We are going to start doing a invasive species series on the blog called “Weed of the Week”. It may come out less than weekly but “Weed of the Week” sounds a lot better than “Weed of about every once a month or so”.
Tumbleweed or Russian Thistle(Salsola tragus) is going to kick off the series. If you have visited Cottonwood Canyon State park, Central or Eastern Oregon, the Western United States, any state other than Florida, or watched a western film, then odds are you have seen tumbleweed.
Usually when folks think of tumbleweeds they picture the rural west and spaghetti westerns might come to mind. You can probably picture one tumbling down a dirt road right now. They are not a native plant however and they are considered a weed.
Russian Thistle is native to Eurasia and is believed to have come to the United States via contaminated flax seed brought by Russian immigrants in the 1870’s. After landing in South Dakota it spread quickly across the United States and Canada and soon became synonymous with the wild west.
Russian thistle is a bushy summer annual that can grow upwards of 5 feet in diameter. It thrives in disturbed soil, so along roadways, freshly plowed areas, and new construction it can quickly become established. As the name tumbleweed suggests, these plants at maturity break off from their taproot and can tumble across the landscape dropping seeds as they go. A large plant can produce as many as 200,000 seeds. Russian thistles are highly drought resistant and need very little rainfall in order to germinate, this often gives them a headstart against desirable plants.
*These control methods are not exhaustive and are for information only
Mechanical- Pulling or hoeing Russian thistle can be highly effective especially in small infestations. The earlier the plant is removed from the ground the better, but as long as the plant hasn’t gone to seed, pulling is effective. Remember each plant pulled can stop 200,000 seeds in the future.
Cultural- Livestock will eat young plants, but not once they get larger. Planting competing species in a managed landscape may work well.
Biological- A leaf mining moth and stem boring moth have been released as biocontrol agents, but control has been poor.
Chemical Control- There are many chemicals out there that will control Russian thistle. Most broadleaf selective herbicides work well such as 2,4-D or Dicamba. With 2,4-D the key to effectiveness is usually to apply early when the plants are young and rapidly growing for greater control. Glyphosate will control Russian thistle but it is not a selective herbicide, so care where applying especially around desirable plants is very important. With any chemical control it is always important to read and follow the label and to make sure you have the proper training and licensing to apply herbicides.
Usually a variety of control methods is best and having and sticking to an Integrated Pest Management Plan (IPM) is highly beneficial in the long run.
For a more exhaustive list on control methods and for more information on Russian Thistle Click Here.
If you have suggestions for future article, questions about Russian Thistle, weeds, or Cottonwood Canyon in general feel free to comment or email me at Asa.Miller@oregon.gov
I tried searching for a good poem about Tumbleweeds but all that I came up with were poems that were mostly romanticizing the weed. So I decided to write my own and now you are stuck with it.
Tumbleweeds are to the West
As Hank is to a song
You think that you know best?
Then let me prove you wrong
Tumbleweeds came to the US from Flax
They came to the midwest from Russia
Tumbleweeds are the cowboy’s tax
To rid them we’ll need a militia
There is some hope in our vision
We will stick to our IPM
We may even resort to ignition
which always makes us grin
Soon they won’t roll down the road
we’ll remove them from our sight
Finally gone from our workload
We might get some sleep tonight
Weed Control in Natural Areas in the Western United States
University of California
University of California Agriculture and Natural Resources