Where Rosemary and Iris may go until bedtime? (7,4)
I believe the answer is:
'where rosemary and iris' is the definition.
The definition suggests a singular noun which matches the answer.
'go until bedtime?' is the wordplay.
I cannot really see how this works, but
'go' could be 'ting' (tinging is a kind of going) and 'ting' is found within the answer.
This may be the basis of the clue (or it may be nonsense).
'may' acts as a link.
Can you help me to learn more?
(Other definitions for potting shed that I've seen before include "outside store" , "Where plants are put in containers with compost" , "Building in which plants are set" , "Domestic nursery" , "Depths got in (anag) ? garden building" .)