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Centaurea macrocephala (Giant knapweed, Yellow hardhead)

Centaurea macrocephala Photo/Illustration: Jennifer Benner

(Based on 2 user reviews)

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Hardiness Zones: 1 2 3 4 5 6 7 8 9 10 11
Botanical Name: Centaurea macrocephala Common Name: Giant knapweed, Yellow hardhead Genus: Centaurea
This clumping, robust perennial has unusual ramrod-stiff flower stems that bloom from early summer through late summer. Its fat, rusty buds open into large, deep yellow thistle flowers the size of a small fist. Easy to cut and dry for arrangements. This plant has big, coarse leaves that call for strong companions.
 Noteworthy characteristics: A tricky plant to work into a perennial garden because it draws a lot of attention.
 Care: Grow in moist soil in sun or partial shade.
 Propagation: Start seeds in a cold frame in spring, or divide plants in spring or fall.
 Problems: White mold, rust, mildews, thread blight, and Southern blight.
Height 3 ft. to 6 ft.
Spread 1 ft. to 3 ft.
Growth Habit Clumps
Light Full Sun to Part Shade
Moisture Medium Moisture
Characteristics Showy Flowers
Bloom Time Summer
Flower Color Yellow Flower
Uses , Cut Flower, Cottage Garden
Style , Rock Garden
Seasonal Interest , Summer Interest
Type ,Perennials

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