Hardy orange is almost too interesting a tree, mounting a different, striking, and often unique display each season: spring flowers, summer foliage, fall fruit and foliage—and then, in winter, the green bark of bare young twigs and horrifyingly fierce thorns. No other plant hardy to Zone 6 has a stronger claim to the most interesting month after month, decade after decade.
As above, the fruit of free-range trees is profuse. Hardy orange can also be pruned into a hedge or topiary, adding sharp geometry to the show. The trade-off is a reduced display of flowers and fruit. Hardy orange demands to be grown at least twice. Just one is not enough.