I doubt you will find a smaller one at a retail nursery.

A 2-gallon pot is not very big. At all.

Look for wildlife preserves and greenways around you having plant sales. Check your state's department of natural resources for plant sales.

Where I live there are native plant sales a few times a year put on by various organizations like the Missouri Prairie Foundation in partnership with native nurseries like Missouri Wildflowers Nursery. They have small trees available, usually in 1-2 gallon pots, but I've seen them as small as a quart. I don't generally see them that small at the retail nurseries nearby.

So maybe one of the nurseries on this list: Native Plants: A Maine Source List

I picked up a yellowwood last year in a gallon pot that didn't take much effort to plant. Now I've just got a decade or so wait to see it in bloom (if it survives)...

Does the Coast of Maine Botanical Garden have a plant sale? Remember that the designation of two gallon really isn't two gallons.

You know, I know they have sold smaller potted plants in the past from their greenhouse. I should have thought of them for trees. I'll give them a call. That sure would be a simple solution! Thanks for remembering what I should have!

I confess to using bare-root hedging stock. I mean, why would I buy a rowan or an alder for around $15 when I can buy a bundle of 10 for less than a quarter of the cost of one potted nursery tree. Literally - my beech and alders cost me around 30 cents each. That moment has passed now until autumn...my major planting season...so any containerised plants will be as tiny as I can find (and I did find a rather interesting spirea salcifolia as a replacement for the hateful buddleja in growth habit). Seems to be that hedging companies are a bit rare in the US although still much enthusiasm for rootballing in burlap...but buying trees uprooted as maiden whips means a fast and easy establishment and the possibility of training your trees from the outset (I have become increasingly fascinated with inosculation).

Ah yes, the 'gallon' conundrum. I was utterly confused for years by the casual use of '5gallon' pots over on the rose forum...which are, in fact, 5 litre pots or just under 1 actual gallon...at least as far as the Austin pot sizing goes...and nearly all other potted roses apart from miniatures.

And I have always been bewildered by the US measurement of 'cups'...which is even worse, and far more ambiguous than our imperial insistence on pounds and ounces. Teacups, beakers, builder's 1pint mugs? I went over to base 10 with vast relief...although my builder sweetheart still carries a flag of resistance for yards, feet and inches.

"Ah yes, the 'gallon' conundrum. I was utterly confused for years by the casual use of '5gallon' pots over on the rose forum...which are, in fact, 5 litre pots or just under 1 actual gallon."

Not quite :-))

A 1G nursery trade pot is .734 gallons or 2.8 liters. A 5G nursery trade pot is 3.8 gallons or 14.5 liters. These are determined by the American Standard for Nursery Stock, which was developed to standardize sizing and terminology within the industry. Why a "gallon" isn't a real gallon in volume is a bit of a US horticultural mystery whose beginning is lost in time ;-)

Well, I did say confused. Maybe put it in capitals - I am CONFUSED

And there is that annoying discrepancy between dry weight/volume and liquids!!

Mind, years of working in bars means I am very clear on just exactly how much a standard optic/short contains...although why we are still in gills and pints (not litres and cls) is another mystery.

Camp, I suppose that might change once you start driving on the correct side of the road, y’know?! It will be a waterfall of change, “What?! We can drive on THAT side? Then let’s grab those meters and liters!”

JUST KIDDING!

Coke tried to help us USers get on the metric system, and we only get as far as the 2L coke, go figure. It’s funny how my kids assume coke comes in some magical quantity called liters without ever thinking about it.

(For purposes of disclosure, “coke” is the general term for “soda/pop” if you grew up in the south. Example: “What kind of coke would you like?” “I’ll have a Dr. Pepper, thank you.” The first time I asked a non-souther that question they answered, “I’ll have...Coke...right?”)

The US gallon is smaller than the old Imperial gallon. I got a full refund on a compost bucket for the kitchen which was advertised as '1 gallon' because it was a U.S. gallon despite being on sale in the U.K. I also got to keep the container....

Well, the two-gallon redbuds are $40. I realize there is time and labor involved in raising a small tree on the side of the nursery, and then there is the profit that must be made to pay workers, bills, and leave the owner something to live on, but the frugal side of me was surprised that a 2-gallon tree was $40. I assumed for not good reason at all that they would be in the $20's.

The National Arbor Day Foundation might be a source. They sell many varieties of trees and shrubs, all smaller and I think all shipped bare-root. However, you may still need to dig large holes, because the root spread could well be larger than the size of a container. (This is an advantage overall.)

They're relatively inexpensive, even more inexpensive if you become a member. I used to be a member but dropped membership because I couldn't find a way to stop them from sending me free trees every year. At the time I lived on a city lot that already had 27 mature trees--way too many, but as a renter I couldn't remove any. However, there is now a "no free trees" option.

https://shop.arborday.org/

If you are going for small and smaller quantities , try the NH State Nursery before going to Arbor Day Foundation. I am fairly sure they ship, so if they have what you want, they are a good deal. They are sold out of something things by now.