Botanical profile

Centaury

Latin name
Knapweed
Common name
Centaury
Type
Perennial or flowering annual
Family
Asteraceae

Depending on the variety, cornflower is a perennial or annual plant, valued for its light, colorful, and very natural blooms. Its finely cut petals, often blue, mauve, pink, white, or purple, bring a rustic charm to flowerbeds, borders, pollinator gardens, and naturalized landscapes. Its delicate appearance pairs very well with grasses, yarrow, echinacea, daisies, and other prairie-style perennials.

Easy to grow, cornflower generally prefers a sunny location and well-drained, light to moderately fertile soil. Once established, it requires little maintenance and tolerates drier conditions quite well, making it an excellent plant for low-maintenance gardens, rockeries, embankments, and sunny borders. Removing faded flowers helps prolong blooming and keeps the plant tidier throughout the season.

Highly valued by bees, butterflies, and other pollinators, cornflower helps create a vibrant, colorful, and biodiverse garden. Some varieties are also excellent as cut flowers thanks to their delicate and decorative floral stems. It is an ideal plant for adding color, movement, and an elegant wild touch to outdoor spaces, while promoting the presence of beneficial insects in the garden.

Care guide

Care level
Easy

Choosing this plant

Main benefit
Highly decorative and melliferous wildflowers
Flowerbeds, wildflower meadow, borders, cut flowers, pollinator garden
Container growing
Potted cultivation possible in a well-drained container
Seasonal care
Deadhead spent flowers to prolong blooming; cut back dry foliage in the fall or spring.
Growing conditions

Light, soil, water and hardiness

Hardiness zone
Non-hardy (annual crop)
Exposure
Full sun
Watering
Moderate; allow the soil surface to dry slightly between waterings
Humidity
Low to moderate humidity; tolerates slightly dry soil
Fertilization
Light compost in spring; avoid excessive fertilizer
Soil type
Light to medium, well-drained, even poor soil
Soil pH
Neutral to slightly alkaline
Minimum temperature
-30°C
Propagation method
Sowing or division
Plant appearance

Blooming, foliage and shape

Blooming period
Spring to summer
Flower color
Blue, pink, mauve or white depending on the cultivar
Fruiting
Decorative seed heads at the end of the season
Foliage color
Green to silvery-grey depending on the species
Foliage type
Obsolete
Shape
Upright or clumping habit depending on the species
Garden structure

Size and growth

Height
45 to 90 cm (18 to 36 inches)
Width
30 to 60 cm (12 to 24 inches)
Growth rate
Average growth
Vegetable garden and yield

Companion planting, spacing and harvest

Companion plants
Yarrows, coneflowers, ornamental grasses, lavender
Plants to avoid
Avoid with very covering or invasive plants
Spacing
30 to 45 cm (12 to 18 inches)
Harvest period
June to August
Pet friendly
Safe for pets

Pets

Deer
Less attractive or generally tolerated by deer

Deer

The availability of our plants varies depending on arrivals, seasons, nursery production and supplier availability. Some varieties may be offered for a limited time only, depending on their natural cycle or current stock. These plant profiles are designed to guide and inspire you when choosing plants for the garden, landscaping projects, containers or long-lasting outdoor arrangements.