As Ed Trout referred to Bonsai Mary as his teacher, I have to ditto that.
She is absolutely correct about the salt used for buttonwood. Dr. Nina Shiskoff is on the money. I would like to add a little something to this thread, how plants react to salt.
The liquid fertilizers we use are salts, and in solution they have a salt value or concentration. The liquid inside the cells of roots have salts and solutes.
Osmosis is the phenomenon of water moving across root cell membrane into a solution of higher salt concentration. As long as the concentration of the soil solution is lower than the salt concentration of the root cell, the soil solution with its dissolved salts (nutrients and minerals) will be carried into the root cell and utilized.
Backward osmosis: If the fertilizer has a higher concentration of salt than the salt concentration in the root cell, the water will move out of the root cell and into the soil solution, thus dehydrating the root cell. This is a backward osmosis for the plant, and the effects are salt or fertilizer 'burn'.
In extreme cases it will cause fatal dehydration. In milder cases of salt poisoning only the tips of leaves will be affected. Usually they will turn yellow then brown.
So even with salt tolerant plants, an excess of salt will be detrimental to the tree. Salt water with no nutrients only makes fat leaves.
Why would you want fat leaves on a buttonwood?
Patrick Giacobbe
