3 to 4 ft.
2 to 3 ft.
species is native to Himalayas and mountians of east Asia
USDA zones 5-8
hardy to 8,500 ft.
Dark Knight spirea is one of the easiest small shrubs to grow in a low water landscape. Throughout spring and early summer, it grows as a compact mound of upright branches covered with grey-green linear leaves. In late summer, dark blue flower spikes cover the shrub.
The flower spikes mature into tan seedheads that persist throughout the winter, capturing snow during winter storms. It can be an excellent, all-purpose, tidy low water shrub.
Dark Knight spirea has been an excellent plant at the Xeriscape Demonstration Garden. It's tidy compact form and reliable flower production make it adaptable to many landscapes. It's flowers are a deeper blue than blue mist spirea, plus the plant itself is smaller.
The flowers attract bees, so make sure you plant it in an appropriate location.
Cut off the old flower stalks in late winter by removing about 6-12 inches of the outer branches. If the shrub needs rejuvenation, cut the stems back to ground level before new growth begins in spring.