My two Hebes 'Wild Romance', seem to be suffering from frost damage both are in large pots and should be purple but are rapidly going brown. Should I hard prune and hope that new growth emerges?
Not yet. Be patient. Keep them sheltered form strong winds and give them till June so you can see where any new growth starts and then prune back to that. You could give them a drink of liquid rose, tomato or seaweed to boost them and you could also try a tonic of one soluble aspirin in a pint of water as this can boost sickly plants.
I would not prune it yet and when you do lightly,as I lost a lovely Hebe when I pruned it in the winter ,luckily I took a cutting and its now growing well.
Thanks for the information I will give them a feed and be patient