6-foot tree in 5-gallon pot.  
Zone 3. This is our favorite eating apple.  A lighter coloured fruit surprises when you bite into it.  Sweet, crisp, somewhat similar to a Gala but, well… better!   Terrific for canning, baking, etc.
 
Trees will reach a mature height of 15-20 feet and a spread of 12 ft.  Apple trees should be pruned for improved production and easier picking!
 
*Apple trees in rural areas need a cross-pollinator to produce fruit (urban centres have enough pollen in the air from existing apple trees). Be sure you have 2 different types of apple trees to achieve cross-pollination.