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Centaurea Species, Black Knapweed, Hardheads, Lesser Knapweed, Spanish Buttons

Centaureanigra

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Centaurea nigra by kennedyh
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Family
Asteraceae (ass-ter-AY-see-ee)
Info
Genus
Centaurea (sen-TAR-ee-uh)
Info
Species
nigra (NY-gruh)
Info
Synonym
Sun Exposure
Full Sun
Foliage
Herbaceous
Height
12-18 in. (30-45 cm)
18-24 in. (45-60 cm)
24-36 in. (60-90 cm)
Spacing
3-6 in. (7-15 cm)
6-9 in. (15-22 cm)
9-12 in. (22-30 cm)
12-15 in. (30-38 cm)
15-18 in. (38-45 cm)
18-24 in. (45-60 cm)
24-36 in. (60-90 cm)
36-48 in. (90-120 cm)
4-6 ft. (1.2-1.8 m)
6-8 ft. (1.8-2.4 m)
8-10 ft. (2.4-3 m)
10-12 ft. (3-3.6 m)
12-15 ft. (3.6-4.7 m)
15-20 ft. (4.7-6 m)
20-30 ft. (6-9 m)
30-40 ft. (9-12 m)
over 40 ft. (12 m)
Hardiness
USDA Zone 7a: to -17.7 °C (0 °F)
USDA Zone 7b: to -14.9 °C (5 °F)
USDA Zone 8a: to -12.2 °C (10 °F)
USDA Zone 8b: to -9.4 °C (15 °F)
USDA Zone 9a: to -6.6 °C (20 °F)
USDA Zone 9b: to -3.8 °C (25 °F)
USDA Zone 10a: to -1.1 °C (30 °F)
Danger

Unknown - Tell us

Bloom Color
Pink
Bloom Time
Mid Summer
Late Summer/Early Fall
Other Details
Category
Perennials
Water Requirements
Drought-tolerant; suitable for xeriscaping
Average Water Needs; Water regularly; do not overwater
Foliage Color
Blue-Green
Orange/Apricot
Where to Grow
Grow outdoors year-round in hardiness zone
Can be grown as an annual
Bloom Characteristics
This plant is attractive to bees, butterflies and/or birds
Bloom Size

Unknown - Tell us

Other details
May be a noxious weed or invasive
Soil pH requirements
6.1 to 6.5 (mildly acidic)
6.6 to 7.5 (neutral)
7.6 to 7.8 (mildly alkaline)
Patent Information
Non-patented
Propagation Methods
Self-sows freely; deadhead if you do not want volunteer seedlings next season
Seed Collecting
Bag seedheads to capture ripening seed
Collect seedhead/pod when flowers fade; allow to dry
Allow pods to dry on plant; break open to collect seeds
Allow seedheads to dry on plants; remove and collect seeds
Unblemished fruit must be significantly overripe before harvesting seed; clean and dry seeds
Properly cleaned, seed can be successfully stored
Regional

This plant is said to grow outdoors in the following regions:

Washington, Maine

Knoxville, Tennessee

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3 members have or want this plant for trade

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charlotte35
Washington, ME (Zone 4a) | August 2006 | neutral

This plant "volunteered" in my yard last summer (2005). It's come up again this year in the same place. It's been identified differentl...Read More

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