The Extension website says that evergreens can be planted in early fall. How late can I safely plant an evergreen this year?
Hennepin County Minnesota
If you are going to plant an evergreen, do it now. Most garden centers do not sell nor recommend planting evergreens after October 1st. They need time to get settled in and take in the large amount of moisture they need to make it through the winter. Evergreens lose moisture all winter as they do not lose their 'leaves'. You must water your evergreens until the ground freezes.Lack of moisture going into winter is one of the main reasons for failure of evergreens.