Question on Worms

I know having worms in your garden bed is a good thing, but what about pots? Some months ago I dug up a Fragrant Plum out of the ground to put into a pot, because it had been struggling for a couple of years. After being in the pot for a few months 5 months it just kept going backwards, so I remove it, to find that there was no new root growth, but the root ball and potting mix was teeming with worms. Peoples thoughts would be appreciated.

as a rule, worms in the soil mean that the soil is conducive to the worms and also there is food for them there....... so you are on a winner there , Paul.
As for the rose, the transplant might not have been good for it, and it kept going backwards further again......