When to move a hebe. CanI still move a medium

Well from my perspective - others may disagree with me - I would advise you to wait for early spring. We've had it sweet for a while but the weather can 'turn on a dime.' Right now I'm in the midst of a horrendous winter storm. If this storm heads in your direction - good chance it will - your young evergreen will be flat-lined real quick. It won't hurt to wait a couple months so it roots in real good.

I agree with Bathgate. Hebes can be quite tender so if we get a bad spell of weather you'll be putting it at risk.

I too wouldn't consider moving at this time, even though it has been relatively mild where you live the soil won't be particularly warm.

I have moved Hebe,s from dwarf to large many times over the years through the winter, but common sense has to prevail if the ground is frozen or very cold then during a mild spell is ok, my method has always been to dig deep and you will lift a bulky fibrous root ball, this needs to go into a well prepared hole with decent compost and then heel in and mound up and top this up with a generous amount of leaf mould, it has always worked for me, that said if you are unsure then wait untill the spring and follow the above method.