Check out the Dyna-Gro company in California. I assume they have a Web site.
They put out a product called Pro-TeKt, which is potassium silicate. It
purports to increase the silicon content of those plants which can use it,
making them more disease & wind resistant. I'm sure they have done a lot of
research on the natural silicon content of various plants and would be happy to
help you.
Iris,
Central NY, Zone 5a, Sunset Zone 40
"If we see light at the end of the tunnel, It's the light of the oncoming
train."
Robert Lowell (1917-1977)