Swamp Thistle

Botanical Name: Cirsium muticum

Height: about 1 m

Season of bloom: Summer.

Growing Conditions: Full sun. Found in the wild growing in moist and calcareous (limestone) situations. Biennial – makes basal rosette in its first year.

Wildlife benefits:  Flowers of Swamp Thistle (and other native Cirsium) attract many insects, especially long-tongued bees and butterflies. Small songbirds eat the seeds of thistles, especially the American Goldfinch. This bird also uses the hair tufts of thistle seeds in the construction of its nests.

From Ottawa Valley or eastern Ontario sources: Yes.

Remarks: Attractive flower buds. Prickly but not nearly as fiercely armed as the non-native Bull Thistle. Swamp Thistle will not seed itself into lawns or other non-wetland areas.

Similar species: Field Thistle

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