Horsetail or Mare’s Tail?

Is it Mare’s Tail or is it Horsetail? I’ve always thought they were the same plant. How wrong was I?

Mare’s Tail – Hippuris vulgaris, although similar in appearance, is, I believe, a water/pond growing plant. It will produce flowers.

Horsetail – Equisetum spp., approx 30 varieties. The one which grows in our allotments is probably Field Horsetail (Equisetum arvense), although it may be others. It likes damp/wet/marshy ground, but can establish in any heavy dampish ground. It reproduces by spores produced by short brown shoots early in the season. What we normally see is the familiar (Christmas tree shaped) green shoots.

They are notoriously difficult to eradicate, once established. Any small piece of their spindly black root will re-establish as a plant, and their roots can, apparently, go as deep as 8 feet.

If you are unlucky enough to import pieces of root in a topsoil or compost dressing – weed it out every time it appears above soil. This should prevent it becoming established.

However, some useful news, from a lecturer in a horticultural college in the North of England, very keen on organic growing:

Soak the green shoots of horsetail in water – long enough for it to rot down and release the silica in the plants ( how long he didn’t exactly say). This is an excellent deterrent for blight – potato or tomato (apparently the silica acts as a barrier to blight on the leaves).

As Copper Sulphate (Bordeaux Mixture) is under threat from the government as a treatment for blight – copper being one of the heavy metal poisons – not as toxic as lead, but nonetheless! Up ‘til now Bordeaux Mixture has, I believe, been acceptable to organic growers. Perhaps this is a new, more organic method worth a try.

– Marjorie McCartney