Fragrant, deep blue flowers with golden throats are massed on long spikes at the end of each branch from late July up to frost on this half-hardy shrub that is usually killed back to ground level each winter. Plant this butterfly bush in full sun and in moist, well-drained soil in a location in your garden from which you can observe the droves of butterflies and hummingbirds attracted to the honey-scented, nectar-filled flowers.