I can recommend two companies. I have bought 50+ trees and plants from them and have been very satisfied with the quality of the merchandise. They are Fedco Trees in Maine, and St. Lawrence Nurseries in Potsdam, NY.

Here is a link that might be useful: St. Lawrence Nurseries

Here's the link for Fedco Trees:

Here is a link that might be useful: Fedco Trees

My first choice among fruit tree companies is Burnt Ridge nursery. Their prices are quite good too.

~Chills

Here is a link that might be useful: Burnt Ridge Nursery

bay laurel, millers, raintree, and stark bros, are 4 other very good nurseries

For zone 4 adapted plants I would say Fedco and Cummins are the two best ones. St. Lawrence also specializes in cold-hardy fruits but I have never dealt with them myself.

Scott

I am looking for a mail order company for a sub-tropical fruit tree called babaco. It is reported to grow well in a container. The fruit is delicious. Any advice?

Raintree is great for fruit trees:

http://www.raintreenursery.com/catalog/index.cfm

For a company which carries subtropicals, you could search my favorite site Cindy's Catalogue of Garden Catalogues, which lists websites of all companies selling plants:

http://www.gardenlist.com/

Carla in Sac

Before you order from any nursery, make sure you check them out at Garden Watchdog. Its a feedback forum on nurseries. You'll be surprised on some of the well known mail order nurseries that have a terrible feedback record. Garden Watchdog is a must! I hope this helps, John

Garden Watchdog is good, but some of the really bad ones - like the nursery at TyTy aren't listed because they threatened lawsuit over the numerous negative(but true!) reviews they'd received.
All the nurseries that have been listed thus far are good, but certainly, for a zone 4 or colder site, Fedco, St. Lawrence and Cummins will have the appropriate selections - on the appropriate winter-hardy rootstocks.
Another one to check out is Edible Forest Nursery - he does zone 3/4 plants.

I wondered why I couldn't find TyTy there. I thought the reviews might be some amusing reading. TyTy's site is so absurd that it can be entertaining.

"TyTy's site is so absurd that it can be entertaining."

It's like it should be an "herb" nursery, if you catch my drift.

Before Garden Watchdog dropped them altogether, undoubtedly over threat of lawsuit as was said above, that watchdog site sent you to a statement if you clicked on TyTy's name. The statement said that certain sites were not listed but that you should contact the state's consumer affairs agency to inquire before ordering. I don't live extremely far away and someday when in the vicinity am going to drop by to see it with my own eyes.

I'd never heard of Tyty and so I googled it and checked out the website. Good heavens, every webpage selling their plants has women showing half their breasts, I'd thought I'd mistakenly hit a porn site! Does that really sell persimmon trees??? Just bizarre!
Carla in Sac