'Black Knight' Butterfly Bush 3 Gallon Potted Shrub Light Gaia Green All Purpose Fertilizer best in a sheltered Gaia Green All Purpose Fertilizer 4 4 4 is an excellent all round fertilizer for the landscape and garden The oval compound leaves do not develop any appreciable fall colour You can start seeing the clusters of flowers as early as May or June and they will last all the way until September As long as you have a sunny planting spot this flowering perennial shrub will flourish with big purple flower heads whose fragrance will attract butterflies and other pollinators like bees or hummingbirds to your landscape