How to Plant, Grow, and Care for Silver Dollar Plant (Lunaria Annua)

Many gardeners hate weeds. They will curse them under their breath as they drag the roots from the soil and toss them onto the compost pile with relish.

In her well-known book “To Kill a Mockingbird”, Harper Lee describes Miss Maudie’s reaction to a blade of nutgrass with sufficient illustration: “She swooped down upon it with a tin tub and subjected it to blasts from beneath with a poisonous substance she said was so powerful it’d kill us all if we didn’t stand out of the way.”

The silver dollar plant is one of those plants that gardeners tend to see as a weed. And it is indeed an invasive plant species in Virginia, Michigan, and Oregon. While it is lovely, if you live in one of these states, try planting alternatives that add the same interest to your garden.

Now, let’s discuss caring for the silver dollar plant, and how to manage and cultivate one in your garden.

What is Silver Dollar Plant?

Not all weeds are created equal. Take the Lunaria annua, also known as the money plant, the silver dollar plant, the honesty plant, and the moonwort. Because of its rather prolific nature, this plant is sometimes called a perennial.

Native Area

Lunaria annua, or silver dollar plant, is native to southeastern Europe and western Asia, especially in regions like the Balkans and Turkey. It thrives in woodland edges, clearings, and damp, shady areas, typically favoring well-drained, fertile soils.

Although not native, Lunaria annua has spread widely beyond its origin, especially in temperate regions, due to its ornamental appeal and ability to naturalize easily.

Characteristics

This annual or biennial plant is prized for its vibrant purple flowers and unique, translucent seed pods, which resemble silver coins and are often used in dried floral arrangements.

The very aspects that lead some to consider it a weed can be very useful to a gardener, especially one with children to introduce to the gardening world. They are easy to grow, forgiving if neglected (almost to a fault), and beautiful to behold. And according to lore, having a patch of it may keep your kids honest!

This flowering plant can grow 24 to 36 inches in height. In its first year, it mainly sprouts heart-shaped foliage, but in its second year, it brings fragrant lavender flowers and the famous silvery seed pods that give this plant its name.

If you’re unfamiliar with these fascinating plants, or even if you know them and usually give them wide berth for their weed association, give them a consideration as you read through this guide on silver dollar plant care.

However, note that they are invasive in Virginia, Oregon, and Michigan, and your garden may benefit from removal and replacement with a similar alternative. In the maintenance section of this piece, we’ll discuss how to keep the silver dollar plant in bounds.

Planting

In all honesty, you could probably just toss a handful of silver dollar plant seeds onto a patch of earth and end up with a lovely group of purple flowers. But if you want to be a bit more deliberate, especially if you have kids learning about gardening, follow these guidelines.

There are several options for timing when it comes to the silver dollar. Any time after the last frost in the spring or summer is recommended for the first planting. It is a biennial, meaning you probably won’t see the flowers or seedpods until the next year, so you can stagger their appearance by planting a few seeds in the fall.

Anywhere sunny or lightly shaded will do, though you might want to consider an area that’s easy to tend or contain; the honesty plant doesn’t hold back its self-sowing zeal. This is evidence of its tendency to push out other plants in some gardens.

Silver dollar is hard to transplant, so growing from seed sprinkled on the ground in fall and covered with a light amount of soil is best. Consider spacing 15 to 18 inches apart for good air circulation between grown plants. Allow the seeds to vernalize over winter, and they’ll sprout in spring.

The silver dollar will cozy up to just about any other plant, but you might be quite delighted pairing them with various tulips, forget-me-not, and Hakone grass. If you want to attract more beneficial insects and creatures to your garden, add an herb patch.

How to Grow

It’s pretty easy to provide silver dollar plant care. That alone makes it a good choice for children just getting their feet wet in gardening. Honesty plants are quite forgiving!

Light

Some gardeners have noted that it doesn’t seem to matter where the seed lands. Lunaria will grow whether it’s sunny or shady, though it may bloom better in sunnier areas.

In cooler regions, it can tolerate full sun, where it will produce more vibrant blooms. However, in warmer climates or areas with intense sunlight, it benefits from partial shade, particularly during the hottest parts of the day, to prevent leaf scorching and to maintain soil moisture. Although it can also grow in deeper shade, low light may reduce flowering and cause the plant to become leggier.

Providing a balance of light and shade generally leads to healthier growth and better flower and seed pod production.

Water

This biennial prefers to keep its toes moist, so try not to let the soil dry out between waterings. However, do not leave it standing water. In some areas, you may need to water only once a week, especially if you have made good use of mulch for continuous moisture.

Soil

This plant will tolerate just about any soil, as long as it’s well-draining. It likes a bit of fertilizer once or twice a year, but avoid fertilizing in areas where the plant is invasive. In fact, it will appreciate whatever your other plants are getting and may try to take up residence with them over time.

Temperature

Ideal temperatures for this plant range from 60 to 70°F (16-21°C). As mentioned, seeds need a period of cold stratification before sprouting in spring. It’s hardy in zones 8 to 10, and established plants can withstand frosts and high heat. However, your plants may need a little shading in hot summers and some coverage in freezes.

Fertilizer

Again, if you live in a state where Lunaria annua is classed as an invasive species, do not fertilize. This will cause the plant to grow well out of bounds, and push out other plants, many of which are native, threatened, or nearing extinction.

If you have a rich soil, you shouldn’t need to fertilize. Less fertile soils can be treated with a liquid fertilizer diluted to half strength during the growing season.

Maintenance

Pruning Lunaria annua is generally minimal, as it is a low-maintenance plant. For best results, remove spent flowers to encourage the plant to direct its energy towards developing its iconic seed pods. However, if you wish to prevent the plant from self-seeding, remove the seed pods before they fully mature.

In late fall or early spring, you can cut back any dead or damaged foliage to tidy up the plant. Avoid excessive pruning, as Lunaria annua relies on its leafy rosettes to gather energy during its first year of growth. By allowing the plant to grow naturally, you can enjoy both its blooms and decorative seed pods each season.

Harvesting

One of the most popular parts of this plant is the silvery seed pod, a favorite for dried flower arrangements and imagination games for kids. You can allow the seed pods to dry on the plant or you can snip the stems after the pods turn brown, tie a few together, and hang them to dry.

To collect the seeds, wait until they’re brown in the pod. Then rub the pod between your fingers to gently remove the outer layer. If you’d like to use the seed pods in flower arrangements, wait for them to dry out, and snip as needed. Then plop them in your favorite dried arrangement. They’ll last a long time.

Storage

Store the seeds in an air-tight container, someplace dark, cool, and dry. Mason jars, plastic containers, and small envelopes are all appropriate. The seeds should keep for a long time. Cut flowers will remain for a while as well.

Common Problems

While this plant is fairly resistant to many pests and diseases, it’s not immune. Here are a few things to watch out for.

Pests

Aphids are little sap-suckers that are usually green but can be red, black, white, or even peach-colored. They feed on the underside of the leaf and leave behind “honeydew,” which attracts ants and encourages fungal growth.

A strong blast of water can be enough to shake them off. An application of insecticidal soap may help with larger infestations.

Even better, grow neighboring plants that attract lady beetles to your garden. They think aphids are delicious and will gobble those little buggers into obscurity. A raised bed herb garden with dill and fennel would bring them in nicely.

Diseases

Septoria leaf spot is caused by a fungus and shows up as those little freckle-like holes in leaves, which eventually turn yellow and drop off. Water splashing on the leaves can spread it around. While it doesn’t usually kill, it does weaken the plant and prevent reproduction.

To reduce spread, use a drip irrigation system instead of a sprinkler. Mulch and spacing between plants allow air to circulate and keep moisture off the plants. Rotate new plants to a different area of the garden.

Clubroot looks like yellow, stunted leaves above ground, and galls shaped like clubs on the roots below ground. Rotate the plants to a different area and test the soil pH level. If it is acidic, add lime to balance it out.

White blister rust distorts plant growth and reduces vigor. Caused by a fungus-like organism, it creates white lesions on leaves that look like white powder when ruptured. Snip and destroy any affected leaves or other debris. Space out the plants for air and reduce splashing of water with mulch and drip irrigation.

Frequently Asked Question