Help! What is this please?

I was re-potting a Registered Hibiscus rosa-sinensis with which I was having issues, and found this in the soil ... what is it please? ...

 

They look like slow release fertiliser pellets.

 

They look rather shiney" for the slow release pellets - could they be eggs ? Have you tried squishing a couple ? I find the slow release usually "pop" but eggs will leave a residue on your fingers. Just a thought

 

Thank you @Nigel and @Philippa. I thought slow-release Fertiliser and T'other Half said eggs!

I wonder what the couple of white ones are?

I will have TH go squooshing ....

 

Squash one, if its fertiliser it will probably be dry inside and white powder like substance.

 

Slow release are usually a uniform colour/size and the pics don't really match.
Happy squishing anyway @Victoria

 

It looks like roots are attached to some of them?

 

Yes, there were odd little roots in the soil.

Three of them popped, no squishy ones. The soil was wet. They all (six in the ground and 24 in pots) live permanently outside.

Here is a pic I took off line of slow-release pellets ...

 

I'd say slow release pellets as well. Soil looks a little damp...is that the issue you've had with the plant?

 

Yes, it is and leaves were veining. Turns out the overpot did not have a hole in the bottom ... well, it was there just not punched out. Now punched out and plant repotted directly into it with added dry compost. Got some "ferroverde" from Spain on Monday.

Can I just use these pellets elsewhere?

Here are the potted yesterday ...

 

Ferroverde? is that green iron sulphate, as in ferro(iron) and verde(green)?
I wouldn't personally use anything for a few weeks to see if it recovers from the waterboarding it received! Anyway, you gave it fresh compost, that'll see it good for a month.
Side note
I'd love to be able to grow hibiscus rosa-sinensis outside year round

 

About this product
250 g With microelements and magnesium
Prevents yellowing of leaves