Answer: Technically, you can plant container grown trees and shrubs up until the ground freezes up hard, but preferably it is best to finish your planting about 8 weeks before that if possible. Also, evergreens are better off planted in the spring.
September and October are actually excellent months to plant deciduous trees and shrubs if you can find the selection you need. There are many online and paper catalog sources for plants, selection will vary with them according to the season also.
I would suggest you check out the following resources. The first is a searchable list of suppliers, then check them out at the other two sites where many different catalogs are evaluated.
Some to consider might include
Enjoy your new home and landscaping!
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