Considered "sub-shrubs," bluebeard shrubs are deciduous and provide landscape color for the late summer. Along with butterflies, they attract bees (as the picture above attests to); for that reason, they're not good for swimming pool landscaping.
Bluebeard shrubs are full-sun plants that like a well-drained soil. As with similar plants that crave lots of sun and a sharp-draining soil, they can be considered drought-tolerant shrubs once established. Growers frustrated by deer incursions will be glad to hear that they are also deer-resistant shrubs.
Different cultivars are available. I grow 'Longwood Blue,' myself. While some cultivars reputedly have fragrant flowers, I don't find this true of 'Longwood Blue,' but I do find its gray-green foliage aromatic (it smells of mint). Newer leaves have a yellow-green color.
Bluebeard shrubs may reach a mature height of 3-4 feet, which is slightly greater than their eventual width. The bush is listed for planting zones 5-9, but at the northern end of this range some report above-ground die-back from the winter cold. New growth will emerge in spring, though, so that's not a problem, since buds appear on new wood (the bush may simply not become as large as it would in a warmer climate). Pruning time is late winter or early spring.
But the main selling point for bluebeard shrubs is their blue flowers. Moreover, these bushes bloom just when your landscaping could most use a floral boost: near the end of the growing season.
The flower clusters are airy, thus the alternate common name "blue mist spirea." But as is often the case with the common names of plants, that's a deceptive moniker, so don't be fooled. Bluebeard shrubs are not true spireas. This nickname apparently derives from the fact that the shape of their leaves is like those on spirea (for example, 'Neon Flash' spirea and 'Gold Mound' spirea).