Thunberg's Meadowsweet (Spiraea thunbergii)

Thunberg's Meadowsweet

Spiraea thunbergii

Clouds of tiny white blooms soften spring landscapes. Deciduous flowering shrub; common names: Thunberg's meadowsweet, baby's breath spirea.

Full sun
1–2/week
Beginner
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Plant Needs

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Sunlight Prefers full sun for abundant blooms; tolerates partial shade, though flowering may be reduced
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Watering Water deeply when the top 5 cm of soil is dry; avoid overwatering to prevent root rot
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Temperature Cold-hardy to -20°C; tolerates mild summer heat, avoid prolonged temperatures above 35°C
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Characteristics

  • Leaf: Narrow linear to lanceolate leaves, bright green in spring/summer, turning golden yellow in autumn
  • Flower: Dense clusters of tiny, star-shaped white blooms covering slender arching stems
  • Stem: Slender, brown twiggy stems that form a cascading, rounded canopy
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Care Guide

Watering

Keep soil consistently moist during active growth; provide extra water during prolonged drought

Fertilization

Apply a balanced slow-release fertilizer once in early spring. Do not over-fertilize, as excessive nitrogen can reduce flowering

Banana Peel Compost Tea:Compost banana peels for 2–3 weeks, steep in water for 24 hours, dilute 1:20 for root drench; avoid raw peels to prevent pest infestations
Pruning
  • Prune immediately after flowering to maintain a compact, rounded shape
  • Remove dead, damaged, or crossing branches in late winter to improve airflow
  • Thin overcrowded stems to encourage new growth and abundant blooms the following spring
  • Avoid heavy pruning in late autumn, as this may remove next year's flower buds
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Toxicity

Warning: this plant may be toxic.

Pets & Humans

Pets: ASPCA-verified non-toxic to cats; no risk of poisoning from ingestion

Humans: Non-toxic to humans; no known adverse health effects from ingestion or contact

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Garden Uses & Culture

Culture: Symbolizes delicate spring beauty and gentle renewal in ornamental gardening

Usage: Ornamental garden shrub, low hedge plant, cut flower filler for spring bouquets