In my June 2016 newsletter I responded to a question about adding plants beneath citrus trees. My response was don’t; for the sake of potential problems, including death of the citrus tree.
Since then I’ve been asked what about adding flowers beneath other tree species. Again my answer is the same – DON’T!. Why? Because the majority of tree roots are in the top 2 feet of soil due to our high water table here in Florida. Digging holes for new plants may damage them and also cause suckers from tree roots to develop. Furthermore, you also have potential problems with water. Flowers normally require more frequent watering than trees, which like citrus, can lead to disease problems. Also, while it is okay to add 3-4″ of mulch around the base of your trees, be sure to keep the mulch 6″ away from the tree trunk as it too can cause potential disease problems by staying too wet. By the way, it is a good practice to have at least a 3 foot or larger ring of mulch around your trees to reduce weed competition, and potential damage resulting from the use of weed eaters, mowers, and/or edgers.
One final thought on adding plants around the base of trees, some people have added additional soil around their tree base and added plants. This practice should also be discouraged because it can affect the oxygen uptake of the tree roots and ultimately new tree roots will most likely start growing in the added soil.
I hope this puts these issues to rest, if you have any comments or concerns, I’d love to hear from you.