Native thistles in Gilpin County
You've learned about how bad some thistles can be for our environment.
You're primed and ready to pull or spray. Good for you! But before
you target all thistles, remember that there are 20 native thistle
species in Colorado, and these play an important role for wildlife.
Native thistles should not be killed, because they are not noxious
weeds.
How do you tell a native thistle from a noxious thistle?
Generally, if the stand of thistles is very dense or very tall
(6’), it is usually noxious.
If you are above timberline and see a thistle, it’s probably
native.
Native thistles tend to be short, and are usually only found as
individual plants or in very small groups of 2-4 plants.
A thistle with a white flower (the FLOWER, not the fluffy dandelion-like
seeds), is probably native.
Pictures of native thistles in Gilpin County
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Fringed thistle
Cirsium centaureae
- native
Note reddish stem and whitish brown flowers. This is very
commonly found in Gilpin County. Flowers are buff-colored. |
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Mountain thistle
Cirsium scopulorum
- native
(found in subalpine and alpine) |
 |
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Meadow or Elk thistle
Cirsium scariosum
- native
This thistle can either be stemless (as pictured), or have
a short stem. |
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Prairie or Platte thistle
Cirsium canescens - native
This thistle is light pink (or even white) Also note the
white line on the bracts. Leaves are blue-green. |
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