Tightly clustered florets form glowing lavender flower heads that float atop stiffly upright branching stems the long lasting blooms of verbena bonariensis attract clouds of bees and butterflies this perennial verbena has enjoyed a resurgence in popularity in recent years associating beautifully with grasses for a tranquil planting scheme or adding a touch of architectural style to the back of herbaceous borders this elegant perennial is at its most effective when planted in large swathes