‘Mary Potter’ Flowering Crabapple

Few genera in the Arnold Arboretum’s collections have as rich and continuous a history as Malus, the apples and crabapples. Explorers brought seeds to Boston from far-away places; botanists gave them new scientific names; geneticists hybridized them while horticulturists evaluated and introduced them as ornamental culivars.

Malus ‘Mary Potter’ is one of those fabled cultivars. A hybrid between a Sargent crabapple (Malus sargentii ‘Rosea’) and another hybrid (M. × atrosanguinea), ‘Mary Potter’ was created in 1939 by Karl Sax , former director of the Arnold Arboretum and Harvard professor of biology. The seed parent was the Sargent crabapple ‘Rosea’, a pink-budded and white-flowered cultivar descended from a sprawling dwarf specimen collected by Arboretum founding director Charles Sargent in Japan in 1892 . The pollen parent (M. × atrosanguinea) is larger in size and rounder in form than the Sargent crabapple, and typically produces flowers flushed or fully pink in color.

Donald Wyman, onetime horticulturist in charge of the Arboretum’s living collections, was a leading expert on crabapples. He played a central role in selecting cultivars, and in 1947, selected an individual among Sax’s 1939 seedling crop as superior in its ornamental attributes. In 1955, it was officially christened with the epithet ‘Mary Potter’ (after an earlier, tentative name of ‘Arnold Snow’). With its wide habit and white drifts of flowers, ‘Arnold Snow’ may have been appropriate. However, so was the eventual name of ‘Mary Potter’, as that was also the name of one of Sargent’s daughters.

Two trees (grafts from the original seedling) dating from the original era still grow in the Arboretum. Accession 23013*A, across from Dawson Pond, was planted in 1953. However, the finer specimen is accession 181-52*B, on the northeastern slope of Peters Hill. This individual is only about 12’ tall but stretches nearly 25’ across, branching low and hugging the slope like a slow-moving avalanche when in full bloom. Prior to full bloom, the flower buds are pink, so it is wonderful to watch the transformation go from pink to white in late April to early May. The fruits—half-inch crabapples—are bright red at maturity in early autumn.

While we marvel today at this showstopping specimen of ‘Mary Potter’ growing in this perfect spot, its early years were difficult. Fresh from Sax’s nursery, it was planted in this location in 1952, right after the renovation of the Peters Hill Orchard. In 1956, while conducting an inventory of collections, Heman Howard reported that the tree was “broken by vandals” (a common occurrence at the time). Luckily, he noted that the plant had recovered the following year. Unfortunately, a second individual (181-52*A) planted nearby did not fare as well: on the November 12, Howard noted how it had been “cut off at ground by vandals.”

Luckily, the two old trees remain safe and secure, as are several new plants from 2012 that are rooted cuttings from the Peters Hill tree.