There is one part of my garden where no matter what I plant nothing seems to grow. I removed the mulch in this area and found some dark coloured worms which have a lighter band around their bodies. They all appear to be near the surface of the soil and have a snake-like movement. Are these normal earthworms or are they they cause of why nothing seems to really grow in this part of my garden.
Thank you for contacting the Toronto Master Gardeners. From your description it sounds as if you have invasive jumping worms (Amynthas sp.). These worms seem to have been accidentally introduced into southeastern United States through contaminated nursery stock from Japan or Korea. Over the last 15 years they have spread throughout northeastern United States.
Unlike the common earthworm (Lombricus terrestris) jumping worms are 20cm in length are dark almost grey in colour and the clitellum, the ring around their bodies is smooth and light coloured. Another disturbing factor is that these worms tend to stay on the soil surface and jump and thrash when disturbed. According to the Laidback Gardener “Check your property for earthworms using a mustard solution. (Don’t worry, it’s harmless to plants!) Mix a gallon (4 liters) of water with 1/3 cup (80 ml) of ground yellow mustard seed and pour slowly into the soil. This will drive any worms to the surface. If you discover jumping worms, avoid moving plants or soil from your yard.”
Jumping worms do not dig tunnels but remain on the soil surface feeding on the leaf litter consuming plant seeds and thus robbing the soil of it’s seed bank. Unfortunately there is no control for these disgusting invaders. If you see them you can collect them and place them in a bucket of vinegar water or place them in a bag and leave them out in the sun for 10 minutes, then throw the bag away in the trash.
The following link provides more information on these newest invaders: Cornell University: Got Worms? ,