Spiraea japonica
Summer spirea
Common names: Japanese spirea, Rose spirea
At a glance
- Light
- Full sun
- Hardiness
- Hardy
- Pruning
- Feb–Mar
- Flowering
- Jun–Aug
Photo: Paul Hermans · CC BY-SA 3.0 · Source
This description was machine-translated.
Description
The Summer spirea (Spiraea japonica) is a compact, summer‑blooming shrub that produces delicate pink panicles in dense clusters from June to August. Unlike spring spirea, it blooms on this year’s wood, so it can be heavily pruned in early spring without jeopardising the flowers. It typically grows to 60 to 120 cm tall and is well suited as a border plant, in groupings, or as a low hedge. Bees and butterflies are attracted to its blooms, making it a valuable component of insect‑friendly gardens. Cultivars such as ‘Little Princess’ and ‘Goldflame’ remain especially compact and are suitable for smaller beds.
Care instructions
Plant the Summer spirea in a sunny to slightly shaded location with well‑drained, moderately moist soil. Prune annually in early spring (late February to mid‑March, weeks 9 to 11), cutting back about one‑third of the growth to encourage dense foliage and richer flowering. Remove spent panicles in summer to often stimulate a second, weaker flush. Water newly planted specimens regularly; established shrubs tolerate occasional watering during dry periods. A mulch layer of leaf or bark mulch keeps the root zone moist and suppresses competing vegetation.
The care notes were machine-translated from German.
Garden year
FloweringJun–Aug
Soil & site
Soil pH
Soil type
well-drained, humus-rich, nutrient-rich, loamy
Japanese spiraea likes well-drained, humus-rich garden soil and tolerates both slightly acidic and neutral soils well. You should avoid waterlogging, otherwise the fine roots rot. On lean, sandy sites, a dose of compost at planting helps the shrub establish quickly.
Feeding
Medium feeder
Months
Mar, May
A dose of mature compost in early spring is usually enough for Japanese spiraea for the whole season. If you want stronger new growth and more flowers, add some horn shavings or rotted manure around the root zone in mid-May. Straight after the spring pruning, the shrub welcomes a thin mulch layer that releases nutrients slowly.
Pruning
Because Japanese spiraea flowers on new wood, it is best cut back hard in late winter or very early spring. Cutting back to 15 to 20 cm above the ground encourages dense, bushy growth and plenty of flowers in summer. You can also remove spent panicles as you go, which extends the flowering into late summer.
Overwintering
Japanese spiraea is hardy in our latitudes and needs no special protection in mild areas. In very cold regions or with young plants, a mulch layer of leaves or bark mulch over the roots helps. Place container plants in a sheltered spot against a house wall and wrap the pot so that the roots do not freeze through.
Propagation
Methods
- Cuttings
- Division
The easiest way to propagate Japanese spiraea is by semi-ripe cuttings, which you take in summer after flowering and insert in a well-drained substrate. New roots form within a few weeks in a sheltered, bright spot. With older, spreading shrubs you can also divide a root ball in early spring and replant the pieces straight away. Sowing is possible, but it takes much longer to the first flower and does not always give offspring that come true.
Companion planting
Companion planting is partly traditional gardening lore. Where the reason is known, it is given.
Some of these explanations were machine-translated.
For your garden
Grow Summer spirea yourself
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