In order to ensure lots of bright purple flowers absolutely overloading the branches of your Catawba tree, we recommend a regular feeding routine with a tree fertilizer. This way your tree does not need to worry about reserving resources and holding back from its bloom cycle. We recommend using an organic and well-balanced fertilizer every other month from April to August, such as Espoma Tree-tone. You can also use a starter fertilizer when first planting, in order to introduce nutrients and healthy elements to the soil. Espoma Bio-tone Starter Plus is a great way to help give your Catawba Crape Mytle a head start while it is establishing its root system.