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Shrub Library

Spirea

Spiraea japonica

Spirea is a compact, hard-working flowering shrub that tolerates Colorado's alkaline soils and temperature swings while blooming through much of the summer with minimal care.

Quick specifications

Mature Size
2–4 ft tall | 2–4 ft wide (varies by cultivar)
Growth Rate
Moderate
Form
Compact, mounded deciduous shrub
Foliage
Green, gold, or bronze depending on cultivar
Sun
Full sun preferred for best flowering and foliage color
Water
Moderate water needs once established
Soil
Tolerates a wide range of soils if well-drained
Bloom
Pink, white, or red (spring–early summer)
Lifespan
30–40+ years under Front Range conditions
Hardiness
Excellent cold hardiness and heat tolerance
Native Status
Non-native

Overview

Spirea is a small, mounded deciduous shrub used heavily in foundation and mass plantings.

Cultivars vary widely in foliage color, from gold and lime to blue-green, giving season-long interest beyond bloom.

Identification

  • Pink spirea flower clusters in early summer

    Flower

  • White-flowering spirea showing compact, mounded form

    Mature form

Colorado Suitability

Cold hardy and tolerant of late spring frosts.

Handles alkaline Front Range soils.

Compact size suits tight residential beds.

Planting Considerations

  • Full sun produces the heaviest bloom and best foliage color.
  • Space for mature width to preserve the mounded form.
  • Mulch to stabilize soil moisture.

Care

  • Water moderately and consistently through summer heat.
  • Light spring fertilization is sufficient.

Pruning

  • Shear lightly after the first bloom to encourage rebloom.
  • Cut back by one-third in late winter to maintain density.
  • Renewal-prune woody, open plants hard in early spring.

Best Use Scenarios

  • Foundation plantings and mass beds
  • Low hedges and borders
  • Commercial landscapes and HOAs
  • Low-maintenance flowering shrub plantings

Common Problems

  • Powdery mildew in crowded plantings.
  • Aphids on new growth.
  • Leggy, open habit when never pruned.

Related Diseases

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