When it first appears in early Spring it looks like a mushroom is pushing through the soil. It develops into an upright shoot and looks like a mini-fir tree throughout summer. The source of the plant has been known to be as deep as 6ft (1.8 metres) so digging out the roots won’t be possible. It can be invasive if not tackled and grow to 2ft (60cm) in height.
How to Kill Marestail/Horsetail?
You could use chemicals such as weedkiller which contains glyphosate/diflufencian but this will only stop new shoots. Before applying rake over the area so you bruise the plants which will make it easier for the liquid to get inside the plant.
How to Kill Marestail/Horsetail Originally?
Use a hoe to knock off the growing tips but do this on a regular basis. Over time, 10+ years, the plants will become weaker and in time will give up and move onto a neighbouring garden.
Stop it Spreading
In late Spring spores on the plant travel on the air and form a new plant where they land. As soon as you see the mushroom tips in early Spring, start hoeing the ground on a regular basis and stop the plant from becoming established.