If the grub was curled up like a letter' C' and had a brown head, then it was a vine weevil grub. The love the roots of Heuchera. Water with Provado Vine Weevil Killer. Or empty the compost out, wash the roots of everything in it and replant in fresh clean compost. Use a peat free one, the weevils are not as fond of that as they are of peat based ones.
As for the green/yellow eggs, I do not know of any pest with eggs large enough to be seen other than snail and slug, but those are clear or creamy white. Could they be long term slow release fertiliser capsules? There are different coloured ones.

I agree with you on both points, Ob.

The slow release capsules would have liquid in them would"nt they. I could not see a brown head but they where like a letter c,thanks very much Owdboggy and Bulbaholic.

The capsules would have had liquid in them when they were fresh but it slowly seeps out through the walls so that they are normally dry when you find them

vine weevil are very difficult to get rid of it may be best to bin both plant and compost rather risk spreading them to the rest of your plants

vine weevil are very difficult to control may be best to bin both plant and compost rather than risk spreading them to your other plants

I don't think I would let the evil weevils make me throw good plants away. A combination of decanting, if the pot is manageable to do that, and well aimed Provado. I have got 95% of my fuschias and better geraniums through this awful winter with no greenhouse, left in their pots, picked over, soil returned and the geraniums have some fresh blooms and fuschias budding up and growing rapidly enough to take cuttings. I left one large planter as a control and it is not doing well at all. The provado will go in later when I can safely take the fleece surround away from the huddle of nine pots. I am a bit concerned that vine weevil like Heuchera as a snack!

I think that they will enjoy snacking on almost anything. For us, it is the pot grown primulas that seem to be favourite.

How i hate those evil weevils. I lose something to them almost every year ie. lillies, fuschia,s geraniums and even strawberries that i had grown in hanging baskets. Last week i discovered they had eaten the roots of my heuchera in the border. I always thought they only got into containers, obviously not.

Thanks very much everybody it all makes interesting reading,I have never had a problem like this only ever had greenfly,slugs ,and snails.So I will be keeping a close eye on things now.

Hello Mavis, I decanted my 'control pot' containing an ancient fuschia that was way behind the other pots in leaf etc. It had few delicate white roots. There were six maggots. 2 developing legs. I dead the other 3 curled up C. I repotted it, after searching the soil thoroughly, with a mixture of old and new soil.It will get a Provado drench today. I soaked the root before I replanted. A recent item in Garden the RHS mag suggested that vine weevil is active with an all year round breeding cycle. However my pots usually do very well through the summer.

Hi Dorjac thnks for the above information,the heuchera was in a container with some other plants as they are fairly well esablished ,I have decided just to leave them for now but plant nothing else and then in the autumn empty it and renew the soil. ....... Mavis