Fertilizing trees in Denver
I live in a CoHousing community in NW Denver with about 20 trees. We have received proposals from several arborists to fertilize our aphid invested crabapples, our 7 ash trees (to make them stronger before they get hit with the coming emerald ash borer) and to prevent chlorosis in our beautiful maples.
Problem is we can't afford the thousands of dollars for the treatment.
-Should we test the soil first? If yes, should we test separately for the sidewalk strip where soil hasn't been fertilized and is probably heavy clay, for the trees in grass where we annually spread manure, and for the trees next to rear parking lot? We occupy 1.25 acres and were built 15 years ago in a development that was formerly Elitch Gardens Amusement Park.
Thank you for your question. You might also want to fertilize yourself and not use an arborist. Use the following link to assist you http://www.extension.colostate.edu/SEA/yard%20&%20garden/Fertilizing%20and%20Pruning.pdf
If the link does not work go to CSU Extension>Yard and garden>Tree fertilization and pruning.