I have large sempervivum heads that I give a yank and they come out of the soil very easily even though they were pretty established in pots before planted into ground. I noticed that the main root has been eaten out and sometimes the area close to the underside of the head is hollowed out. What could be causing this problem? I don't think I have been overwatering because I have provided much drainage when I prepared the bed for these plants that I have owned for over 5 years.

Webesemps, can you take a photo so we can see them?
Is the area rotted, soft and mushy, or just eaten out?

Thanks for timely reply!

Semp stem/root doesn't feel soft, mushy. Stem flesh has darkened appearance and part of stem is hollowed out as if it has been eaten out.
Like I mentioned before, a few heads pulled out easily. Other heads are still firmly attached (fingers crossed).

I wonder if it can be root weevils? Look in the dirt below the plant. They usually aren't a problem in semps, but it can happen.

Hey Lynn, I just found out about the above problem in my semp bed. After looking at UK Kate's problem with grubs and saw pictures of them from the links you all provided and more pics on Google, I finally know what they looked like...AND, yesterday I was flicking thru the dirt and saw a curley thing appear on my spade. IT WAS A GRUB!! ....didn't see anymore but afraid to look more deeply for fear of finding more. But at least I know what could be causing the above problem.

Did you take a photo of it Bev?

No, but the image of it uncurling in my spade and seeing the moving legs and the head sent it to its demise under a brick dropped at 3 ft...
I do remember it not being as straight in posture or as large in size as those in Kate's bucket. If I find another, I'll take a snap/click