Field Horsetail Invasion (Equisetum)

(Question)

I can’t find anything on this weed, can’t identify it.
Looks like a small evergreen and it has rhizomes, so can’t really pull them out, they just come back.
What can I do?
It has spread almost a 1/3 of a 50’x15′ sloping perennial bed.
Would vinegar/salt/soap work here? or only a ‘all’ herbicide have to be used?
Thank you for your advice.

 

(Answer)

Thank you for your question for the Toronto Master Gardeners.

This plant  Equisetum ravens.  The common names for it are Field Horsetail and Scouring-rush, as it was used for cleaning at one time.

I would refer you to the website of the Ontario Ministry of Agriculture, Food and Rural Affairs.

The linked page discusses control of this plant. The main solution is prevention….which is not possible in your situation.

As you will read, control with the permitted herbicides does not seem to work well.

However, you can try to suppress its growth if you have patience. Cover the area with newspaper sheets or, preferably, two layers of large cardboard pieces.  Ask for the big cardboard boxes at appliance or bicycle shops.  Be sure to remove tape and staples and check that no soil is visible through any overlapping pieces. Cover this with 6 inches of mulch, not the coloured kind. In two years’ time, most weeds will have decomposed and you can then add compost.

A simpler and more beautiful possibility is to change the nature of the garden. By planting large grasses, shrubs and perennials, you will no longer see the weeds, so they will get less sunlight, and the stronger roots will actually outcompete the Horsetail for space and precious nutrients. Some suggestions: Hydrangea, Ostrich Ferns, giant Hosta, spreading and creeping evergreens, Bleeding Heart, Peony, perennial Geranium.

All the very best with your challenge!