Blue Flowering Butterfly Bush

About Butterfly Bushes

• Butterfly bush is a fast-growing, prolific bloomer that is easy to grow and maintain. It grows in U.S. Department of Agriculture plant hardiness zones 5 through 9. The plant can be counted on to produce masses of aromatic flower spikes through summer and fall, dying back to the ground and faithfully returning the following season in colder regions. Mature plants typically reach a height of 6 to 10 feet with an equal spread. In some areas, butterfly bush is considered invasive and some states ban its sale.

Blue Cultivars

• The “Petite Indigo” cultivar is a compact butterfly bush that produces lilac-blue flowers and grows to only 5 feet in height and spread. “Lockinch” reaches up to 10 feet in height and spread and produces darker violet-blue flowers. A notable feature “Lockinch” is its silvery-gray foliage, a characteristic shared with “Nanho Blue,” which also produces sweetly scented, deep violet-blue flowers.

Growing Butterfly Bush

• Give butterfly bush a site in full sun with well-draining soil enhanced with organic material. Mulching deters weeds while improving moisture retention and is particularly beneficial in northern climates. Watering generally isn’t necessary except during periods of drought or hot weather. Avoid fertilizing, which promotes leaf growth over flower production. You can expect flower spikes to appear on first-year butterfly bush plants, with repeat blooms if you remove spent flowers.

Winter Care

• The last blue blooms will begin to fade in late fall to early frost, depending on where you live. In warmer climates, the leaves will remain but provide little interest because they tend to lose color. Butterfly bush shrubs typically becomes small trees in warmer climates. They may show signs of peeling bark but this is perfectly normal. In colder climates, the plant dies back to the ground and remains dormant into late spring. In any climate, plants should be mulched for winter and pruned aggressively each spring to encourage flowering from new wood.