With a long history of garden use, Spiraea make an excellent addition to the garden. Sometimes called ‘meadowsweet’ or the ‘may bush’, they have masses of flowers in spring and grow well in full sun.
With over 70 species, mostly from China and nearby countries, you will find dozens of varieties available for sale with flower colors ranging from pure white through to pinks and reds. Spiraea ‘Snow storm’ is a white flowering cultivar, good green foliage and large flowers.
The low growing spires ‘Carpet Magic’ has deep pink flowers, lime green foliage, and will reach around 1 1/2ft, an excellent ground cover plant.
Spiraea cantoniensis ‘Lanceata’ are a hardy group of small deciduous shrubs sometimes referred to as the ‘May Bush’ . Spiraea thunbergii is known as meadowsweet the pink flowering Spiraea japonica is the Japanese spiraea.
All spiraea grow well in a humus rich moist but well drained soil. They do require full sun, although light afternoon shade is suitable.
Mulch around plants to maintain a cool root run
Additional water during hot dry periods in summer
Deadhead after flowering to tidy up and promote a second flush of flowers
Looking at Trees and Shrubs in more detail
- Spiraea nipponica ‘Snowmound’ – Brilliant white flowers
- Spiraea japonica ‘Goldmound’ – Lime green foliage
- Spiraea x bumalda ‘Crispa’ – Deep pink flowers with crinkled foliage
- Spiraea x vanhouttei – Also known as ‘Bridalwreath’. Masses of white flowers.
- Spirea japonica ‘Magic Carpet’ – Low growing pale green foliage and mid pink to red flowers.
Two schools of thought on how to prune Spiraea, and it does depend on the zone you live in.
If you live in an area subject to heavy frosts it is best to leave pruning until spring, after the frosts. In this case you prune back 1/3 of the bush at this time.
Removing any dead or damaged wood and some of the thin spindly canes. Then you can cut back to buds on the stems.
This method allows you to remove frost damaged growth and growing tips.
The second theory is to prune after flowering, just shape the bush to what you want.
However, the Japanese and Spiraea x bumalda hybrids are best lightly pruned in spring before flowering. Any major cutting back is always done after flowering.
Problems – Diseases
Spirea are available for sale from the following specialist nurseries.