Category: mulching garden beds

Asian Jumping Worms: Why Your Earthworms Might Be Acting Crazy

On By durhammastergardenersIn earthworm, Invasive species, jumping worm, mulch, mulching and soil chemistry, mulching garden beds, mulching leaves, mulching trees, mulching with arborist wood chips, mulching with cardboard, mulching with paper, over mulching, soil health, Uncategorized

By Marcia Kirinus NC State Extension Master GardenerSM volunteer of Durham County

Asian Jumping Worms – A Growing Threat to Soil Health

Plump juvenile Asian jumping worms in a raised bed. In late spring, early summer you will find all life stages. (Image credit: Marcia Kirinus)

If you’ve noticed unusually active worms in your garden, it could signal a serious problem. These are likely Asian jumping worms, Amynthas spp. or Metaphire spp.. Often referred to as “Crazy Worms” or “Snake Worms,” these invasive earthworms originate from Japan and Korea. They most likely arrived in North America through contaminated soil, compost, or plant material.

According to Matt Bertone of the Insect and Disease Clinic at North Carolina State University, these worms were first recorded in North Carolina in 1978. While they’ve been around for some time, they’ve recently garnered significant attention. One theory is that climate change has boosted their population and more people are gardening.

What sets Asian jumping worms apart from the gentle earthworms we know is their frantic, snake-like wriggling when disturbed—a behavior that earned them their common name.

I first heard about them from a friend and fellow master gardener. She asked if I’d seen them on my property. I had no idea what she was talking about, but I was pretty sure I hadn’t. Living in the city, I assumed this was more of a rural issue, as she lived in a damp, wooded area that seemed ideal for such pests.

One day, while visiting her home, she scooped up a handful of soil, revealing a tangle of Asian jumping worms. “They’re everywhere,” she remarked. At first glance, they appeared to be ordinary earthworms.

“How can you tell the difference?” I asked. She dropped the worms onto her cement driveway, and they immediately began thrashing like small snakes—nothing like the slow, deliberate movements of a regular earthworm. Instead of stretching and shrinking to pull themselves along, they slithered with a serpentine, S-shaped motion. I was fascinated and alarmed.

As I learned how to identify them, I discovered Asian jumping worms in every garden bed on my property—even in my enclosed raised beds suggesting that cocoons came in with the soil, mulch, plant material or on my tools which were not cleaned from using in the native soil. The revelation of these infestations helped explain some of the mysterious plant deaths and soil issues I had noticed in the past.

Why are Asian Jumping Worms Bad?

Asian jumping worms are highly adaptable and can thrive in forests, gardens, and agricultural fields. They reproduce rapidly, out competing other earthworm species. One worm can reproduce without mating through parthenogenesis and produce enough worms to infest an entire garden. Their aggressive behavior disrupts soil ecosystems and plant communities.

Unlike common earthworms, which burrow 1-4 feet below the surface, Asian jumping worms live near the topsoil and consume all organic matter in their path. Mulch, leaf litter, old decaying roots, and leaves are quickly devoured, leaving soil depleted and structurally compromised.

In their wake, they leave behind grainy, coffee-ground-like soil that lacks essential nutrients and structure. This degraded soil erodes easily, struggles to retain moisture, and makes it difficult for plants to establish roots—especially those with shallow root systems.

Asian jumping worms are an annual species; the adults die after the first freeze. However, their cocoons/eggs which are about the size of a mustard seed, survive the winter and hatch when temperatures consistently reach 50°F. The cocoons are dirt-colored and nearly impossible to spot. They can spread easily through potted plants, landscaping equipment, mulch, tire treads, your shoes or even your dog’s paws. 

How to distinguish an Asian Jumping Worm from a Common Earthworm

Asian jumping worms can be distinguished from common European earthworms (like nightcrawlers) by several features:

  • Behavior:
    • Jumping worms thrash violently and move like a snake when handled. Their tails easily break off, much like a lizard shedding its tail when grabbed.
  • Appearance:
    • The adults are the easiest to identify because they are smooth, glossy, dark brown to gray body with a prominent, white, ring-like band (clitellum or reproductive band) encircling their body. The clitellum is located closer to the head than in the common earthworm and is flush with the body, not raised. The younger worms do not have a prominent clitellum so use other distinguishing factors such as behavior, location and color to identify them.
  • Location:
    • Found in the top layer of soil or leaf litter; they do not dig deep tunnels.
  • Castings:
    • Soil in areas with jumping worms looks like loose, dry coffee grounds.
Note the visual differences from the more common earthworm above and the invasive Asian Jumping Worm below. (Image credit: Brunswick-Topsham Land Trust)

Left: Asian Jumping worm, Amynthas spp. cocoon/egg at yellow arrow, on soil surface. Note granular soil texture all around egg due to worm castings. (Image credit: Marie Johnston, courtesy of the University of Wisconsin-Madison Arboretum) Right: The light-colored clitellum, or reproductive band around the adult Jumping Worm, wraps completely around its body and is not raised as in the common earthworm. (Image credit: University of Illinois Extension, Technical Forestry Bulletin NRES-1603)

What should I do if I Find Asian Jumping Worms in my Garden?

  • Prevention is key:
    • Currently there are no great curative management options available for home gardeners with existing jumping worm infestations. Therefore, prevention is your best line of defense. Some preventative measures are:
      • Keep tools clean. Do not use tools from an infested spot in an uninfected spot without disinfecting in between.
      • Buy compost, mulch, soil from reputable places. Before you buy, ask what measures are taken to avoid Asian jumping worms.
      • When purchasing plants, buy from reputable sources and carefully inspect the root ball. If you suspect contamination, consider cleaning all soil off new plants. Purchasing bare-rooted plants is another option.
  • Inspect and Monitor:
    • Regularly check your garden and compost for signs of jumping worms. If you have them, hand pick and destroy them when you find them. Seal them in a plastic bag and throw them in the trash. Alternatively, use a bucket of soapy water to drown them in and then dispose of them. Avoid using a dry bucket, as they can easily climb out of a five gallon bucket without problem. By hand picking, you are reducing the adult population which will eventually decrease the number of egg-carrying cocoons in the landscape.
  • Predators:
    • Encourage more wildlife. According to a social media group I belong to on Asian jumping worms, many birds such as Robins, Bluejays, Grackles, Turkeys, Chickens eat the worms. Earth snakes, moles, and mice have also been reported to eat them.
  • Heat Treatment:
    • Jumping worms and their cocoons are sensitive to high temperatures. The University of Wisconsin – Madison conducted research which shows that neither worms nor cocoons can survive at 104°F or higher for over three days. Compost piles, under appropriate conditions, can reach this temperature.
  • Share Information:
    • Share your knowledge, experiences, successes, and failures with fellow gardeners. Raising awareness and sharing information can help combat the spread of these invasive worms.
  • Prevent Spread:
    • Avoid moving soil, mulch, or plants from infested areas.

We encourage you to share this post with others to help educate our community

Resources and Additional Information

Mulch Matters: Understanding Materials and Methods

On By durhammastergardenersIn arborist wood chips, Durham NC, fall gardening, garden tasks, gardening, Gardening calendar, Gardening information, ground covers, inorganic mulching material, lasagne mulching, leaf mold for mulch, mulch, mulching and soil chemistry, mulching garden beds, mulching iwth paper, mulching leaves, mulching trees, mulching with arborist wood chips, mulching with cardboard, mulching with paper, organic mulching material, over mulching, plant fungi, plant pathogen, proper mulching techniques, regenerative agriculture, renewable gardening, sheet mulching, soil, soil coverage, soil health, soil microbes, tips for effective mulching, tips for proper mulching, Uncategorized

By Eric Wiebe, NC State Extension Master GardenerSM volunteer of Durham County

(Image credit: Allie Mullin)

As the gardening season is winding down, it’s time to start thinking about your fall and winter tasks. Near the top of that list should be thinking about mulching your plantings. A tour of your yard will probably reveal thin or bare spots where last year’s mulch has either broken down or been washed or blown away (those darn leaf blowers!). You may also want to put a winter cover on areas where you had vegetables growing. Finally, you may also have new areas you are preparing as garden beds where mulch will need to go around the new plantings.

Why Mulch Matters

First, let’s review why you want to be mulching in the first place. The primary reason most people mulch is for a combination of weed suppression and moisture retention. However, there are other just as important reasons to mulch. If you are using organic materials, you have the important benefit of in-place composting and humus generation, improving the biodiversity of the ground ecosystem throughout the mulch and into the surrounding soil and plants. Depending on type and placement, mulch can also help with erosion control and compaction. In addition to absorbing and holding moisture from rainfall, it can also minimize water splash from the underlying soil onto plants–potentially limiting the spread of harmful soil-borne fungi, such as blight. Finally, there may be good aesthetic reasons to mulch to create sharp delineations in color and texture in the landscape.

Types of Mulching Materials

What kinds of materials can you mulch with? Broadly speaking, mulches are grouped into organic and non-organic types. Included in organic materials are natural products, primarily from trees, that have been processed but will readily decompose–this includes cardboard, newspaper, and other paper products. 

Inorganic Mulch

The most common non-organic materials are landscape fabrics made from plastic–either sheet or woven–and various types of stone. These are often used together, as the landscape fabric can be placed under the stone to help suppress weeds and keep the stone from migrating into the soil. Plastic sheet, with or without perforations, is also used in fruit and vegetable production, often applied with specialized machinery. The rest of the blog post will focus on the more popular and beneficial organic mulches used by home gardeners.

Organic Mulch

While shredded hardwood comes to mind when thinking about mulch, other organic materials like leaves are great sources for mulching material. As they decompose, leaves improve soil health by providing nutrients and improving both water retention and percolation. (Left) Newly-raked leaves ready to be spread across the garden. (Right) Leaf mulch after a year of decomposing. (Image credit: Eric Wiebe)

Organic materials can be found from a variety of sources. The best and most convenient materials are those found right in your yard. This includes leaves, new or partially decomposed; grass clippings, compost, and plant and tree trimmings. There is the argument to be made that the best mulch sources are the most local, as they represent the local ecosystem and can best support the macro-/microbiome already in your yard. 

(Left to right) Arborist chip drop ready to be spread and a close-up of this type of mulching material. (Image credit: Eric Wiebe)

If you don’t have enough organic sources of mulch within your own yard, consider arborist wood chips. These are the product of local tree services as they cut down and chip tree limbs and can be acquired for free through a national service, ChipDrop (https://getchipdrop.com/). This product is still relatively local, representing tree species from your area and, for most of the year, contains a mixture of bark, wood, and leaves.

Research has shown that wood chips perform well with regards to moisture retention, temperature moderation, and weed control. While you can buy shredded (often from grinding whole trees), bark, and sawdust mulches from garden centers, many of these products are imported from other areas, bagged in plastic, or dyed. All of these factors both increase your cost and reduce their sustainability. In contrast, the biochemical and physical diversity of arborist chips resists compaction and creates a more diverse habitat for insects and microorganisms. Over time, the bark, wood chips and leaf matter will decompose, adding nutrients to the soil.

Paper products like newspaper and cardboard have long been used for sheet mulching/lasagne gardening techniques. Here a homeowner is using cardboard shipping boxes stripped of labels and tape as a base layer to be covered by other natural mulching materials. (Image credit: Melinda Heigel)

There are many, many other types of organic mulches that can be used. Pine straw is popular in NC and can be very local if you have a lot of pine trees on your property. While compost can also be used as mulch, its cost typically prohibits its use over a large area. Finally, paper products in the form of cardboard, newspaper, and brown paper have long been used as a form of sheet mulching. Note that you typically have to cover these materials with a somewhat dense mulch (e.g., partially decomposed leaves) in order to hold it in place. While there has been some social media controversy over the use of cardboard, it is still generally believed to be a quality mulch material when applied properly. Note that you should carefully remove non-decomposable elements such as tape and staples, and avoid glossy, non-brown cardboard as they may contain unwanted inks and plastics. While grass clippings can be used as a mulch, it tends to decompose quickly, not drain well when wet or blow away when dry. They may also contain excessive fertilizer or herbicides. Instead, consider mulching it in place in the lawn.

Tips for Effective Mulching

There are best practices to consider when using any mulch, and some considerations for specific types of mulches. First, to the best of your ability, plan how much area you have to cover and what volume of mulch you need. As a rule of thumb, you will need 6 cubic yards of mulch to cover 1,000 sq ft at 2″ deep–you generally will want to keep your mulch 1-3″ thick. However, this thickness will be driven in part by the density of the mulch; how well it retains moisture and allows oxygen to pass through it. Lighter mulch material such as pine straw or newly raked up leaves can often be deeper, while wood chips should be around 2-3.” If mulch is piled too deep, is too fine, or retains too much water, air cannot penetrate the mulch layer and the mulch and underlying soil can be depleted of oxygen. Mulch decomposing in low oxygen (anaerobic) conditions will sour, or ferment, producing methanol and acetic acid, which can be toxic to plants.

(Left to right) A properly-mulched tree has a few inches of mulch that extend to the edge of the drip line (or area that mirrors the tree’s crown). The root flare is visible at the base of the tree, as mulch isn’t in direct contact with the trunk. By contrast, the tree on the right is an example of all-to-familiar over mulching. Known as “volcano mulching,” mounding mulch around the trunk is harmful to your tree, leading to its decline and possible death. (Image credit: Penn State Extension; Eric Wiebe)

For all plants and trees, make sure to apply mulch all the way out to the drip line as you want to provide weed suppression, moisture retention, and soil benefits to all of the roots of the plant. Trees are another case of the dangers of over or improper mulching. Mulch should not come in contact with the bark of the tree as it promotes the kind of dark, moist environments that allow harmful fungi to enter the tree through the bark. Think donuts rather than volcanoes when you mulch your trees.

Impact of Mulch on Soil Chemistry

Using pine straw mulch as an acidifier on blueberries. (Image credit: Eric Wiebe)

Mulches can influence soil chemistry. While most of the time, this is happening in a good way, you need to understand the properties of the mulch you are using. Pine straw and pine bark, for example, has a naturally low pH. While this may be a problem on some plants, you can use it to your advantage with acid-loving plants such as azaleas or blueberries. Organic mulches with a high carbon-to-nitrogen ratio, like sawdust, hardwood bark, or wheat straw, may induce a short-term nitrogen deficiency as it breaks down. If plants in the mulched area become chlorotic and growth slows, consider applying one to two pounds of nitrogen per 1,000 sq ft to compensate. Almost all mulches will have a very localized nitrogen deficiency at the boundary between the soil and mulch. However, this is good as it inhibits weed growth.

Many of the basics and a few of the nuances about mulching have been covered here. As with most aspects of gardening, you can, if you want, continue to go down the rabbit hole of the science of mulching. The resources below will get you started!

Resources and Additional Information

General guidelines on mulching trees and shrubs: https://extension.umd.edu/resource/mulching-trees-and-shrubs/

Mulching garden beds:

https://carteret.ces.ncsu.edu/2021/08/mulching-your-garden-beds

https://yardandgarden.extension.iastate.edu/how-to/using-mulch-garden

Benefits of using arborist wood chips: https://pubs.extension.wsu.edu/using-arborist-wood-chips-as-a-landscape-mulch-home-garden-series

Tips for mulching in the spring: https://ext.vt.edu/lawngarden/turfandgardentips/tips/Springtime_mulch.html

Comprehensive guide to mulching materials: https://extension.unh.edu/sites/default/files/migrated_unmanaged_files/Resource007193_Rep10385.pdf

Sheet mulching/lasagne gardening gardening with paper products: https://extension.oregonstate.edu/gardening/soil-compost/sheet-mulching-aka-lasagna-composting-builds-soil-saves-time

https://extensiongardener.ces.ncsu.edu/2020/01/sheet-mulching-2020-winter-piedmont-news/

Problems with over mulching: https://pender.ces.ncsu.edu/2020/10/can-too-much-mulch-killl-plants/

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