Canada Thistle, Creeping Thistle, California Thistle
Cirsium arvense

Family: Asteraceae (ass-ter-AY-see-ee) (Info)
Genus: Cirsium (SIR-see-um) (Info)
Species: arvense (ar-VEN-see) (Info)
Synonym:Carduus arvense

Category:

Perennials

Foliage Color:

Silver/Gray

Bloom Characteristics:

This plant is attractive to bees, butterflies and/or birds

Water Requirements:

Drought-tolerant; suitable for xeriscaping

Average Water Needs; Water regularly; do not overwater

Where to Grow:

Unknown - Tell us

Height:

24-36 in. (60-90 cm)

36-48 in. (90-120 cm)

4-6 ft. (1.2-1.8 m)

Spacing:

15-18 in. (38-45 cm)

Hardiness:

USDA Zone 3a: to -39.9 C (-40 F)

USDA Zone 3b: to -37.2 C (-35 F)

USDA Zone 4a: to -34.4 C (-30 F)

USDA Zone 4b: to -31.6 C (-25 F)

USDA Zone 5a: to -28.8 C (-20 F)

USDA Zone 5b: to -26.1 C (-15 F)

USDA Zone 6a: to -23.3 C (-10 F)

USDA Zone 6b: to -20.5 C (-5 F)

USDA Zone 7a: to -17.7 C (0 F)

USDA Zone 7b: to -14.9 C (5 F)

USDA Zone 8a: to -12.2 C (10 F)

USDA Zone 8b: to -9.4 C (15 F)

USDA Zone 9a: to -6.6 C (20 F)

USDA Zone 9b: to -3.8 C (25 F)

USDA Zone 10a: to -1.1 C (30 F)

USDA Zone 10b: to 1.7 C (35 F)

Sun Exposure:

Full Sun

Sun to Partial Shade

Danger:

Plant has spines or sharp edges; use extreme caution when handling

Bloom Color:

Magenta (Pink-Purple)

Violet/Lavender

Purple

Cream/Tan

Bloom Time:

Late Spring/Early Summer

Mid Summer

Late Summer/Early Fall

Blooms repeatedly

Foliage:

Evergreen

This plant is resistant to deer

Other details:

May be a noxious weed or invasive

Soil pH requirements:

6.1 to 6.5 (mildly acidic)

6.6 to 7.5 (neutral)

7.6 to 7.8 (mildly alkaline)

Patent Information:

Non-patented

Propagation Methods:

From seed; direct sow outdoors in fall

From seed; direct sow after last frost

Self-sows freely; deadhead if you do not want volunteer seedlings next season

Seed Collecting:

N/A: plant does not set seed, flowers are sterile, or plants will not come true from seed

Regional

This plant has been said to grow in the following regions:

Hanceville, Alabama

Aurora, Colorado

Lamar, Colorado

Springfield, Colorado

Payette, Idaho

Macy, Indiana

Leavenworth, Kansas

Skowhegan, Maine

Bay City, Michigan

Brainerd, Minnesota

Minneapolis, Minnesota

Ogdensburg, New York

Belfield, North Dakota

Wapakoneta, Ohio

Klamath Falls, Oregon

show all

Gardeners' Notes:

1
positive
4
neutrals
6
negatives
RatingContent
Positive

On Jun 23, 2013, HarrySachs from East Gull Lake, MN wrote:

I like this plant. I like neat looking plants even if it is considered a weed. I have one growing near my bathroom window where my central air is. Under the right conditions the thing is a beast! Keeps people from messing with my AC and walking near my bathroom window.

I suppose if it sends runners I may have a problem. But it cant be any worse than that snake grass and snow on the mountain

Neutral

On Sep 4, 2010, DMersh from Perth
United Kingdom (Zone 7b) wrote:

This grows rampantly in all parts of Britain, easily distinguished from other thistles by its much smaller flower head. Looks nice in autumn when the plants are covered in cotton from the flowerheads, the cotton is attached to the seeds and helps them disperse on the wind.

Negative

On Jul 9, 2009, Ponditis from Lincoln City, OR (Zone 9a) wrote:

I have dealt with this plant my entire gardening life and continue to hate it. Every bit of root you leave behind when pulling them will sprout new growth and the harsh prickles that are on every stem and leaf will go into your gloves, shoes and socks making life miserable for you. It takes at least two sprayings of a broad leaf weed killer to kill the plant and you still have to come back in a couple of weeks to make sure that you have killed the plant. I have read that the seeds last 50 years in the soil and will grow when disturbed. The flowers will continue to go to seed after they have been removed from the roots. My sheep and goats hesitate to eat it since the spines are so sharp. This weed is on most US states noxious weed list and that is where it belongs in my opinion.

Negative

On Feb 22, 2009, katsu from Columbus, OH (Zone 6a) wrote:

Thistle is the worst weed in our yard and garden. It grows so well here that I don't have to worry about depriving the wildlife by killing what's on my property. : )

I used to dislike wearing gloves for gardening, but thistle makes it necessary. My husband likes to use Roundup on them, but then it takes forever for them to die and you are left with the ugly, spiny plant material. I prefer to pull them, on a day after it has rained. More of the root will come up if the ground is moist. It can help to dig a bit of soil away so that you can grab the root itself.

We used a broadleaf weed herbicide on the lawn a couple of years ago, and it seemed to work pretty well.

These buggers even like the very dry, very shady north side of our house.
... read more

Neutral

On Feb 16, 2009, dplooster from Leavenworth, KS wrote:

I love the way these plants look, but had to eradicate a huge colony from ground I wanted for a new garden. The first year, I dug by hand with fair success - as noted, every little bit left resprouts. The second year I sprayed with white vinegar on a sunshiny day. Sunshine is a vital factor in the vinegar's success. Had to repeat the vinegar spray two or three times for some of the hardiest thistles, but definitely the easiest and most effective way. Now, the garden is lovely, but I do miss the thistle blooms - occasionally!

Neutral

On May 31, 2008, donicaben from Ogdensburg, NY wrote:

When it stays near the evergreens, I'm ok with it. I only hate it when it grows in the center of the yard and one of my kids steps on it. :-/

The flowers are pretty, and finches LOVE the seeds. It's cute to watch them sit atop one and nibble away - leaving the fluffly white part of the seeds trail away like clouds. :-)

The only time I see those little yellow guys is when these seeds set.

Negative

On Mar 14, 2008, Malus2006 from Coon Rapids, MN (Zone 4a) wrote:

I hate Canda thistle! They can penerate gloves and are stubborn to remove, can pop up in bushes where removal is difficult. They also gets chewed up by bugs or are coarse. One way I have found to remove this species is by carefully grasping the bottom of the plant where it contact the ground - about a hand's height and then pull on it and keep a vigorous search for any resprouting. The spines is nearly nonexisting on this portion but you have to be careful - leaves can touch the hand. Bull thistle, the only other common weed thistle for the North US is best done in mechanically - even the bottom is very spindly. I have seen huge amounts of roadside covered in Canada thistle - usually in roadside where the soil have not been disturbed since Minnesota stopped mowing most of the roadside e... read more

Neutral

On Aug 10, 2007, kniphofia from Morpeth
United Kingdom (Zone 8a) wrote:

This is such a pretty flower, and the plant is very useful to wildlife, so I leave these in the wilder parts of my garden.

Negative

On Apr 1, 2007, Joan from Belfield, ND (Zone 4a) wrote:

This plant is listed on the North Dakota invasive/troublesome list and this information is being distributed in a guide developed by the ND Weed Control Association and other agencies.

Plant Features
Perennial, up to 4 feet tall
Shiny/waxy/spiny green leaves
Clusters of purplish to whitish flowers
Blooms June through August
Seed head, cotton-like tuft
Mid-spring emergence, plants may also emerge early fall in a rosette stage
Spreads by creeping roots (rhizomatous) and seeds
May form dense patches

Distribution
Widespread invasive that grows under most conditions

Interesting Facts:
Plants are either male or female (dioecious)
Butterflies, such as the ... read more

Negative

On Jan 26, 2003, valdan from Wynndel
Canada wrote:

considered noxious weed in western Canada. Extremely difficult to remove.

Negative

On Jan 25, 2003, lupinelover from Grove City, OH (Zone 6a) wrote:

Canada thistle is only a problem in the northern part of the US and Canada. It has a very extensive root system that breaks easily, and every bit must be removed or it just increases. It grows readily in almost any soil, from dry through wetlands. The seed is so light-weight it can be blown far and wide. It remains viable for years.

The most effective way to remove it is by repeated cutting of foliage until the roots die from lack of nourishment. Chemicals usually must be applied repeatedly because of its very dense root system.