A picture would really help. Do you mean they flopped when the flowers were still in full bloom or after they faded?

I doubt it's too much water if they are outdoors. You could check the stems and see if something has taken a bite out. Another possibility is heat. Has it been hot there?

It has been warmer here than usual..up in the 70's although today we are cool again..in the 40's. I'll ask him to check for insect damage.
Joann

Sometimes hyacinths just flop. The blooms are heavier than the stem can support and they flop over. Sometimes growers will use a small stake through the bloom and down into the pot, but most of the time this goes through the bulb too which I wouldn't think is the best thing.

Unless your soil is really rich the bloom head should be smaller next year and more likely to stay upright.

The ones that flopped were all the pale blue ones. The dark blue ones stayed upright! So I guess it is just that the flower heads were too large for the stems. Hopefully next year it won't happen again.
Joann

Mine always flop

I have flopping and unflopping ones. Seems like the ones that flop are usually amid tulip leaves or other plants that make the hyacinths reach higher to make a break out of the cover, They are still beautiful, though.