Mongo' Petite Indigo® Butterfly Bush

Mongo, marketed as Petite Indigo®, is a deciduous butterfly bush with slender, light-blue flower panicles in summer and autumn. The [Royal Horticultural Society profile](https://www.rhs.org.uk/plants/85196/buddleja-davidii-nanho-petite-indigo/details) lists ‘Mongo’ as a synonym of ‘Nanho Petite Indigo’ and gives a mature range of 1.5–2.5 m tall and wide. ## Flowers and placement The RHS profile describes narrow lance-shaped leaves and slender, cylindrical clusters of light-blue flowers. It recommends full sun and well-drained soil. The 1.5–2.5 m size range reflects the RHS profile; plants may vary with climate, pruning, and growing conditions. Buddleja davidii blooms on new growth. [North Carolina State Extension](https://plants.ces.ncsu.edu/plants/buddleja-davidii/) recommends early-spring pruning to control growth and encourage flowering. In regions where butterfly bush self-seeds or naturalizes, choose a suitable sterile cultivar or a native alternative. ## Maintenance Water during establishment and avoid persistently wet soil. Prune in early spring, removing winter-damaged growth and shaping the shrub. Deadhead if reducing seed formation is important, and follow local guidance where butterfly bush is invasive.