DNA results for this apple were Early Strawberry, but MORP thinks this is an error as the actual apples in the field do not resemble descriptions of Early Strawberry. For one, these appear to ripen in the late fall or winter vs early summer. Whatever the case, we know that a row of these unknown apple trees have grown in an orchard in the Hermosa Valley for over 100 years. The photo shows the apples not yet ripe on August 12th.
Choose rootstock type depending on availability:
Malus domestica Standard sized seedling rootstock. This is what trees were historically grafted on. These will be large trees that will grow for a century or more due to their cold hardiness and drought tolerance. Plant 25 feet or more apart.
M111 Semi Dwarf rootstock. 3/4 size of standard. A good compromise if you want a slightly smaller tree. Plant 15 feet or more apart.
M7 Semi Dwarf, Smaller than M111. Probably not as long lived, but produces sooner. Longer lived than M26. Plant 12 feet or more apart.
M26 Dwarf, Short lived (a few decades), fast producing, needs staked, not drought tolerant or as cold hardy, plant as close to 1-2 feet apart.