West Sussex,
United Kingdom 
Vine weevil EEEurrh!
Today a couple of my heuchera came away in my hands, with no root left at all. This isn't a new experience but I would like to know what I can do about it please? I have turned out compost and got rid of grubs in the past. I found a few grubs this week as well. Are they seasonal or active all the year round? I've never found pupating vine weevils--are they easily seen? More importantly, how do I get rid of the little blighters?Any advice would be welcome!
13 Jan, 2020
Answers
I use vine weevil killer called Provado which you can get in garden centres. You have to use it in the summer for it to work.
14 Jan, 2020
They don't produce a pupa like a butterfly I'll post a picture for you to look at. They are active pretty much all the time except when extremely cold.
When this has happened to me I have been able to root several bits of the damaged Heuchera. Check there aren't any grubs up inside the stems and then remove all but 4 leaves of short stems. pop them into a gritty compost and keep cool.
Provado works and so do nematodes but they are temperature dependent. I find a good layer of grit is the only way to deter them.
14 Jan, 2020
Provado is no longer sold. You need to look out for Scott's Vine Weevil killing stuff.
Not had time to check, but the Neem oil stuff I used for root aphids does seem to kill the V.W. grubs.
The grubs change at maturity into white soft bodied images of the adult.
14 Jan, 2020
I top dress my pots of heucheras with grit which seems to deter them
13 Jan, 2020