners and the cutting bed, the same half-lit ground where most other flowers that grow in shade earn their place.

Soil should be moist, well drained and high in organic matter, on any pH from acid below 6.0 through neutral up to 8.0. Water needs are medium. Size follows the soil. Plants grow tallest in rich, moist, free-draining ground, stay smaller and carry fewer pods in poor soil, and come through winter best where the ground drains freely and never sits saturated.

Honesty is a cool-climate plant that takes hard frost without help. Zones 5 to 9 is the figure given most often, cut-flower growers overwinter it down to zone 4, and hardiness data elsewhere runs from zone 4a through 8b. Take the coldest of those as the working limit, and expect the plant to get less predictable as winters soften. In Britain it comes through minus 20 to minus 15 degrees Celsius. The warm end of the range works differently: in zones 8 to 10, seed sown in fall flowers the following spring, which is a sowing instruction for mild winters and says nothing about summer heat.

Honesty spreads on its own, and no state has put it on a noxious weed list. It is introduced in the United States and not native to North America. It grows wild in 21 states, from California and Washington across to Connecticut and Tennessee, and has naturalized in wooded parts of the east. The ground it takes is disturbed and human-maintained: fields, roadsides, banks and waste places. It seeds itself hard enough that a patch left alone will never disappear. Most gardeners who call honesty invasive mean exactly that, and none of it is a legal designation.

Washington, Oregon, Connecticut and Rhode Island all publish lists, and honesty is on none of them. Washington's noxious weed list, the one that sets what landowners can be required to control, runs from Linaria vulgaris straight to Myriophyllum spicatum. Oregon designates no weed called Lunaria, honesty or money plant. Connecticut's statutory list, which bans the import, sale, cultivation and distribution of what it names, goes from Lepidium through Lonicera to Lychnis. Rhode Island names honesty nowhere on its list of invasive and weedy plants, and that list carries no regulatory force in any case.

Databases are looser than statutes. Go Botany tags Connecticut as present, invasive and prohibited while warning that status definitions vary from state to state, and the Connecticut statute does not carry the plant at all. NC State Extension reports the species as invasive in some areas of the country and advises considering a native alternative. That advice stands on its own footing. Gardeners split by region. The complaint out of Seattle is that honesty displaces natives in local greenbelts and should be pulled wherever it is found, and King County answered that the patches there looked small. Across 32 grower comments the split runs 25 positive, 6 neutral and one negative, and the negative is that Pacific Northwest complaint.

Cutting the pods is also how the plant is kept in bounds. The seed rides inside the same flat fruits people harvest, and a ripe one sheds its outer covers and its seeds together. Stems taken indoors while the green is just going carry that seed out of the bed with them. Where the pods are left standing, deadhead before they ripen and the volunteers stay down. Seedlings that do appear lift by hand without much argument, because each sits on a single taproot and comes up whole, easiest as a first-year clump or at any point before the second-year pods ripen. None of that touches the seed already lying in the soil. A patch keeps producing after the parent plants are gone, and it takes a few seasons of pulling to run out. Anyone who likes the effect can do nothing at all and let it run, the way a corner of forget-me-nots refills itself.

Cut the stems as the green goes out of the fruit. That is the whole timing signal: take the stems out of the garden just as the green fruit color disappears, then hang them upside down indoors to dry. The perennial species gets a slightly earlier signal, cut just before its green begins to fade. Seed collectors work the other way and leave the pods to dry on the plant before breaking them open. The plant allows it: the fruits stand where they grew into winter, and the weather decides how long they hold. The choice between the two is a choice about exposure. Stems cut early finish in still indoor air, and stems left standing take whatever the fall gives them.

Husking is the part nobody photographs. Put the whole dry branch upside down into a paper shopping bag and shake it firmly. That peels most of the discs clean, the covers that hold on rub away between thumb and forefinger, and the seeds and shed covers gather in the bottom of the bag. The bag holds the next sowing at the same time, because the seed leaves the fruit as the disc is exposed. Prepared with that much care, dry branches keep for years in an arrangement, and dried-flower work is one of the garden uses honesty is grown for.

Seed listings sell fewer distinct plants than they appear to. The species carries purple flowers, the named selections are white, variegated or dark leaved, and the last entry is a separate species.

The species form

Purple

Purple flowers, April to May
2 to 3 ft tall, 1 to 2 ft wide

var. alba

White

White flowers on the species form

var. albiflora

Award of Garden Merit

Large white flowers, and a British Award of Garden Merit

'Alba Variegata'

Variegated

White flowered over variegated leaves, and an award winner too

'Chedglow'

Dark leaves

Chocolate leaves under lilac flowers
Reaches about 1 meter

Lunaria rediviva

Separate species

Perennial honesty, pale lilac in May and June, zones 5 to 8
2 to 3 ft tall, 9 to 18 inches wide

Before the fruit forms, honesty passes for dame's rocket often enough to be worth a second look. The fruit settles it.

Honesty in fruit

Flat, round, silver dollar pods standing out from the stem

Dame's rocket

Long, slender, cylindrical pods where honesty makes flat discs

Honesty in its first year

A leafy clump with no flowering stem, which is the normal first season

Honesty works as an early nectar plant and as a host for a caterpillar. Its flowers feed butterflies and long-tongued bees while they are open in April and May. Which caterpillar it hosts depends on the country. NC State Extension names the cabbage white butterfly as the larval host in America, and British growing advice names the orange-tip. Neither speaks for the other's fauna, so both hold where they were written. Rabbit and deer resistance is claimed in the seed trade and nowhere else.

Nothing published answers either half of this question. The claim that honesty is edible circulates among foragers, unanswered. No botanical, horticultural or toxicological source stands behind it, and nothing stands against it. That leaves no basis for eating any part of the plant. The pet question ends in the same place. The toxic-plant list that files Silver Dollar under a succulent carries no entry for honesty under any of its own names. There is no published rating in either direction, so caution is the only safe reading. One hazard is documented and it has nothing to do with eating: the pollen may cause an allergic reaction.

The name comes from the pods. Honesty was recorded in the sixteenth century for the translucence of the seed partitions, which show what they hold. The coin names run darker. In Denmark and in Dutch-speaking countries the plant is judaspenge and judaspenning, the coins of Judas, after the thirty pieces of silver paid for the betrayal of Christ. The Victorian language of flowers gave the plant fascination or sentiment, other systems gave it honesty and money, and folk practice used the pods in protection and prosperity spells because they look like coins. Older still is the earliest surviving recipe for a flying ointment, written down around 1440, which lists Lunaria as the ingredient answering astrologically to the moon, to be picked on a Monday.

1. The genus holds a third species that nobody grows. Lunaria telekiana is a rare plant of the mountains of Albania, Montenegro and Serbia.
2. The perennial honesty has its own sowing window. Its seed can go in during fall or spring, and the plants self-seed where conditions suit them.

Related Guides & Flowers

Hollyhock

The other cottage spire that holds its ground by seeding itself, on the same patient timetable.

Sweet alyssum

A low scented edger that comes back from its own seed, for the front of the same half-shaded bed.

White flowers

Where the white honesty forms sit among the rest, if the color scheme is what you are planting for.

Types of flowers

The full catalog of flowers on the site, sorted by kind, when you are choosing what goes in beside it.