Threelobe Spiraea (Spiraea trilobata)

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Sunlight Full sun to partial shade; produces more abundant blooms in full sun conditions

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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 Extremely cold-hardy; tolerates summer heat with consistent soil moisture

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Leaf: Three-lobed, ovate to rounded, serrated margins, bright green turning yellow in fall
Flower: Dense flat-topped clusters of tiny white, five-petaled blooms
Stem: Slender, brownish-green stems that become woody with age

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Watering

Keep soil consistently moist during active growth

Fertilization

Apply balanced slow-release fertilizer once at bud break. Do not fertilize in late fall to prevent tender new growth

Eggshell powder topdress：Crush dried eggshells into fine powder; sprinkle lightly on soil surface; water in to release calcium gradually

Pruning

Prune immediately after flowering to encourage new growth and maintain compact shape
Remove dead, damaged, or crossing stems in late winter
Thin overcrowded branches to improve air circulation and light penetration

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Warning: this plant may be toxic.

Pets & Humans

Pets: ASPCA: Non-toxic to cats

Humans: No known toxicity to humans

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Culture: N/A

Usage: Ornamental garden shrub, border plant, mass planting