Sea Salt Makes Plants Healthy(?)

by BonsaiMary
(Miami, FL)

I almost forgot one of my all time favorite bonsai myths!

The first time I heard the recommendation to use sea salt in the water for certain bonsai trees, I was a little surprised. Someone brought a beautiful buttonwood to show me and the leaves seems to extraordinarily fat. I asked if it had been recently purchased; as this is what recently collected leaves often look like. (Straight out of the Florida Keys.)

"No, I purposely make them that way with sea salt, just like they get from the ocean".

I explained that the whole idea was for the plant to exude the salt through the leaves not to keep it. However, I'm not sure I convinced anyone.

Years later the same subject appeared on the internet regarding a Pemphis in the Philippines.

"Salt water will really help for the health."

I gave in, I went online. "OK guys, I'm not trying to be difficult, however using sea salt for shoreline trees is a bonsai myth. I've researched the subject ... it won't hurt but it does not make the tree healthier." My comments were not well received.

When I reach a controversial conclusion, I try to back it up with justifiable data. To verify my statements, I contacted Dr. Nina Shiskoff at the U.S. Department of Agriculture.

Her reply follows:

"Well, first of all, the leaf thickening will only occur in salt-tolerant species. I wouldn't try to do this with a plant that isn't adapted to brackish water. For plants that are able to tolerate brackish conditions, brackish conditions don't make them healthier, they simply tolerate it better than plants that aren't adapted. Therefore, they can grow where other plants can't ... Most plants that can grow well in extreme environments can also grow perfectly well in good conditions.

So my feeling would be: if you want the thick leaves, go ahead and add a little salt. But Mary is right: the tree doesn't need salt to be healthy."