Cirsium muticum, known as Swamp Thistle, is a biennial that can reach heights of up to 8 feet, but is typically around 5 feet. It has spiny leaves and produces pink to purple flower heads from mid-summer to early fall. This species is commonly found in wet habitats such as swamps, bogs, and wet meadows. Swamp Thistle is suitable for naturalizing in wet areas, wetland restorations, and is a great nectar source for pollinators.
Characteristics
Type
Forb
Sun
Full Sun, Partial Sun
Soil
Loam, Sand/Gravel, Peat, Calcareous
Moisture
Wet
Average Max Height (inches)
72
Suggested Plant Spacing (inches)
30
Bloom month(s)
July, August, September, October
Bloom Color or Type
Violet
Dominance
Low
Range Maps
Sowing Information
Sow seed onto a firm, weed-free seedbed. Hand-broadcast seed making two perpendicular passes for even coverage. If planting a mix, broadcast the grass component first and lightly rake/drag it into the top 1/8–1/4" of soil. Next, broadcast wildflower/forb seed and press it into the soil surface (with a roller/cultipacker or the back of a rake) to ensure good seed-to-soil contact. After seeding, apply a very light layer of clean, seed-free straw (or other weed-free, site-appropriate mulch) to reduce erosion and retain moisture without smothering seedlings. A good rainfall or thorough watering will help settle seed and mulch and improve germination.
Planting Information
Dig a hole in your planting site slightly larger than the plant’s root system. When placing the plant into the hole, ensure that the soil line remains consistent with its original level in the pot. Fill in around the roots with the excavated soil, gently firming it to eliminate air pockets. Water the plant thoroughly the same day to promote successful establishment.
