Springtime Planting B&B and Bare root Trees
Fall (Autumn) is generally the best time to plant B&B trees due to both the condition of the soil and the dormant state of the tree. Springtime is the second best time.
In the fall before the first freeze, soils are generally still warm enough to promote root growth. And while the trees or plants may be dormant, they will still promote roots until the soil temperature gets down to just above freezing. This gives Fall planted trees a wonderful head start in the Spring since they already have established roots ready to feed.
Springtime is the next optimal time to plant B&B trees since the tree is still dormant and there's less chance of shock and injury. However, unlike the soil in the fall, springtime soils are still cold or frozen. And even if the soil does thaw in time to plant early, it will still be cold and root growth will be slow.
While I generally recommend that all trees be staked for a short period regardless of season, Staking springtime planted trees is a must. There are absolutely no roots to support the tree and protect it from strong winds. And if a root ball is allowed to continually move or fall, the small hair roots that are trying to become established will continue to tear. It could possibly kill the tree or stunt its growth.
Once spring planted trees have made it through the strong winds, keep the staking period as short as possible. It's best to let the trees start standing on their own as soon as possible. The roots will start to spread out, thicken, and become established.