This is a poorly understood taxon, not described until 1892. Although typical hortulana may have originated in the Ozark region, supposed native plants have also been referred to this species from across the central Mississippi and lower Ohio Valleys (Hedrick 1911, Wight 1915; D, F, GC, St).. In Ky. there are colls. from BALL (KY), CAMP (GH, US), HARD (DHL, Oklahoma), MADI (GH) and elsewhere that have been named hortulana by reasonable botanists, but deeper analysis is needed to determine if this species is truly distinct and wild here. The situation is probably complicated by past cultivation and hybridization among plums; several apparent hybrids with mexicana are known from Mo. (St). P. hortulana appears close to munsoniana, with a similar range, and these two taxa have often been confused. However, it is closer to americana or mexicana in chloroplast DNA (Shaw & Small 2004, 2005), and hybrid origin from munsoniana and americana is suggested by nuclear DNA (Rohrer et al. 2008). Characters used to separate hortulana from munsoniana have been varied; see above sources for details, also Ladd & Thomas (2015). P. hortulana reportedly has fruits ripening mostly in late Jul to Sep (versus late Jun to Aug), the stones pointed at both ends (versus truncate at base); flowers larger, produced more often on slender branches (as opposed to lateral spurs), often appearing after leaves (versus before); leaves larger, becoming flatter (versus folded) and often glabrate (versus with thin persistent hais); leaf teeth more pointed and spreading, with glands at tip (versus adjacent to the sinus); plants usually not suckering much from lateral roots.