Fertilizing: Before you fertilize, test the soil to see if nutrients are needed. You may harm or "burn" your tree if you apply fertilizer when it’s not needed. Soil testing kits are available at garden centers. Another option is to send a sample to the University of Minnesota – Soil Testing Laboratory, which offers a wide range of tests including fertility, pH, organic matter and soluble salts.
Contact a Tree Care Professional (PDF): Want to hire someone to do tree work or perform a tree evaluation? Contact a professional from the List of Licensed Tree Companies (PDF). These companies have met City requirements for liability insurance and training. Be wary of companies going door-to-door looking for work -- they may lack proper training and insurance. For-hire tree workers must by licensed by the City to do tree work.
University of Minnesota – Plant Disease Clinic: Does your tree show signs of a disease? You can send samples to the U of M Plant Disease Clinic, a multi-disciplinary diagnostic lab that provides testing services for fungal, bacterial, viral and other plant health conditions.