Thistle and Crown Vetch

pagirl(z6PA)July 22, 2005

I made a huge mistake three years ago when I had a new home and they asked to spray crown vetch on my rather steep slope in the back yard sloping down and away from the yard. Now it is taking over the yard and thistles have come up everywhere in the crown vetch and are also encroaching into the yard. I tried pure vinegar on the thistles that were in the yard but they keep coming back. I want to kill off the entire hill and try something else. Two questions. How to kill off the thistles and crown vetch? Any ideas for a good ground cover for full sun?

Thank you for reporting this comment. Undo
Judy_B_ON(Ontario 5B)

Thistle is very hard to kill as any tiny piece of root left behind will grow into a new plant.

Best suggestion is Round Up, even then it will likely take several applications to get rid of thjistle. Weeds sprayed with Round up take about a week to start to turn brown, respray any green bits again 10 days after the first spray.

    Bookmark   July 23, 2005 at 5:55PM
Thank you for reporting this comment. Undo

I planted ONE crown vetch 4 years ago (duhhh---I didn't know!!). Within two months I noticed it was choking out one of my prized hydrangeas, so I promptly yanked it out. I've sprayed Round Up anytime I saw a new one peeking through the soil. Last year, I ended up tearing ALL of my perennials out of that particular bed and doing a RU soak. I've only had one come up this year. I still don't dare put anything but annuals in this bed until I know it is eradicated!!! P.s. I ended up throwing away most of the perennials for fear of transplanting CV roots with them.

    Bookmark   July 25, 2005 at 5:02PM
Thank you for reporting this comment. Undo

Thanks. I have about 1/8th of an acre covered with this stuff so I guess I will try to gradually kill it with RU.

    Bookmark   August 1, 2005 at 5:20PM
Thank you for reporting this comment. Undo
phacops(central PA)

We've never planted crown vetch on our property, and PennDot has not planted crown vetch anywhere near us, but we have the darn stuff coming up everywhere. My wife and I are adverse to using herbicides, so I've had to take another approach. And that is to take my brushcutter and basically scalp the area with crown vetch. Ideally the weather will be hot, dry, and windy. The grass recovers from the scalping but the crown vetch generally does not, at least if I get to the stuff before gets really established (maybe because the roots are still shallow and dry out?). However this is not permanent. The stuff is very prolific when it comes to seeds; I'm sure some to the "regrowth" each year is really the result of leftover seeds germinating. Still, I am making progress even though I expect that I'll never completely eliminate the stuff.

    Bookmark   August 2, 2005 at 1:55PM
Thank you for reporting this comment. Undo

This may be a little bit off topic, or maybe it's still on the topic. A couple of Summer's ago, I fell in love with crown vetch. My parent's had chosen to plant it around a small pond that my Father built and it grew like crazy all around it! I use to love this wildflower as a child and played with it a lot. I really love it because it smells like watermelons! Do you think it smells like that too? Just curious...

Also, there's this similar wildflower that also looks a whole lot like crown looks exactly the same, but instead of the beautiful light, pastel purple flowers with white, this 'other' kind has yellow and white petals. Is that a wildflower related to the crown vetch?

One last thing I would like to mention here is, is I also fell in love with the tiny little green faced winged bee's or fly's that hung around the crown vetch too. There were handfuls of them hanging around, sipping each little flower all day long. Does anyone know what they are or are called? They're not your, usual honey bee's either...they were very small, had small black eyes and had a greenish color to them. If anyone knows anything about what I'm talking about, please tell me more because I love them and are very curious about them...

thank you

    Bookmark   June 12, 2007 at 12:42PM
Thank you for reporting this comment. Undo

Does anyone know how and when to transplant mature crown vetch? Best time of year? How close together?

Please send your answers to

I can never find the answers to these posts, and never get help with how to look for them. It's a mess to me. Thanks.


    Bookmark   June 18, 2007 at 11:52PM
Thank you for reporting this comment. Undo

Glad to see I'm not the only one who is plagued by this weed from he** !! I first saw it in our weed patch 3 years ago and thought, "Huh, it looks like someone must have dumped out a load of ground that has crown vetch in it!" and I loved the smell of the flowers. The next year I thought, "Wow, it sure spread and it'll really smell good here now." Then last year I was becoming concerned because it really was spreading fast and really didn't want it taking over everying (btw, it WILL if you let it!). I found the forums and did a lot of reading on the Internet and now know pretty much about native wildflowers (of which crown vetch is NOT). After all of my research, I finally came to my senses (well, I was actually ignorant before doing a lot of reading) and realized that this obnoxious invader HAS to be destroyed if I value the native plants that it's crowding out. So this year will be my first year in my quest to ERADICATE the crown vetch so the native plants can have their space back again someday.

    Bookmark   January 22, 2008 at 4:44AM
Thank you for reporting this comment. Undo

Thistle can be a major problem because many birds like the seeds and spread them around as they eat them and fly here and there, and because they produce many seeds that easily float on the wind, and they also spread by the root system. However, if the plant is kept cut it will die out.
Crown vetch is easily kept under control by mowing.
Anything you can spray that will kill these plants will alos kill any other plant the spray contacts and good research has shown that these sprays do have an adverse affect on the Soil Food Web and then those things that feed on the Soil Food Web.

    Bookmark   January 22, 2008 at 7:07AM
Thank you for reporting this comment. Undo

I was looking for a way to get rid of vetch... The missouri department of conservation suggests the use of Clopyralid... The problem is that this herbicide is persistent!!! I use compost and mulch of lawn clippings in my vegetable garden... i try and keep it as free of chemicals as possible! Using grass clippings from a treated lawn as mulch will apparently kill your tomatoes, peas, beans and other plants in your garden... It lasts for years too so your compost and mulch becomes toxic to the plants your trying to grow!

I'm really glad I ran across this article in the Mother Earth news, before I got any of this herbicide!!!
Milestone Herbicide Creates Killer Compost

Here is a link that might be useful: Milestone Herbicide Creates Killer Compost(mother earth news)

    Bookmark   July 16, 2013 at 10:36PM
Thank you for reporting this comment. Undo
kimpa(z6b PA)

Crown Vetch is recommended for stabilizing slopes. Soil can erode if you don't have something "good" there. So that depends on how steep and large is the area? Now if you were able to get rid of the thistle, would you keep the crown vetch? Thistle is hard to kill and will probably need repeat applications. In the meantime, don't let the thistle go to seed. At least cut off the flowers and you will have more time to decide.

    Bookmark   July 19, 2013 at 8:47AM
Thank you for reporting this comment. Undo

This article may be of interest to some that think the glyphosates are not harmful to the environment.

Here is a link that might be useful: About glyphosates

    Bookmark   July 20, 2013 at 7:04AM
Sign Up to comment
More Discussions
So I've hoed hound now what?
So it's that time of year I have started to notice...
Ailanthus Advice?
I've cross-posted this from the Trees Forum, but am...
Weed Identification (Florida)
Good afternoon, I have a problem with a weed (type...
The battle against Bermuda
Tilled a new spot back in late summer. In my past experiences...
Prevent new plants from growing
My garden contains roses, shrubs, gazanias, ornamental...
People viewed this after searching for:
© 2015 Houzz Inc. Houzz® The new way to design your home™