Ours yellowed for the first time this year. It turned out to be lack of
iron. We checked a variety of factors. HOWEVER, where the koi ate the
roots, the plants did not come back to green. Previously they have. The
pond hyacinths are yellow green. The smaller died. The ones in the berm
with the muck and no koi have darkened and are multiplying again. Our other
plants also yellowed and re-greened with iron. In our case, it was years of
growth without iron-replacement therapy.

Jim


"John Bachman" wrote in message
...
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