Spotted Knapweed

Spotted Knapweed is invading our county here in Missouri. According to the local University of Missouri Extension office, until recently, Missouri has not had an invasive problem with this noxious weed. Now, however, this plant is a common sight along roadsides, in pastures and in unused grass land areas.

Spotted Knapweed is a problem in that it emits a noxious chemical called Catechin. Catechin is emitted from the roots of the Knapweed and acts as an herbicide that inhibits the growth and germination of nearby weeds and desirable forage grass.

Spotted Knapweed can be spread through various methods including wildlife, cattle and from the undercarriage of vehicles, which would explain the abundance of this weed in power company right of ways. Wind, however, does not seem to be a factor in the spread of the weed as it seems that most new growth takes place in an area of 40 feet around existing plants.

Knapweed produces around 1,000 seeds per head and the seeds can survive in the soil for eight years. The seed can even be carried down a stream and rest in a place that will allow it to grow.

Cattle will not eat this weed (I'll have to see what Kath Voss of livestock for landscapes would have to say about this) as it is not palatable and tough. Goats and sheep will readily eat it and may be used in an effort to control it. Other methods of eradication are either spot spraying or broadcast spraying. For broadcast spraying, the extension office recommends Tordon 22K at one pint per acre. For spot spraying, use Milestone at five or seven fluid ounces per acre. We like things natural here, so I would opt for the sheep or goats.

One thing to consider, if you don't have a problem with Spotted Knapweed now, you might if you buy in your hay. Hay from outside sources can be contaminated with a variety of undesirable weed species.

If Spotted Knapweed has already become a problem (it is listed as a noxious weed in 15 other states), cultural methods of control such as mowing or grazing alone may not solve the infestation problem.

I haven't seen this weed on our land yet, but it is all over our county. I do purchase our hay from an outside source and I will have to be careful not to let unwanted seed get spread out in the pastures. Good advice for us all, I think.

Hey folks! This is my 100th post on this blog! Thanks to all of you who come here to read my ramblings and share in what I have learned. I wouldn't do it if I knew no one was reading it, thanks again and keep coming back for another 100 posts! I hope you enjoy it. If you have any suggestions on what I can do better or ideas for articles or just a question or comment, please feel free to let me know, I am glad to listen.