Cynoglossum officinale  (Hound’s Tongue)

In case you are not familiar with hound's tongue, please get familiar with it and watch for large populations. This plant is known to be one of the most problematic weeds in the great plains states, but has generally has not been considered a major problem in the Midwest (it had less than ten persons reporting it on the IPAW working list). If you find this plant, it would be useful if you submitted a report (PDF form attached) so we can assess how troublesome this plant may be(come). If possible, please send a vouchers specimen or digital photo in with your report. If submitting a voucher or photo, send in to the UW Madison Herbarium (address on form). If just sending in the reporting form or a less detailed note, please send it to David Eagan, ER-6, DNR, Box 7921, Madison WI, 53707 or eagand@dnr.state.wi.us.

This report is from Whitefish Dunes State Park in Door Co.  

We are also having issues with the Dames Rocket.  Again trying hard. 

This report is from Michigan, but in similar habitats to what is found along Wisconsin's Lake Michigan counties.

Re: Cynoglossum officinale  (Hound's Tongue) - a species I have found to be highly invasive on our Niagara Escarpment property in Garden, Michigan

This "introduced" plant is a biennial that has become extremely invasive on our Garden, MI property.  Last year I pulled hundreds of flowering second-year plants from one dense stand (an acre or two) and several small colonies, in areas ranging from cobble lakeshore, to a wetland area that has been flooded in the past, and a rich upland forest that also contains large areas of blue cohosh, dutchmen's britches, and jack in the pulpit.

This year the original large stand again was densely populated with flowering plants.  I pulled all the flowering plants I could see.  At about 100 an hour by my rough calculation, I have no doubt that I pulled thousands of plants.  In addition, I found other, smaller stands from which I cleared the flowering plants.  In one case, the site was right on the edge of a small bit of the escarpment, especially notable for its richness: small ferns, blue cohosh, mossy rocks.  The Hound's Tongue would be growing exactly in the midst of a stand of these other plants, and seemed to have very tenuous connections with the soil - almost as if the plant could grow without any real anchor.  When I pulled one growing from moss on a large rock; a sheet of moss came away with it.

Unfortunately, between the first day I pulled (June 7) and the last day (June 14), the seeds had become quite fully formed into bright green 'nutlets'.  (Later they are brown "burrs".)  Not knowing at what stage the seeds become viable, and afraid that pulling the plants and letting them lie on the ground wouldn't prevent the seeds from germinating, I started to "break" the stems (to prevent continued nourishment from the tap root system) and heaped the plants as much as possible.  I can only hope that the seeds are not yet viable and do not continue to develop.   

The seeds are covered with hooked hairs; it is easy to see how they are distributed on animals' fur or our clothing and boots.  That accounts for finding them in widespread places.  But further, I noticed that as the seeds were forming, several plants were bent over with the flower/seed heads lying on the ground.  That accounts for the extremely dense stands.  If the seeds aren't carried away by man or beast, they are capable of germinating right next to each other.  The plants completely carpet the ground.

I have done all I can for this year as far as trying to pull the flowering plants.  It may be that I was too late and many of the seeds will germinate where they lay on the ground or on piles.  I will keep an eye on the sites, and also pull as many non-flowering plants as I can.  With a few exceptions, all pull up quite easily.

We have owned this property for 17 years, and only in the last few years did I start to see this plant as a problem.  That raises the question, how many years did it take for Cynoglossum officinale to become so prevalent?  Was it brought in as a dooryard plant (and for what purpose) one hundred, or 150 years ago?  I first saw it growing around the old homesite on the property, along with catnip.  Where it proliferates now, in the forest, it is accompanied by large stands of nettles and catnip, as well as bull thistle.  Also becoming prominent in these areas is European gromwell.

Since arriving back in Door County, I found quite a bit of interesting information about Hound's Tongue, also known as Gypsy Flower, on the Internet.  It is listed as a noxious plant and as invasive in several states and parts of Canada, and it is toxic to animals.  It turns out I was doing the right thing in terms of "management" by pulling the entire plant; plants that are mowed or clipped can come back or even persist for three or more years.

I have not seen Hound's Tongue in Door County - but if it should show up, it would need to be tackled before it has a chance to establish itself.  Its large leaves even on first year plants are very identifiable, and flowering plants even more so, towering two to four feet and covered with reddish-purple blossoms.

More information about Hound's Tongue:

USDA Forest Service

USDA PlantProfile with picture 

Wisconisn Botanical Information System