I find Iowa State University as a good source of information on gardening. Several times Google referred to me articles from ISU.
https://hortnews.extension.iastate.edu/spring-garden-tasks
https://hortnews.extension.iastate.edu/your-complete-guide-pruning-trees-and-shrubs
https://hortnews.extension.iastate.edu/2016/01-15/propagation.html