Ask Mr. Smarty Plants

We are in a small dilemma over your question. The Lady Bird Johnson Wildflower Center is committed to the care, protection and propagation of plants native not only to North America but to the area in which it is being grown. St. Croix is in the US Virgin Islands, which is an unincorporated territory of the United States, but not North America. Myrciaria floribunda (guavaberry tree) is native to the Caribbean but not to North America, so we have nothing on it in our Native Plant Database. However, your question is a basic one, common to many gardeners, of how and whether to attempt the transplanting of a large, mature tree, so we'll see what we can come up with.

Since we know nothing about this tree, we did some research and learned that it is a fairly rare tree, native to the Caribbean, Mexico, Central and South America. It has been introduced into the Phillipines, Hawaii and Florida. Most of the literature we found had more to say about the berries, from which a popular liquor is made and featured in Christmas traditions. The berries are apparently not easy to harvest, because it is a very stout tree and may grow from 33 to 60 feet high and resists shaking to dislodge the fruit.  About the most informative article we found was from nutritiousfruit.com Guavaberries. From that article, we excerpted this statement:

"It is a temperamental tree often not bearing fruit due to high winds and insect infestation. Under favorable conditions the trees can bear fruit during various times of the year. For tropical plant enthusiasts, it can be grown indoors. As an indoor shrub it can potentially reach a height of about six feet."

Now we come to whether or not you can, or should, attempt to transplant this tree. We were unable to find anything on what kind of root system this tree has, other than that it is a member of the Myricaceae or bayberry family. There are a number of members of that family native to North America, including Morella cerifera (wax myrtle). They are usually purchased as small shrubs in the nurseries, and transplanted immediately, so we still don't know how the family feels about transplanting a large tree. 

Back to the basics, how do you transplant a large tree? We found two articles with pretty comprehensive information, Popular Mechanics Guide to Planting Mature Trees and, from North Dakota State University Extension Transplanting Trees and Shrubs which has a section on large trees. If you can, we would suggest you consult a professional arborist on the possibilities and consequences of this move. As large as the tree is, it would appear you are going to need expensive equipment and quite a few manhours to accomplish it, and the tree still might die. Without knowing your explicit reasons for wanting to move the tree, that is about the best we can do.