I want to purchase a Saucer Magnolia tree for my back yard. I've done an on-line search and found that naturally, on-line nurseries sell small trees in 3 gallon pots. I am interested in getting a tree that is already at least 4-5 feet tall. Do you have a recommended source in New York City?
Here in the city I often recommend people contact the Chelsea Garden Center at their new location on 11th Avenue at 44th Street. They carry a wide range of woody trees and shrubs throughout the season and their staff I find to be very helpful and knowledgeable. As an extra bonus, if you are an HSNY member you do get a 10% discount when you present your membership card at purchase. Then there are the places down on 28th Street in the Flower District, but I must be honest and say at this moment I do not know of a reliable tree salesman down there. If you go early enough in the day you will find a number of shops open and larger material displayed on the street, but again, I'm not sure about a specific contact for magnolias.
If you are in Brooklyn or can travel to Brooklyn, then I'd suggest visiting or contacting any of these three places:
Chelsea Garden Center, their Red Hook location - 444 Van Brunt Street, Brooklyn
Liberty Sunset Gardens, also in Red Hook - 204 Van Dyke Street, Brooklyn
Gowanus Nursery, in Caroll Gardens - 45 Summit Street, Brooklyn
I think a simple Google search should provide you with phone numbers, etc. Obviously spring is here so any of the above should have their trees in stock, or they are actively receiving as we speak. Good luck and let me know what you find!