Spiraea japonica "Walbuma"

• Type: deciduous shrub, summer-flowering spiraea
• Botanical name: Spiraea japonica 'Walbuma'
• Height and spread: 30–50 cm / 60–90 cm
• Flowering: June–July; deep pink flat heads
• Foliage: red in spring, golden yellow with red new growth in summer, coppery red in autumn
• Light: full sun (foliage greens up in part shade)
• Soil: any ordinary, moderately fertile, well-drained garden soil
• Hardiness: USDA 3–4 (RHS H6), no winter cover needed in Estonia
• Pruning: early spring, hard – flowers on current-year shoots
• Use: edgings, low hedges, rock gardens, ground cover, containers
• Size: potted plant

Planting. Japanese spiraea loves sun – only in full sun does the foliage keep its bright colour; in shade it turns greener and flowers less. Any ordinary, moderately fertile garden soil without standing water will do; lighten heavy clay with sand and compost. Dig a hole twice the width of the root ball and keep the root collar at soil level. Container plants can go in from April to October; for an edging allow 40–60 cm between plants.

Watering and feeding. In the first season water once a week, 5–10 L per plant, more often in hot spells; once established it tolerates short droughts. Feed in spring with a balanced fertiliser for flowering shrubs and once more after the first flush of bloom. A mulch of bark or compost holds moisture.

Care. Japanese spiraea flowers on the current year's shoots, so prune it in early spring (March–April), cutting all stems back to 10–30 cm above the ground. This keeps the shrub dense and the flowering generous. Remove faded flower heads to get a second flush in late summer. No winter protection is needed in Estonia: any frost-damaged tips are simply cut off in the spring prune.

Gardener's tip. 'Magic Carpet' is most colourful while growing, so give it a light trim with shears after the first flowering: you will get fresh red growth and sometimes a second flush of flowers.