How to grow cumquats in Canberra and what to do with them | The Canberra Times

Fortunately, ants are relatively easily kept away from citrus trees and single-trunked rose trees. To stop ants climbing up the trunk you can buy commercial ‘tree taping oil’ barriers or make your own from something smooth like wide black tape wrapped around the trunk and more than half of something sticky like Vaseline. Ants will not be able to hold on to the slippery strip, and those that do will be stuck in the jelly. Do not apply Vaseline directly to the bark as it can damage it, and replace the tape annually so it does not rattle the tree as the trunk grows. There are many old gardening recipes that involve mixing drippings with various harmful substances to prevent ants from getting any closer. They probably work, but they’re not safe experiments for the backyard.