Mountain Spiraea

Rosy spirea, or mountain spirea (Spiraea densiflora, accepted name Spiraea splendens), is a low little shrub carrying dense flat pink flower clusters 2-4 cm across. The small oval light green leaves soften the outline, and the whole plant looks like a pink cushion set down among the rocks.

This is a plant for a rock garden, a stony slope or a damp natural corner. The bush rises only 0.3-1 m, half the height of the Japanese spireas, and flowers later than the spring species - from June to August. It spreads from a creeping rhizome, so over time it knits the ground into one solid patch.

Key characteristics:

• What makes it special: This is a mountain species of western North America, growing at 600-3300 m, and its pink flower clusters bring in bumblebees and bees.
• Dimensions: A low, spreading shrub 0.3-1 m tall that widens gradually from a creeping rhizome.
• Hardiness: Overwinters without cover - it takes frosts down to -40 °C (USDA zone 3).
• Flowering: From June to August dense flat clusters 2-4 cm across open, woven from fine pink flowers.
• Light: Sun or light partial shade - in the wild it grows in sunlit clearings among woodland.
• Soil: Moist but well-drained soil; in the wild the species keeps to rocky mid-mountain slopes.
• Watering: Regular, moderate watering - the species is used to moist habitats.