Couple of possibilities come to mind. Did you scarify or nick the seeds? Perhaps they were harvested too early or not sufficiently dry? Weather last year - excessive heat can kill the embryo before harvesting.

Then there is different potting mix used this year? Different mixes have different water retention. The pollination issue - while it is somewhat surprising that you can grow hardys in your zone as they are notorious for not tolerating the heat, they are generally self-pollinating with some insect assistance. So I suppose it is possible that by hand-pollinating you 'might' have created some sterile seeds. But honestly, the odds of that are slim.

So I'd be much more inclined to lay it on the germinating conditions - something in them is different/off this year. Try making some adjustments in the soil temps, moisture levels, light exposure, etc. to see if it makes a difference. Dig up a few seeds to see if they have rotted. Try germinating a few in the baggie method (see FAQ) to see if they germinate.

Sorry I can't be of more help but I wouldn't give up on them yet either.

Dave

I don't think that you can "over-pollinate" the flowers. I get lots of pollinating insects, especially bumble bees, on my Hibiscus plants.

Have you tried a germination test? Roll up 4 or 5 seeds in a dampened paper towel, place the towel in a baggy and leave on the counter at room temp. Check in approx. 5 days to see if the seeds have swelled, a root is emerging, etc. Keep checking every couple days up to 2 weeks. If a root does emerge, you can go ahead and pot it up, using care not to damage the little seedling root.

Your Hibiscus plants could also be sterile. Do you know what variety you are collecting seed from?

Hibiscus seeds benefit from a 48-hour soaking prior to planting.

Let us know your progress!

Susan

Whoop they r all coming up now yea thanks everyone otherwise I would have thrown all I had planted away to guess I just didn't give em enough time