Question
will they grow in st. louis?

Answer
In St Louis you are on the edge of the growing zone for Italian cypress. The growing zone for this tree is 7-11 and St. Louis is 6. I would expect the cold weather and possible ice would do the tree in either by freezing it or the limbs breaking. I would suggest that you check with a tree nursery there and ask them for a evergreen that has similar characteristics as the Italian cypress (the narrow foliage is the one that stands out). Sorry