Birthday Cake® Butterfly Bush

Birthday Cake® Butterfly Bush is hardy in USDA zones 5 to 9 and performs best in full sun with average, well-drained soil. Good drainage matters far more than rich soil for this shrub, which dislikes wet feet, especially in winter.

Planting

1. Choose a site in full sun with well-drained soil; six or more hours of direct light gives the strongest bloom and tidiest habit.
2. Dig a hole twice as wide as the root ball and just as deep, loosening the surrounding soil so young roots can spread.
3. Set the plant so the top of the root ball sits level with the surrounding soil; avoid planting too deep.
4. Backfill with the native soil, firm gently to remove air pockets, and water in thoroughly to settle the roots.
5. Apply a 2 to 3 inch layer of mulch over the root zone to conserve moisture, keeping it pulled back a few inches from the base of the stems.

Care & maintenance

• Water. Water regularly the first season to establish a deep root system. Once established it is quite drought tolerant; water during extended dry spells but never let it sit in soggy soil.
• Feed. Light feeders by nature. A single application of balanced, slow-release shrub fertilizer in early spring is plenty. Avoid over-feeding, which produces lush leaves at the expense of flowers.
• Light. Full sun is essential. In too much shade the plant grows leggy and blooms sparsely.
• Prune. Butterfly bush blooms on NEW wood, so prune in late winter or early spring before growth begins. Cut the stems back hard, to roughly 12 inches from the ground, to encourage vigorous new shoots and abundant flowering. Do not prune in fall.
• Mulch & winter care. Maintain mulch year-round to protect roots and retain moisture. In the colder end of its range, leave the previous season's stems standing through winter and wait to cut back until spring growth shows.
• Pests & disease. Generally trouble-free. Ensure good drainage to prevent root rot, and provide air circulation to discourage occasional spider mites in hot, dry conditions.
• Bloom tips. Removing spent flower spikes through the season keeps the plant looking fresh and encourages continued blooming into fall.

When does it bloom and how long?

Expect flowers from summer well into fall. Because it blooms on new growth, the display is long and continuous, and removing faded spikes keeps fresh blooms coming through the warm months.

Why isn't my butterfly bush blooming?

The most common causes are too little sun, pruning at the wrong time, or over-feeding. Butterfly bush needs full sun and blooms on new wood, so it should be cut back in late winter or early spring, not fall. Heavy nitrogen fertilizer also pushes leafy growth instead of flowers, so feed lightly.

When and how should I prune it?

Prune in late winter or early spring before new growth starts. Cut the stems back hard, to about 12 inches from the ground. This hard pruning triggers strong new shoots and the most abundant flowering. Since it flowers on new wood, this timing will not cost you any blooms.

Does it grow in sun or shade?

Full sun. It needs at least six hours of direct light daily for dense growth and heavy bloom. In shade it becomes leggy and flowers poorly.

Is it deer resistant and good for pollinators?

Yes on both counts. The aromatic foliage means deer usually leave it alone, while the nectar-rich, lightly fragrant spires are a powerful draw for butterflies, bees, and hummingbirds, making it a true centerpiece for a pollinator garden.

Can I grow it in a container or as a hedge?

Both work well. Its compact 4 to 5 foot height suits a large, well-drained container on a sunny patio, and planted in a row it makes a free-flowering informal low hedge. In containers, use a well-draining mix and never let the pot stay waterlogged.