Tall thistle (Cirsium altissimum)

Tall thistle

Tall thistle is native to the central and eastern United States and does not bloom until its second year. When it does produce flowers, they are a purplish pink, fragrant, and produce a large amount of nectar that attracts pollinators of all kinds. It dies after flowering.

Scientific classification

Species

Tall thistle (Cirsium altissimum)

Asters bellflowers fanflowers and allies

Instantly identify plants with a snap

Snap a photo for instant plant ID, gaining quick insights on disease prevention, treatment, toxicity, care, uses, and symbolism, etc.

Download the App for Free

Biennial, Perennial

Lifespan

Herb

Plant Type

Summer, Fall

Bloom Time

91 cm to 3 m

Plant Height

50 cm

Spread

Green

Leaf Color

20 - 35 ℃

Ideal Temperature

Quickly Identify Tall thistle

Basal leaves deeply pinnatifid, stem leaves lanceolate to elliptic with lobed margins and spines.

Flowers with vibrant colors like pink to purple, disc florets up to 2 inches (5 cm) wide.

Stem light green to reddish-brown with distinct ridges, densely hairy and sparsely branched.

Fruit composed of bullet-shaped achenes with tufts of cottony white hairs, aiding wind dispersal.

Low-lying rosette in first year, flowering stem reaching 3-10 feet (90 to 300 cm) in second year.

Identify plants with a snap

Instantly identify plants with AI: Snap a photo, and get accurate results within seconds.

Download the App for Free

Care Guide for Tall thistle

Every week

Water

Full sun

Sunlight

20 - 35 ℃

Ideal Temperature

Water: Tall thistle thrives in conditions resembling its native habitat with regular rainfall. It has moderate drought tolerance and should be watered weekly to maintain moist, well-drained soil. Typically grown outdoors, tall thistle requires careful watering during its active growing season for optimal bloom support.

Fertilize: For tall thistle, apply high-phosphorus fertilizers once in early spring at half-strength to enhance growth and flowering. Avoid over-fertilization to protect the plant's habitat. Ensure fertile soil for development, applying recommended doses to maintain health and support the surrounding ecosystem.

Pruning: Tall thistle is a tall, herbaceous perennial with spiny leaves and purple flowers. Prune in early to late spring to maintain shape, remove seed heads to control spreading, and use clean tools to reduce disease risk. Regular pruning promotes healthier growth and robust blooms.

Propagation: Tall thistle thrives in prairies and woodlands, reproducing via seed dispersal. Collect seeds post-bloom when dried, and surface sow for light during germination. Use a well-draining medium, keep it moist, and transplant seedlings with minimal root disturbance for best results.

Get tips and tricks for your plants.

Keep your plants happy and healthy with our guide to watering, lighting, feeding and more.

Download the App for Free

Learn More About Tall thistle