Devon,
United Kingdom 
There was a question recently about cutting back salvias and I was interested to learn that bottom growth would appear at some point.
Perhaps I got it wrong but I haven't cut back my s. microphylla Trewithen Cerise or s. Ulinginosa. They have top growth but no sign of leaves at soil level. What do I do please?
24 Mar, 2019
Answers
I always pot them up before the frosts in October and house them somewhere frost free...cut the foliage down to soil level then.You can start feeding them occasionally in early spring..fresh growth will slowly appear.Hope this helps Merlin.
24 Mar, 2019
I have S ulinginosa and I trim back 1/3 of the stems with top growth and use them as cuttings. I did this last week. the plant then sprouts from soil level.
24 Mar, 2019
I planted seeds last year and just got a lot of leaves. I'm hoping to see those blue flowers this year. Mine is still very dormant.
24 Mar, 2019
My salvia uliginosa has started new growth at soil level and I have cut back the top growth today
24 Mar, 2019
Thankyou all for advice and comments. I'll copy what you did with the Bog Sage SPG. I could try that with the micropylla too. I took cuttings last year but the microphylla haven't lasted.
I'll try giving them a bit of a feed too as Meadowland suggested. That hadn't occurred to me.
25 Mar, 2019
Give it more time. It's still early.
24 Mar, 2019