What hardiness zones is Cirsium vulgare suitable for?

Cirsium vulgare is suitable for USDA hardiness zones 3, 4, 5, 6, 7, 8, 9.

What are the sun requirements for Cirsium vulgare?

Cirsium vulgare requires Full Sun.

How much water does Cirsium vulgare need?

Cirsium vulgare has Medium water needs.

Herbaceous

Cirsium vulgare

bull thistle

Asteraceae

Europe, western Asia, northern Africa

At a Glance

TypeBiennial

HabitUpright

FoliageDeciduous

Height24-72 inches (60-180 cm)

Width18-36 inches (45-90 cm)

Growing Zones

USDA Hardiness Zones

3 - 9

Zone 3

Zone 4

Zone 5

Zone 6

Zone 7

Zone 8

Zone 9

These zones indicate the coldest temperatures this plant can typically survive.

Frost Tolerancehardy

Key Features

Attracts Pollinators

Attracts Butterflies

Attracts Hummingbirds

Deer Resistant

Drought Tolerant

Fragrant (light)

Maintenancehigh

Overview

Cirsium vulgare is a coarse, spiny biennial in the daisy family (Asteraceae) reaching 24–72 inches (60–180 cm) tall with an 18–36 inch (45–90 cm) spread. First-year plants form a large, flat rosette of deeply lobed, spiny leaves 6–15 inches (15–38 cm) long, dark green and rough-prickly above, gray-woolly beneath. Second-year stems are erect, branching, and conspicuously winged by decurrent leaf bases with stiff, yellow-tipped spines along the wings. Flower heads are solitary or clustered at branch tips, 1.5–2 inches (4–5 cm) in diameter, with purple to magenta tubular florets emerging from a spiny, cobwebby involucre. Pappus bristles are feathery (plumose), distinguishing Cirsium from Carduus (simple bristles). Each plant produces 4,000–10,000 seeds that disperse by wind. Seeds remain viable in soil for 3–5 years. Plants develop a fleshy taproot in the first year, reaching 12–28 inches (30–70 cm) in depth. Unlike C. arvense, bull thistle does not spread by creeping lateral roots and is strictly seed-dependent for reproduction. Listed as a noxious weed in multiple U.S. states. Dense infestations form in overgrazed pastures, clearcuts, and disturbed roadsides.

Native Range

Native to Europe, western Asia, and northern Africa, occurring in meadows, roadsides, pastures, and forest clearings from sea level to approximately 7,500 feet (2,300 m). Introduced to North America, Australia, and New Zealand. Naturalized across all 50 U.S. states and all Canadian provinces.

Suggested Uses

Used in weed identification training for differentiating thistle genera (Cirsium versus Carduus versus Centaurea) based on pappus type and stem wing characters. Studied in rangeland management and biological control ecology. Seeds are an important food source for goldfinches. Flower heads visited by bumblebees and painted lady butterflies.

How to Identify

Distinguished from Cirsium arvense (Canada thistle) by the spiny-winged stems (versus smooth, unwinged stems in C. arvense), larger flower heads 1.5–2 inches (4–5 cm) versus 0.5–0.75 inch (12–18 mm), and solitary rather than colonial growth habit. Distinguished from Carduus species by the feathery (plumose) pappus bristles versus simple unbranched bristles. The upper leaf surface is rough and prickly to the touch, with stiff hairs arising from small raised bases. First-year rosettes are identified by the combination of spiny leaves that are gray-woolly beneath.

Appearance

Size & Dimensions

Height2' - 6'

Width/Spread1'6" - 3'

Colors

Flower Colors

purple

pink

Foliage Colors

green

gray

Fall Foliage Colors

no change

Bloom Information

Bloom Period

~8 weeks

SummerFall

Flowers from June through September in the second year. Individual flower heads bloom for 5–8 days. Flowering progresses from the terminal head downward over 6–8 weeks. In the Pacific Northwest, peak flowering occurs in July through August. Seeds mature 2–3 weeks after pollination and disperse by wind via the plumose pappus. Pollinated by bumblebees, butterflies, and hummingbirds.

Detailed Descriptions

Flower Description

Purple to magenta

Foliage Description

Dark green above, gray-woolly beneath; deeply lobed with stiff yellow-tipped spines; upper leaf surface rough and prickly

Growing Conditions

Sun Requirements

Full Sun

Partial Shade

Requires 6-12 hours of direct sunlight daily

• Full Sun: 6+ hours of direct sunlight

• Partial Shade: 3-6 hours of direct sunlight

• Full Shade: Less than 3 hours of direct sunlight

Soil Requirements

pH Range5.5 - 8.0(Neutral)

357912

Soil Types

loamclaysandsilt

Drainage

average

Water & Climate

Water Needs

Medium

Frost Tolerance

hardy

Time to Maturity

1-2 years

Drought Tolerance

Drought tolerant when established

Care & Maintenance

Care Guide

Management focuses on preventing seed production. First-year rosettes are dug out by severing the taproot 2–4 inches (5–10 cm) below the soil surface; incomplete removal results in regrowth from the root crown. Second-year plants are cut at ground level before flower heads open. Because reproduction is entirely by seed (no vegetative spread), preventing seed set for 3–5 consecutive years exhausts the soil seed bank. Mowing at the early bud stage is effective if timed before any heads open; late mowing allows some heads to produce viable seed. The biological control agent Rhinocyllus conicus (seed-head weevil) was released for Carduus thistles and also attacks bull thistle, though its use is now restricted due to non-target feeding on native Cirsium species. Dense spines make handling without heavy leather gloves impractical.

Pruning

No pruning applicable. Management involves cutting or digging plants before flower heads mature seed. Cutting second-year stems at ground level during early bud stage prevents seed set. Plants do not resprout from roots if the entire crown is severed below the soil surface. Cut material with developing flower heads should be removed from the site.

Maintenance Level

high

⚠️ Toxicity Warning

Non-toxic