Posted by Eivind Nash on July 9, 2005

Q: Why do pines need to be transplanted in either early spring or late fall? What is wrong with transplanting a 7'-8' White Pine tree in mid July (Minnesota)?

A: Good question, as on the surface it doesn't make sense that summer would be a poor time. But there are some good reasons. First though, if your tree is currently in a container (I'm assuming that your 7-8' tree is not, however) it can be planted anytime in the spring, summer or fall. Container-grown trees can be popped into the ground most of the year because ALL of their roots are intact and the tree isn't stressed with any root reduction when moved.

BUT planting a tree that has been lifted from the ground and not from a nursery pot means it has had its roots severely reduced and this is the problem/issue. Keep in mind that the hair roots out at the ends of the roots are the ones that "do the work" of absorbing nutrients and water, not the thick roots near the base of the trunk. The evergreens (pines, spruce, firs) have two periods during the warmer months when they put out new root growth - spring and again in the fall. If you plant your tree during these times, you are reasonably assured that your tree will add new root growth that is essential to keep it going through the summer or through the winter (evergreens transpire in the winter so must be able to replenish their water even then). IF, however, you transplant your pine in the summer your tree gets a double whammy! One, the tree is not at the right time of the year to quickly put out new "feeder" roots and two, the summer heat/sun will put greater water demands on the tree than it can handle - your success rate will plummet. Hope this helps answer your question. Thanks for asking.

John Wiessinger ( July 10, 2005)