Cornflower
centaurea cyanus
Also known as: ["Bachelor's Button","Bluebottle"]
Overview
An annual flowering plant known for its vibrant blue flowers, often found in fields and gardens.
Benefits & Perks
["long-flowering","wildlife attractant (bees, butterflies, birds)","drought tolerant","aesthetic foliage"]
Botanical Classification
| Phylum: | Magnoliophyta |
| Class: | Magnoliopsida |
| Order: | Asterales |
| Family: | Asteraceae |
| Genus: | Centaurea |
| Botanical Name: | Centaurea cyanus |
Plant Characteristics
Basic Information
- Category: Flowers
- Suitable Location: garden bed in open sunny area, or container with adequate drainage
- Suitable For:
- Is Weed: No
- Allergenicity: low
Environmental Needs
- Climate: {"temperatureRange":"5–30°C"}
- Hardiness: {"zones":"3–9"}
- Misting: rarely required, only if ambient humidity is very low
- Drainage: Fast-draining to prevent waterlogging.
- Soil Type: Well-draining, loamy soil with added organic matter; avoid heavy clay soils.
Maintenance Level
- Maintenance Level: low
- Toughness Level: moderate
- Pruning Frequency: Deadhead spent flowers regularly during the growing season; light shaping pruning in early spring.
- Pruning Intensity: Light to moderate; avoid heavy pruning unless necessary to control size.
Care Details
Ideal Sunlight Coverage:
Full sun (6–8 hours of direct sunlight daily); adjust for extreme heat by providing partial shade during peak afternoon hours.
Sunlight Tolerance Tips:
Acclimate plants gradually to direct sunlight if moved from shade; protect from intense midday sun to prevent scorching; for indoor placement, use a south-facing window.
Care Requirements
Care Difficulty
easymoderate
Sunlight
full sun
Rotate plants for even light exposure; use sheer curtains to filter harsh sunlight; avoid placing near large heat-emitting windows.
Watering
every 7–10 days during active growth, reduce in winter
Water thoroughly but infrequently; ensure soil dries between waterings; avoid overhead watering to prevent fungal issues.
Soil
well-drained, sandy loam with moderate fertility
pH: Slightly acidic to neutral (pH 6.0–7.0).
Ensure pots have drainage holes; avoid overwatering; use a soil mix with good aeration.
Temperature
Prefers cool to moderate temperatures (60–75°F or 15–24°C); tolerates cooler nights; avoid extreme heat or cold.
Avoid placing near drafty windows or heat sources; maintain consistent temperatures; protect from sudden temperature fluctuations.
Fertilizing
every 4–6 weeks during growing season, none in winter
Apply fertilizer to moist soil to prevent root burn; stop fertilizing when the plant is dormant; flush soil occasionally to prevent salt buildup.
Propagation
Methods
Stem cuttings or seed; stem cuttings are faster and more reliable for home growers.
Step-by-Step Propagation Guide
- Take a 4–6 inch cutting below a leaf node.
- Remove lower leaves.
- Dip in rooting hormone.
- Plant in moist medium.
- Maintain humidity and warmth.
Best Time: Spring or early summer when the plant is actively growing.
Environment
Warm (70–75°F or 21–24°C), humid environment with indirect light.
Medium
Well-draining potting mix (e.g., perlite and peat moss blend) or vermiculite.
Hormone
Rooting hormone is recommended to improve success rates.
Timeline
Roots typically develop in 2–4 weeks; new growth may appear in 4–6 weeks.
Tools Needed
Pruning shears, rooting hormone, small pots, misting spray bottle.
Quick Tips
Use sharp, sterile tools to prevent infection; maintain consistent moisture; provide bottom heat if possible.
Pruning & Repotting
Pruning Guide
Method
Pinch back growing tips to encourage branching; cut spent flowers just above a leaf node or lateral bud.
Pruning Plan
Prune to maintain shape, encourage bushier growth, and remove spent flowers to prolong blooming.
Tools
Sharp pruning shears or scissors, clean gloves.
Checklist
Use clean tools; prune dead or damaged growth; remove spent flowers; shape as needed.
Repotting Guide
Best Season
Early spring before new growth begins.
Pot Size
Choose a pot one size larger (1–2 inches wider in diameter) than the current one.
Method
Gently remove the plant; trim any circling roots; place in a new pot with fresh, well-draining soil; water thoroughly after repotting.
Suggestions
Repot every 1–2 years or when roots outgrow the container; beneficial for maintaining vigor and preventing root-bound conditions.
Checklist
Select appropriate pot size; prepare fresh soil mix; handle roots carefully; water after repotting.
Advanced Care Tips
Watering Mastery
Watering Checklist
Check soil moisture; water deeply; ensure drainage; avoid wetting foliage.
How to Apply Water Properly
Water at the base of the plant, ensuring moisture reaches the root zone; water early in the day to minimize evaporation and fungal growth; allow excess water to drain away.
Watering Schedule Tips
Water deeply once the top inch of soil is dry; reduce frequency in winter to prevent root rot.
Soil Improvement
Add perlite or coarse sand for drainage; incorporate compost for fertility; use a cactus or succulent mix as a base.
Temperature Stress Management
Signs of Temperature Issues
Wilting, yellowing leaves, stunted growth, or bud drop in extreme heat; leaf discoloration or frost damage in cold.
Cold Stress
Low temperatures can slow growth, cause leaf discoloration, or lead to frost damage if below 50°F (10°C).
Solution: Provide frost protection in cold climates; move potted plants indoors during freezing temperatures; avoid sudden temperature drops.
Hot Stress
Excessive heat can cause wilting, leaf scorch, or reduced flowering; may lead to dehydration.
Solution: Provide partial shade during peak heat; increase watering frequency; use mulch to retain soil moisture.
Fertilizing Guide
Fertilizing Checklist
Use diluted fertilizer; apply during active growth; avoid winter feeding.
Fertilizing Method
Use a balanced, water-soluble fertilizer diluted to half strength; fertilize every 4–6 weeks during the growing season (spring and summer); avoid fertilizing in fall and winter.
Common Problems & Solutions
Toxicity Warning
Cats
Non-toxicCornflower is not considered toxic to cats. The plant is generally safe for feline consumption, though excessive ingestion may cause mild gastrointestinal upset.
⚠️ Symptoms:
⚡ Toxic If:
if ingested
Dogs
Non-toxicCornflower is not considered toxic to dogs. The plant is generally safe for canine consumption, though excessive ingestion may cause mild gastrointestinal upset.
⚠️ Symptoms:
⚡ Toxic If:
if ingested
Humans
Slightly ToxicCentaurea cyanus, commonly known as cornflower, is generally considered non-toxic to humans. However, ingestion of large quantities of seeds or roots may cause mild gastrointestinal discomfort due to the presence of certain bioactive compounds.
⚠️ Symptoms:
🌿 Toxic Parts:
⚡ Toxic If:
if eaten in large quantities
Frequently Asked Questions
Q: Is Cornflower toxic to pets?
A: No, Cornflower is non-toxic to dogs and cats.
Q: How often should Cornflower be watered?
A: Water moderately, allowing the soil to dry slightly between waterings.
Q: Does Cornflower attract wildlife?
A: Yes, it attracts bees, butterflies, and birds, making it a great addition to wildlife gardens.
Quick Reference
| Family: | Asteraceae |
| Care: | easy |
| Light: | full sun |
| Water: | every 7–10 days during activ |
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