Smooth Hydrangea (Hydrangea arborescens)

Smooth Hydrangea

Hydrangea arborescens

Lacy white blooms cloud the summer garden, softening edges with cottage charm. Deciduous flowering shrub; common name: Smooth Hydrangea.

Partial sun
1–2/week
Beginner
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Plant Needs

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Sunlight Prefers filtered morning sun and afternoon shade to prevent leaf scorch; tolerates full shade with reduced flowering
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Watering Keep soil consistently moist but not waterlogged; avoid allowing the root ball to dry out completely during hot summer periods
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Temperature Hardy to extreme cold temperatures; suitable for USDA zones 3–9; protect young plants from late spring frost damage
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Characteristics

  • Leaf: Simple, opposite, ovate to elliptical with serrated margins, medium green with soft fine hairs
  • Flower: Dense rounded corymbs of sterile white florets; small fertile florets are less visible
  • Stem: Upright branching, green to light brown, smooth to slightly pubescent
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Care Guide

Watering

Water deeply once weekly during dry spells; maintain even soil moisture

Fertilization

Apply diluted balanced organic fertilizer once monthly. Avoid over-fertilizing to prevent excessive foliage growth at the expense of blooms

Composted banana peel tea:Steep fully composted banana peels in water for 24 hours; dilute the mixture 1:20 before applying as a root drench to avoid nutrient burn
Pruning
  • Prune back to 30–60 cm above ground in late winter to encourage vigorous new growth and larger flower heads
  • Remove dead, damaged, or crossing branches to improve air circulation and shrub shape
  • Thin overcrowded stems in early spring to maintain a rounded, open growth habit
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Toxicity

Warning: this plant may be toxic.

Pets & Humans

Pets: ASPCA: Toxic due to cyanogenic glycosides; ingestion may cause vomiting, diarrhea, depression, and abdominal pain

Humans: Ingestion of large amounts causes mild gastrointestinal irritation, nausea, or vomiting

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Garden Uses & Culture

Culture: Symbolizes heartfelt gratitude and genuine emotion; a popular choice for cottage-style garden designs

Usage: Ornamental garden shrub; cut flower arrangements for indoor decor