Growth Habit: Butterfly bushes grow 2 to 10 feet tall and wide. The species versions grow the largest and produce the most flowers. New breeding has created many dwarf varieties that fit better in the landscape.
This woody shrub can die back to the ground in climates colder than USDA zone 5. In warmer areas, it regrows consistently each spring from old wood. The leaves can be thin, narrow and silver-green colored. Some varieties have green and yellow variegated leaves. The fragrant flowers form on 5- to 12-inch-long clusters in white, blue, lavender, pink, orange, purple, yellow with many intermediate shades.
Staking: Butterfly bushes grown in full sun have strong-enough stems that will hold the flower clusters upright and will not need staking. Tall varieties grown in part shade may have leggy and floppy stems that benefit from a cage of chicken wire wrapped around the plant, or staking of individual branches with a metal or wooden stake before flowering.
Watering: Butterfly bushes grow best in moist, well-drained soils. Keep the soil consistently moist all summer for best growth and flowering especially during hot, dry weather.