I notice that the water hyacinth in my main pond is not nearly as
green as those in a smaller pool that is in my waterfall stream. The
pool hyacinths are deep green and are even flowering while the main
pond hyacinths are lime green - yellow.

The pool is partly shaded by some grasses nearby but the main pond
gets full sun.

Is it possible that WH wants only partial sun?

TIA

John