Monday, December 7, 2015

Orange Trees with Vigorous Shoots

My neighbor recently asked this question:
"I have an older orange tree in my front yard. One of the branches is very vigorous, has large thorns on it, and the fruit is very sour.  Why is this branch different from the rest of the tree?" 

This is a fairly common problem in oranges and other sweet citrus fruit. The vigorous shoot, or branch, originates from the rootstock, that is, below the original graft or budunion. This branch, therefore, is not genetically part of the grafted orange variety. 

Rootstocks are chosen because they possess resistance to disease or some other cultural quality desired by the grower. The fruit borne from the rootstock, although a citrus species, is often sour, bitter and with little juice. Occasionally a bud will break from the rootstock, develop into a branch and grow up through the tree. Eventually this branch can set fruit, but as noted, usually of inferior quality. These sprouts or branches should be cut out. Since they are usually more vigorous than the grafted portion of the tree, they could eventually dominate the entire tree if not removed.