water hyacinth problem

by Shawn
(Canada)

This is our second year with a pond, it measures 8'x11'x2' and contains about 12 large goldfish. We live in Ontario, Canada and the pond is in full sun, all day.

Our water hyacinths turn yellow and brown and don't spread very much.

There is a waterfall and skimmer which causes slow movement in the pond so we keep the plants in floating rings. Could this be the problem?

Doug says

Yellow leaves on water hyacinths usually mean "stress".

So - you have full sun - that's fine.
You have fish eating the roots. Hmmm
You contain them in rings - not usually a problem
You have cool water ???
You still have moving water even though the plants are in rings - a bit of a stressor

So - I'm guessing here because you don't say how bad the problem is. There's always "some" yellowing of old leaves and "bulbs" as the plants mature. This is natural and expected. A plant won't just stay "green" all summer as it grows and matures. Those old leaves are going to waste away.

If the problem is really bad, then I'd have my water checked for balance (mind you, with fish in there, it should be fine)

So I'm guessing but I'd say you don't have a lot of root growth and subsequent top growth because of the fish and what you're seeing is die-back of a normal kind perhaps accelerated by the lack of roots.

The other issues are other plants in the pond? Are they doing OK?

And what kind of runoff goes into your pond? For example, if you're using a weed and feed or other lawn chemicals, then you're not going to be very happy with spray drift or runoff into your pond area (are your neighbours using this stuff?)