How to Prune spiraea 'Grefsheim'?
Cut flowered growth back to strong young shoots below, removing up to a fifth of old stems near the base each year. Prune immediately after flowering.

spiraea 'Grefsheim' · Spiraea × cinerea 'Grefsheim'
Easy to grow in most moist soils, tolerant of all but the most extreme conditions. Especially suitable for mixed borders
Cut flowered growth back to strong young shoots below, removing up to a fifth of old stems near the base each year. Prune immediately after flowering.