Russian Thistle

Scientific Name:Salsola kali (also Salsola tragus and Salsola iberica)

Family: Chenopodiaceae (Goosefoot Family)

Other common names: tumbleweed, prickly Russian thistle

Life-Cycle: Annual; spreads only from seed

Russian Thistle Quick Guide


Description
Bloom
(varies by elevation)

What to Do

When?

Invades Undisturbed Land
State Class
Slender, fleshy seedlings; red-striped stems; becomes 2-3 ft tall, prickly and woody then breaks off as a tumbleweed.
Small, petal-less bloom of white or pink occurs up the length of the stem at each spiny leaf in July & August.
Hand pull or hoe seedlings; cultivate soil; plant competing vegetation
June through August
Typically no. Needs loose, disturbed soil to germinate; is most common along roads, trails and driveways.

None

Innocent, wispy, young Russian Thistle
The nasty, prickly tumbleweed we recognize

General Description
. Russian thistle is least noticed when it is young - slender, green and soft - and most noticed when it's a large, spiny, brown tumbleweed.
. Flexible, almost succulent, green (or sometimes pink) stems have red/purple vertical stripes, and are multi-branched to the point of becoming a bushy bramble as plant grows.
. Fine, long leaves that look like soft pine needles are reduced to short, prickly spines as the plant ages over the summer.
. Tiny flowers are basically unnoticeable without close inspection, but they are attached directly to the stem, white to pink and relatively attractive (see photo above, right).
. Russian thistle does not like firm, well-irrigated soil (around your house); look for broken chunks of dried Russian thistle along roads, driveways and trails.

Life-Cycle
. An annual, each plant dies every year and new plants grow from seed.
. Germinates between late April and August; flowers late June through August; goes to seed August to November; dies after the first fall frost and breaks at the base of the stem now through the following spring to spread seed as a tumbleweed.
. Seeds need loose soil and are not viable for more than a year or so (meaning, you can beat this weed!).

Prevention & Control

    Prevent
    . Detect and eradicate new plants early; look for last year's tumbleweeds as a clue.
    . Do not drive vehicles and machinery through areas with old tumbleweeds.
    . Screen irrigation water before it enters a field or your irrigation pipes.

    Hand-Pull
    . Hand-pulling or hoeing is the best and easiest method for small or sporadic patches as the roots are shallow and the plant grows from seed (not roots).
    . Seeds germinate throughout the spring and summer so check your property often.

    Mowing, Grazing, Cultivation & Biocontrols
    . Mowing or otherwise destroying young plants prevents seed production.
    . Planting competitive desirable species, such as tall grass or shrubs can effectively shade out sunlight and suppress weed seedlings.
    . Grazing works well for young plants.
    . Several potential biocontrols are under investigation but none exist now.


See the whole “Toolbox of Weed Control Methods” for more details.

Interesting Tidbits
. Russian thistle is the primary host for the beet leafhopper (Circulifera tenellus) that carries the "curly-top virus" of sugar beets, tomatoes, squashes, melons and cucumbers.
. Russian thistle tumbleweeds present a serious fire hazard.

Resources & Photos

* Okanogan County Noxious Weed Control Board

* More Images: http://biology.burke.washington.edu/herbarium/imagecollection/taxon.php?ID=1334

 

 
 
 
 
 
 
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