Looking for a few simple remedies to eliminate dollarweed from your landscape?
Dollarweed is a weed that seems to appear overnight – and then spread everywhere before you realize what is happening. It pops up in flowerbeds, garden rows, walkways, and even raised beds, often forming thick mats that crowd out flowers and vegetable plants.
Although it looks harmless at first, dollarweed can quickly become invasive if left unchecked. Dollarweed, also commonly known as pennywort, gets its name from its small, round, coin-shaped leaves that grow on thin stems. While some types of dollarweed are grown intentionally in water gardens, the variety that invades lawns and garden beds is anything but welcome.
So what is the key to stopping it from growing in your beds? It all starts with understanding what dollarweed is, why it appears, and how it spreads. The good news is with a combination of better soil conditions, natural removal methods, and proper mulching, you can all but eliminate it from your landscape.
How To Eliminate Dollarweed
What Is Dollarweed?
Dollarweed is a low-growing perennial weed that spreads by both seeds and creeping underground stems called rhizomes. Once established, it forms dense clusters that can quickly take over open soil. Its leaves are round, smooth, and bright green. They often grow in clusters that resemble small lily pads.
Unlike many weeds that thrive in dry, neglected soil, dollarweed prefers moist environments. It’s most commonly found in areas where the soil stays consistently wet or compacted. This is why it often appears in flowerbeds, low spots in gardens, and raised beds with poor drainage.
Because dollarweed spreads underground, simply pulling the visible leaves is rarely enough. If even small portions of the roots or rhizomes are left behind, the plant can regenerate and return stronger than before.
The Invasive Properties Of Dollarweed
Dollarweed is on the invasive list because of how quickly it spreads and how difficult it can be to remove once established. The plant grows aggressively during warm weather. It then devours the water and nutrients that flowers and vegetables need to thrive.
One of the biggest reasons dollarweed becomes such a problem is its ability to thrive in conditions that many garden plants struggle with. Wet, compacted soil creates the perfect environment for dollarweed, allowing it to spread while other plants weaken.
Once dollarweed takes hold, it can form thick mats that block sunlight from reaching the soil surface. This makes it harder for seeds of desirable plants to germinate and grow. Over time, flowerbeds and gardens can be overtaken by dollarweed if action is not taken early.
Eliminating The Conditions Dollarweed Loves
One of the most important things to understand about dollarweed is that its presence is often a warning sign. Dollarweed does not usually appear randomly. In most cases, it indicates that the soil is staying too wet for too long.
Poor drainage is one of the most common causes. Soil that is heavy with clay or compacted from foot traffic holds water instead of allowing it to drain away. Raised beds that lack proper drainage holes or have dense soil mixes can also trap moisture, creating ideal conditions for dollarweed.
Overwatering can make the problem even worse. Frequent watering, especially in shaded areas, keeps the soil consistently damp and encourages dollarweed to spread rapidly. With that said, improving drainage and loosening the soil is the biggest key. It truly is the most effective long-term solution for eliminating dollarweed.
But if you do have dollarweed already in your beds, you also need to eliminate it first. The good news is you can do so with a few simple approaches.
4 Ways To Eliminate Dollarweed
Hand Pulling
Hand pulling is the best approach for small infestations, but you need to do it carefully. Simply snapping off the leaves will not solve the problem, as the roots and rhizomes will remain in the soil.
The best time to pull dollarweed is when the soil is slightly moist but not saturated. This makes it easier to remove the entire root system. Using a hand weeder or garden fork can help loosen the soil around the plant, allowing the roots to come out more cleanly.
Every piece of the plant should be removed and disposed of properly. Leaving pulled dollarweed on the soil surface can allow it to re-root, especially in damp conditions. Keep an eye on the soil after pulling it out. Any new growth should be pulled as soon as it appears to prevent the plant from spreading further.
Smothering With Heavy Mulch
One of the most effective natural methods for eliminating dollarweed is heavy mulching. Dollarweed needs light to grow, and a thick layer of mulch can block sunlight and prevent new growth from emerging.
Organic mulches such as shredded bark, straw, wood chips, or shredded leaves work especially well. A mulch layer of four to six inches is usually enough to smother existing plants and prevent seeds from germinating.
Before applying mulch, remove as much of the visible dollarweed as possible. This gives the mulch a better chance to fully suppress regrowth. Once down, make sure to keep the thickness to at least four inches to maintain the effectiveness.
Mulch also helps regulate soil moisture by preventing excess evaporation while still allowing water to drain properly. Over time, this creates healthier soil conditions that are less favorable to dollarweed.
Using Cardboard As A Weed Barrier
For heavily infested areas, sheet mulching can be an effective solution. This method involves placing thick layers of cardboard directly over the soil to block light and smother weeds.
After removing large dollarweed plants, lay cardboard flat over the affected area. Overlap edges to prevent gaps where light can reach the soil. Then cover the cardboard with several inches of mulch to hold it in place and improve appearance.
This method works well in flowerbeds and garden paths and can be especially helpful when starting fresh in problem areas. Over time, the cardboard breaks down and adds organic matter to the soil. See our article: How To Eliminate Flowerbed Weeds With Cardboard – And Have Beautiful Beds!
Cover Crops
Planting a fall cover crop is a simple and effective way to snuff out dollarweed in gardens and raised beds. Dollarweed loves bare, wet soil, and a cover crop quickly fills that space. As the cover crop grows, it shades the soil and blocks sunlight, making it difficult for dollarweed seeds to sprout and spread.
Cover crops also help fix one of the main causes of dollarweed – poor drainage. Plants like oats, rye, and clover loosen compacted soil with their roots, allowing excess water to drain away instead of sitting on the surface. Drier, better-drained soil creates an environment where dollarweed struggles, but garden plants thrive.
When the cover crop is cut down in spring, it leaves behind a natural mulch. This mulch continues to smother weeds while improving soil health. Over time, planting a fall cover crop can greatly reduce dollarweed and help keep it from returning.
Preventing Dollarweed From Returning
Once dollarweed is under control, prevention becomes the focus. Healthy, well-drained soil is the best defense against future infestations. Regularly adding organic matter helps maintain loose soil structure. Keeping beds mulched year-round prevents bare soil, which is an open invitation for weeds to take hold.
Inspect flowerbeds, gardens, and raised beds regularly. Catching new dollarweed plants early makes removal much easier and prevents them from spreading underground. Here is to taking the steps need to eliminate dollarweed from your garden and flowerbeds this year!
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This Is My Garden is a garden website created by gardeners, for gardeners. Jim and Mary Competti have been writing gardening, DIY and recipe articles and books and speaking for over 15 years from their 46 acre Ohio farm. They publish three articles every week, 52 weeks a year. Sign up today to follow via email, or follow along!