I'm afraid I already know the answer to this question, but I'll give it a try, anyway! Many years ago I was told by a landscaper to plant crown vetch on a steep bank in front of my house. After a few years I realized that this was BAD advice. A couple of years later I called into a national radio garden show to find out how to get rid of the crown vetch and was told to kill it with RoundUp. I then asked how long I should wait to plant something else in its place and was told that once the crown vetch was dried up and dead that it was history. Another bit of BAD advice! I went ahead and planted vinca/periwinkle - which I absolutely love. BUT, of course, the crownvetch still grows, like crazy. I usually spend a whole weekend, once the crown vetch has completely towered over the vinca (and blocks my view when I try to back out of my driveway) to pull the invincible weed out so that the vinca "looks" like it's the only thing growing. Is there anything that I can use to kill the crown vetch, without killing the vinca? The vinca has been growing for a number of years and has covered the bank really nicely, so I'm afraid my options are very limitied. Any ideas???

 

It would be time consuming and likely impossible if the area is large to keep each plant cut down so plants would not photosynthesize. There are several effective herbicides that can be used. These would have to be applied to individual plants, taking care not to get on the periwinkle. This would likely require brushing the herbidicide onto the crown vetch. For herbicides: http://www.in.gov/dnr/invasivespecies/Crown_vetch.pdf







Photo Credit: Panikon

 

Jombill, unfortunately crownvetch was also planted in large drifts along highways to aid in erosion control. That was before we knew... Great site from Twelvepole, but that's quite a list of chemicals. You might want to read about them here.
http://www.pesticide.org/factsheets.html#pesticides

Since the site mentions burning, and you already spend alot of time pulling, etc., maybe using a flame weeder or a radiant heat weeder would work for you. At the first site click on 'Weed Control Tools and Their Effects' and scroll down to 'Flame Weeding'. Lots of other good info there too.
http://attra.ncat.org/attra-pub/weed.html
http://www.pesticide.org/radiant.html
http://www.pesticide.org/pubs/alts/pdf/flameweeding.pdf

Newt

 

I like the idea of flame weeding as a nonchemical control. With persistence and determination, it's possible to eradicate the crown vetch if it not allowed to photosynthesize. Problem is the plant spreads via rhizomes that can reach 10+ feet as well as seeds. Great for stabilizing banks along highways, but is devastating to desirable species.

 

Thanks for all of your ideas. I think I'm going to look into a radiant weeder. I think that will be the best way to avoid indescriminate killing of my vinca! . . . And who doesn't like buying a new "toy"?!!!

 

Radiant Heat Weeders! That sounds better than a flame weeder. No flame!

The following indicates that radiant weeders are more difficult to find in the states than in Europe. It provides a couple of links. http://www.pesticide.org/radiant.html


Photo Credit: pesticide.org

 

Jombill, I hope you return and let us know how it worked for you. I recommend them often but haven't gotten any feedback yet.

Newt

 

I bought a flame weeder for the same type of job because it was less expensive than the radiant weeder. However, I ended up buying a propane tank because my old one didn't fit. I then had to fill it and I needed a hand cart. I don't think I saved much.

 

Hbggardener, thanks for sharing that. I will keep what happened to you in mind when I recommend these weeders to others.

Newt

 

the house I purchased has a large yard that drops down a steep slope which faces the neighbors, not me. Previous owners were not gardening people and let crown vetch take over. Tried using round up in the fall but the steepness made it impossible. Was thinking of using heavy plastic, then mulch but what can I do to make the hill attractive enough for the neighbors and carefree?