Posted: Today at 21:11
it's a similar plant to salvia Leucamthemum.....same sort of root system and habit. So, you can cut it hard back, lift it, trim,the roots just a little and replant. however, I would not replant it outside but pot it up into a 3 or 5 litre pot and overwinter in a GH.
Best process is to take cuttimgs now ....very very easy.....AND dig up your plant. your cuttimgs will reproduce your 7' salvia bush next year.