Hi Kate and welcome to GoY without knowing where you are in the UK it is a little hard to answer your question. I certainly isn't something we would consider doing on Moray. Dividing and replanting when the ground is frosty makes no sense what so ever. I take it this is a 'jobbing gardener'?

I have to agree with MG. I would not be dividing, and replanting herbaceous until the end of March. Yes, you can prune deciduous shrubs, roses and trees but not evergreens. Just to add, I really wouldn't want someone walking on my garden compacting the wet and soggy soil that early in the year.

I wouldn't go for it either - you can do all that sort of thing up to end of October, maybe even early November in some areas, because there's still warmth in the soil, despite cold air temperatures,but by January, the soil's really cold, which is why division and replanting early in the year is really left till March.

As for pruning, yes, some shrubs are fine being pruned in winter, especially if they're being renovated rather than just pruned, but others aren't, depends what they are and how hard he's pruning - prune back something like a rhododendron or Camellia or Forsythia or Weigela in winter and you'll have lost all the flowers that were coming.

I would suggest he's saying its okay because there isn't much gardening work in winter for all the reasons I've said,, and he needs the work/income.

Totally agree Bamboo... gardener is simply trying to set up some work to have income.

I agree with Bamboo too. Perhaps you should find another gardener?

I agree with the above. the cold soil will not encourage root growth and that is what they need to do once divided. and whilst you can do it, it is not advisable for the health of the plants.