Posted: 02/04/2014 at 21:13
The yellow balls are likely to have been Osmacote fertiliser
These are slow-release fertiliser granules added to the potting compost.
As for the oregano - was it outside or indoors - my new oregano plant has been planted out in the garden for over a month, and I have others which have been out in the garden all winter and are fine.
My first thought with dying oregano is always that it's been overwatered - it's a Mediterranean plant that needs gritty free-draining compost or soil and hates having it's feet damp all the time.