How long should I continue to water a newly planted tree?

FAQ
Question: 

How long should I continue to water a newly planted tree?

Answer: 

The roots of trees continue to grow until the ground freezes.  If the weather is dry, continue to water newly planted trees until the soil freezes in winter.  Small trees usually require watering for 1 or 2 growing seasons.  It may be necessary to periodically water large trees for 3 or 4 years.