Species Canada Thistle
light-purple flowers with purple-brown buds, green leaves and green-brown stems

Canada Thistle

Cirsium arvense

Also Known As - Creeping Thistle
Canada Thistle (Cirsium arvense) is an invasive, climatically adaptable plant species. It is native from Eurasia, and now widely distributed throughout North America. It has bluish green, waxy leaves, grows up to 40-50 cm tall in a clump. It has several hollow purple stems with sharp prickles. Flowering occurs in late summer, producing small white to violet or purple flowers. Canada Thistle is adapted to a wide range of climates and is difficult to eradicate. It can spread rapidly and can outcompete native vegetation. Managed programs of control are the most effective way to reduce its impact.

Watering:

Average

Propagation:

Division,Root Cutting,Seed Propagation,Stem Propagation

Hardiness Zone:

Flowers:

Purple|White/Cream|Pink Flowers

Sun:

Sun, Partial Shade

Soil:

Clay, Sand

Leaf:

Yes

Leaf Color:

green,gray,gray

Growth Rate:

High

Thorny:

Yes

Invasive:

Yes

Care Level:

Medium

watering

For Canada Thistle, water regularly and deeply once a week during the growing season (spring and summer). Make sure to check soil moisture before watering to ensure the plant is neither too wet nor too dry. Avoid wetting the leaves, as this may increase the risk of certain diseases. During periods of extreme heat, water more frequently but reduce the amount given each time. In the winter, water only occasionally and just enough to moisten the root zone.

sunlight

Canada Thistle (Cirsium arvense) needs direct sunlight for optimum growth. The plant needs full sun for about 6 to 8 hours per day. It is important to provide it with as much sunlight as possible to ensure maximum flowering and growth. If possible, provide the Canada Thistle with a south-facing location, which offers maximum sun exposure. In addition, the plant should be given a few hours of shade during the hottest parts of the day so that the plant does not become stressed or dehydrated.

pruning

Canada Thistle should be pruned in late fall or early winter after the plant has become dormant. Pruning should be moderate, removing no more than a third of the plant’s growth each time. Cutting back to a bud will help to prevent regrowth of the plant, as any part of the root left in the soil is capable of regrowth. Cutting deeply into the plant and removing as much of the root as possible will ensure that the Canada Thistle does not sprout again. Along with cutting, consider applying a pre-emergent herbicide prior to pruning susceptible plants. This will help reduce the sprouting of new Canada Thistle plants.

Season

Fall
Winter
Spring
Summer
Sep
Oct
Nov
Dec
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Starts Flowering

Canada Thistle typically starts flowering in June.