Today's apple runs medium-large-by-large, a yellow-green sphere with slightly raised lenticels, some russeted to brown.
Some of these apples have a small faint rosy blush, and my tasting sample has a dramatic splash of russet spilling out from the stem well.
Northwest Greening's calyx is open and shallow, and the firm unbroken fruit has a very faint sweet aroma scented with pear.
The flesh, a very light yellow with green highlights, is medium fine-grained and a bit dry. It's crisp and dense, with a little give to the tooth. I don't think Northwest Greening is primarily an eating apple.
For all of that, it has a nice flavor, favoring the tart but not unpalatably so, mild and with hints of citrus and pear. This gives way to toast notes as the fruity juices leave towards the end of the chew. The pear returns faintly in the aftertaste.
Many sources say, without attribution, that Northwest Greening originated in Wisconsin in 1872, a Golden Russet - Alexander cross. See, for example, All About Apples' catalog. The texture and flavor of this variety do suggest some russet qualities, and NW Greening appears in the farm and agricultural reports as early as 1903 (when it was apparently controversial). Wisconsin would have been the "Northwest"--the frontier-- to the recent memory of many alive in 1872.