En Español

Q. Who is Mr. Smarty Plants?

A: There are those who suspect Wildflower Center volunteers are the culpable and capable culprits. Yet, others think staff members play some, albeit small, role. You can torture us with your plant questions, but we will never reveal the Green Guru's secret identity.

Help us grow by giving to the Plant Database Fund or by becoming a member

Did you know you can access the Native Plant Information Network with your web-enabled smartphone?

Share

Ask Mr. Smarty Plants

Ask Mr. Smarty Plants is a free service provided by the staff and volunteers at the Lady Bird Johnson Wildflower Center.

Search Smarty Plants
    
 
See a list of all Smarty Plants questions

Please forgive us, but Mr. Smarty Plants has been overwhelmed by a flood of mail and must take a break for awhile to catch up. We hope to be accepting new questions again soon. Thank you!

Need help with plant identification, visit the plant identification page.

 
rate this answer
1 rating

Monday - July 27, 2009

From: Etna , NH
Region: Northeast
Topic: Invasive Plants
Title: Invasive horsetail in Etna NH
Answered by: Barbara Medford

QUESTION:

I seem to have an increasingly "healthy" supply of Equisetum in ALL of my many gardens over the years .. it is not easy to get all the rhizomes (what is?) is it possible to control it some other way? Could pH have something to do with it?

ANSWER:

There are 10 species of the genus Equisetum native to New Hampshire; we have chosen Equisetum hyemale (scouringrush horsetail) as a representative species to use as an example.  It and the rest of the  Equisetum  genus are very much wetland plants-they tolerate shade, poor drainage, occur in wet places and even standing in water. They are considered very aggressive, which you have already found out. 

We felt your question about the pH having something to do with the too-healthy growth of the horsetails was thought-provoking, but we could find no research to support that one way or the other. What we did learn was that it did best in marshy, poor drainage soils, and even standing in water. We don't know what kind of garden you have; if you have a water garden, and started the Equisetum in that water garden without confining it in pots without holes, that is no doubt the source of your problem. If it is growing in your soil, the soil must be very poorly drained, and we are wondering what other plants you have been able to grow there. 

Everyone wants a special spray that will just kill the one plant they are interested in eliminating. The Lady Bird Johnson Wildflower Center recommends neither for nor against the use of herbicides. We found two articles that dealt with elimination of this plant. The first is from University of Minnesota Extension Horsetail by Beth Jarvis.  Here is an excerpt from that article:

"Horsetails are difficult to eradicate without the use of herbicides. They favor damp, sandy or gravelly, shady places. Depending on where they're growing, improving drainage and fertility and increasing the organic material in the soil along with regular mowing or clean cultivation may make the site less hospitable. Digging the plants out, in all but the smallest sites, could be prohibitively difficult due to the depth and spread of the underground rhizomes."

Another article, from a UK newsgroup, has more herbicide information to add: Re: Horsetail Roots.

Our conclusion from all of this is that you may need to modify the environment in which your garden is growing. In other words, improved drainage, drier, richer, maybe with taller plants to shade out the Equisetum. Cut off the spore-bearing cones before they ripen and spread more spores, but with all those rhizomes under ground, it will be difficult to starve out the plant. 


Equisetum hyemale var. affine

Equisetum hyemale var. affine

Equisetum hyemale var. affine

Equisetum hyemale var. affine

 

 


 

More Invasive Plants Questions

Invasive thistles in wildflower field from Dripping Springs TX
February 17, 2014 - How to get rid of "native" thistles.. I have a large natural field that used to grow a variety of wildflowers, but in 2011 and 2012 it was taken over by thistles. I'm sure they are "native" Texas...
view the full question and answer

Wild mustard growing in disturbed ground in Montana
August 01, 2008 - I have recently planted "plugs" of wildflowers in beds throughout my yard. Because the soil was disturbed, I now not only have some beautiful wildflowers growing, but also mustard plants growing in ...
view the full question and answer

Removal of Ashe juniper trees
April 19, 2015 - I have 15 acres with scattered huge oak and elm trees with tens of thousands of Ashe Juniper (cedar) trees 2 to 10 in diameter growing within the drip zone of the hardwoods. How do I take out the c...
view the full question and answer

Something to grow under a chinaberry tree
August 29, 2008 - I have a huge Chinaberry on the west side of the house. We enjoy the shade it provides and have it limbed up pretty high, but it's located between two 2-story houses and of course drops buckets of it...
view the full question and answer

Toxicity and invasiveness of Scarlet Wisteria
May 04, 2007 - I recently purchased seeds for Scarlet Wisteria (Chinese rattlebox tree). I spoke to a neighbor about this and she warned me not to plant them as they were poisonous to hummingbirds. Can you clarify...
view the full question and answer

Support the Wildflower Center by Donating Online or Becoming a Member today.
E-NEWSLETTER | BECOME A MEMBER | DONATE NOW | MEDIA | JOBS | SITEMAP | STAFF INTRANET
© 2016 Lady Bird Johnson Wildflower Center