We planted a burning bush from Hartke last year. It is just starting to bloom again. When should we start watering it and how often? Also, when should we start watering flower beds containing perennials.

Keep the burning bush and water twice weekly. They are a hardy plant and not invasive.

Don't water the burning bush. Dig it up and get rid of it. It's an invasive plant that will spread and damage the environment! https://pages.wustl.edu/mnh/invasive-plants-missouri Please landscape using native plants; our environment needs them. Also, they need very little care, like watering, once they're established. They're designed for our climate, etc.