Pyrethrum

tanacetum corymbosum

Also known as: ["Pyrethrum daisy","Corymbiferous tansy"]

Family: Asteraceae Genus: Tanacetum Category: Flowers

Overview

A perennial herbaceous plant with daisy-like flowers, native to Europe and Asia.

Benefits & Perks

["long-flowering","wildlife attractant (bees, butterflies, birds)","disease resistant"]

Botanical Classification

Phylum: Magnoliophyta
Class: Magnoliopsida
Order: Asterales
Family: Asteraceae
Genus: Tanacetum
Botanical Name: Tanacetum corymbosum

Plant Characteristics

Basic Information
  • Category: Flowers
  • Suitable Location: border plantings, rock gardens, or containers in temperate climates
  • Suitable For:
    Beginners Outdoor Landscapers Wildlife Supporters
  • Is Weed: No
  • Allergenicity: moderate
Environmental Needs
  • Climate: {"temperatureRange":"5–30°C"}
  • Hardiness: {"zones":"4–9"}
  • Misting: rarely required, only if grown in very dry indoor conditions
  • Drainage: Fast-draining to prevent waterlogging.
  • Soil Type: Well-draining, loamy soil with added organic matter; can tolerate average garden soil.
Maintenance Level
  • Maintenance Level: moderate
  • Toughness Level: moderate
  • Pruning Frequency: Deadhead spent flowers regularly during blooming season; shape prune in early spring before new growth begins.
  • Pruning Intensity: Light to moderate; avoid heavy pruning unless necessary to control size or rejuvenate old plants.
Care Details

Ideal Sunlight Coverage:
Full sun (6–8 hours of direct sunlight daily); tolerates partial shade in hot climates.

Sunlight Tolerance Tips:
Acclimate plants gradually to intense sunlight; protect from harsh afternoon sun in hot regions; ensure good air circulation to prevent fungal issues.

Warning Signs: Yellowing leaves, root rot, or stunted growth indicate poor soil conditions or improper watering.

Care Requirements

Care Difficulty
easy

moderate

Sunlight

full sun to partial shade

Rotate plant for even light exposure; use sheer curtains to filter intense sun; avoid placing in shaded corners.

Watering

every 7–10 days, allowing soil to dry between waterings

Water thoroughly until it drains from the bottom, allow soil to dry slightly between waterings, and avoid overwatering to prevent root rot.

Soil

well-draining, loamy soil with moderate organic content

pH: Slightly acidic to neutral (pH 6.0–7.0).

Avoid heavy clay soils; amend with organic matter; ensure good drainage to prevent root rot.

Temperature

Prefers cool to moderate temperatures (60–75°F or 15–24°C); can tolerate cooler nights down to 50°F (10°C).

Avoid sudden temperature fluctuations; protect from frost; ensure good air circulation in hot weather.

Fertilizing

every 4–6 weeks during active growth with balanced liquid fertilizer

Apply fertilizer after watering to prevent root burn; stop feeding in late autumn to allow dormancy.

Propagation

Methods

Stem cuttings or division; stem cuttings are more common for home growers.

Step-by-Step Propagation Guide
  1. Take 4–6 inch cuttings.
  2. Remove lower leaves.
  3. Dip in rooting hormone.
  4. Plant in medium.
  5. Keep moist and warm.

Best Time: Early spring or late summer when the plant is actively growing.

Environment

Warm, humid environment with indirect light; maintain consistent moisture.

Medium

Well-draining potting mix with perlite or sand; can also root in water initially.

Hormone

Rooting hormone is recommended to improve success rates.

Timeline

Roots typically form in 3–6 weeks; new growth may appear in 2–3 months.

Tools Needed

Pruning shears, rooting hormone, small pots, well-draining medium.

Quick Tips

Use healthy, non-flowering stems; maintain high humidity with a plastic cover; avoid direct sunlight.

Pruning & Repotting

Pruning Guide
Method

Pinch back tips for bushier growth; cut stems just above a leaf node or bud.

Pruning Plan

Prune to maintain shape, encourage bushier growth, and remove spent flowers to promote reblooming.

Tools

Sharp bypass pruners, clean scissors, gloves.

Checklist

Use clean tools; prune dead or damaged stems; remove spent flowers; shape as needed.

Repotting Guide
Best Season

Early spring before active growth begins.

Pot Size

Increase pot size by 1–2 inches in diameter; avoid oversized pots.

Method

Remove plant gently; trim any circling roots; place in a slightly larger pot with fresh, well-draining soil; water thoroughly.

Suggestions

Repot every 2–3 years or when roots fill the container; beneficial for container-grown plants to refresh soil and provide space.

Checklist

Choose 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 leaves.

How to Apply Water Properly

Water directly at the root zone, ensuring even moisture distribution without wetting foliage; water early in the morning to minimize evaporation and allow leaves to dry.

Pro Tip: Use a watering can with a narrow spout to target the soil directly at the base of the plant.
Watering Schedule Tips

Water deeply once the top inch of soil feels dry, typically every 7–10 days during active growth, reducing frequency in winter to every 2–3 weeks.

Soil Improvement

Add compost or well-rotted manure for fertility; mix in perlite or sand for drainage; ensure good aeration.

Temperature Stress Management
Signs of Temperature Issues

Wilting, yellowing leaves, stunted growth, or bud drop in extreme heat or cold.

Cold Stress

Slows growth, may cause leaf discoloration, and can lead to frost damage in freezing conditions.

Solution: Provide frost protection in winter, such as mulching or moving potted plants indoors; avoid placing near drafty windows or doors.

Hot Stress

Leaves may wilt, curl, or scorch; flowering may be reduced in excessive heat.

Solution: Provide afternoon shade, increase watering frequency, and 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 every 4–6 weeks during the growing season (spring to early fall); avoid fertilizing in winter.

Common Problems & Solutions

Yellowing leaves in Tanacetum corymbosum may indicate nutrient deficiencies, such as nitrogen or iron, improper watering, or pest infestations like spider mites or aphids. It can also be a sign of root rot or fungal infections.

Wilting in Tanacetum corymbosum is often caused by water stress, either due to overwatering leading to root rot or underwatering causing dehydration. It may also result from pest infestations or severe disease affecting the vascular system.

Leaf spots on Tanacetum corymbosum are commonly caused by fungal pathogens like Cercospora or Alternaria, leading to defoliation and reduced photosynthetic efficiency. Severe infections can weaken the plant and reduce its vigor.

Rotting in Tanacetum corymbosum is typically associated with root or stem rot, caused by overwatering or fungal pathogens such as Fusarium or Pythium. This can lead to plant decline and death if not addressed promptly.

Toxicity Warning

Cats
Slightly Toxic

Cats are sensitive to pyrrolizidine alkaloids, which can cause liver damage upon ingestion in large quantities. The toxicity is cumulative and may lead to chronic liver disease.

⚠️ Symptoms:
vomiting loss of appetite lethargy jaundice
🌿 Toxic Parts:
leaves flowers seeds
⚡ Toxic If:

if eaten in large quantities

Ensure plants are inaccessible to cats. Seek veterinary attention if ingestion is suspected.
Dogs
Slightly Toxic

The pyrrolizidine alkaloids in Tanacetum corymbosum can lead to liver toxicity in dogs if consumed in large amounts. Chronic exposure may result in severe liver dysfunction.

⚠️ Symptoms:
vomiting diarrhea lethargy jaundice
🌿 Toxic Parts:
leaves flowers seeds
⚡ Toxic If:

if eaten in large quantities

Keep plants out of reach of pets. Monitor pets for any signs of ingestion.
Humans
Slightly Toxic

Tanacetum corymbosum contains pyrrolizidine alkaloids which can cause liver damage if ingested in significant amounts over time. The effects are cumulative and may not be immediately apparent.

⚠️ Symptoms:
nausea vomiting abdominal pain liver damage
🌿 Toxic Parts:
leaves flowers seeds
⚡ Toxic If:

if eaten in large quantities

Avoid ingestion. Use gloves when handling to prevent skin contact with sap.
Important: Keep this plant out of reach of children and pets. If ingestion occurs, contact poison control or veterinary services immediately.

Frequently Asked Questions

Q: Is Tanacetum corymbosum toxic to pets?

A: It is mildly toxic to dogs and cats.

Q: How often should I water Tanacetum corymbosum?

A: Water moderately, allowing the soil to dry slightly between waterings.

Q: Does Tanacetum corymbosum attract wildlife?

A: Yes, it attracts bees, butterflies, and birds due to its nectar-rich flowers.

Quick Reference
Family: Asteraceae
Care: easy
Light: full sun to partial shade
Water: every 7–10 days, allowing so
Suitable For: ["beginners","outdoor landscapers","wildlife supporters (attracts bees, butterflies, birds)"]
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