Garden in America this short? (4)
I believe the answer is:
yard
I believe this clue is a double definition.
'garden in america' is the first definition.
(US term for a garden)
'this short?' is the second definition.
(unit of length)
(Other definitions for yard that I've seen before include "Tract of land enclosed for a particular purpose" , "Enclosure by house" , "Imperial unit of length" , "Three feet - detectives?" , "Enclosed area by building - old measure" .)