Mare’stail or Horsetail is a common garden weed that flourishes on damp soil. Even the RHS is prone to Horsetail as the picture taken at Harlow Carr Gardens demonstrates. I look forward to seeing how they cope!

Why it is a Problem

• The plant reproduces by spores that are readily wind dispersed but most problems come from the rhizomes.
• Rhizomes are extensive both horizontally and vertically and may reach over 5 feet deep depending on substrate.
• Rhizomes break into small parts and reproduce quickly.
• Tubers are then produced at the nodes of the rhizomes.
• You can’t dig it out, although you may weaken the plants if you remove as much root as you can then hoe when you get above 1″ shoots.

Control and Eradication

• Glyphosate weed killer will have an effect and eventually kill the plant. Apply at least 3-4 times. Crush the leaves to create an entry point.
• Ammonium Sulphamate can kill and you need a brushwood killer that incorporates it like Rootout or Deep Root
• Emerging   stems can penetrate some woven polypropylene mulches.
• Horsetail can survive periods of flooding and burning and has survived millions of years.
• Black plastic sheeting has been found to kill or suppress rhizomes in the upper layers of soil.
• Control on arable land include soil drainage, liming, deep cultivation, improvements in soil texture and persistent cutting of vegetative and spore bearing shoots has some effect.
• In grass, regular mowing over a period of years may eliminate horsetail.
• Eventually the food supply in the root is exhausted. Let it get bigger than1-2″ and food begins to be stored in the roots again, and round and round you go ad infinitum or 60 million years and still counting.

Other Resources

Most Common Weeds
Common Lawn Weeds
Uncommon Weeds
Weed control of Avens
Why war with weeds