Costmary (Tanacetum balsamita)

Costmary

Tanacetum balsamita

Aromatic foliage carries herbaceous warmth, a versatile culinary and medicinal herb. Perennial herb; common names: costmary, alecost.

Full sun
1–2/week
Beginner
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Plant Needs

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Sunlight Full sun to partial shade; tolerates mild afternoon shade in hot climates to prevent leaf scorch
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Watering Water deeply when the top 2–3 cm of soil is dry; avoid overwatering to prevent root rot
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Temperature Hardy to -15°C; thrives in cool to temperate conditions; protect from prolonged heat above 32°C
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Characteristics

  • Leaf: Long, lance-shaped leaves with serrated margins; glossy green, aromatic when crushed
  • Flower: Clusters of small, creamy-white daisy-like composite flowers
  • Stem: Erect, rigid stems with fine pubescence
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Care Guide

Watering

Keep soil consistently moist but not waterlogged

Fertilization

Apply balanced diluted organic feed once monthly. Use low-nitrogen feed to promote foliage aroma and compact growth

Composted banana peel tea:Soak fully composted banana peels in water for 24 hours, dilute 1:20 before applying to soil; avoid raw peels to prevent pest infestations
Pruning
  • Pinch back young stems in early spring to encourage bushy, compact growth
  • Deadhead spent flowers to prolong the blooming period and redirect energy to foliage production
  • Cut stems back to 10 cm above soil after the first frost to prepare for winter dormancy
  • Remove yellowing or damaged foliage to maintain plant health and appearance
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Toxicity

Warning: this plant may be toxic.

Pets & Humans

Pets: ASPCA: Non-toxic to cats; no known adverse effects from ingestion or contact

Humans: Non-toxic to humans; safe for culinary and topical use in moderate amounts

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Garden Uses & Culture

Culture: Used in medieval herb gardens as a medicinal and culinary herb; historically associated with remembrance and love tokens

Usage: Culinary herb for flavoring soups, salads, and herbal teas; aromatic foliage for potpourri and sachets; mild topical use for skin soothing