Malus 'Robert Nairn', a hybrid of M. baccata is a vigorous upright, rounded tree with toothed, green leaves, abundant white blooms, and small, orange-yellow fruit. Flowers in spring. Fairly disease-resistant. Prefers full sun, but tolerates partial shade. According to Fiala* an overlooked variety deserving of more attention.
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* Fiala Fr. John L. (1994) Flowering Crabapples The Genus Malus. Portland, Oregon: Timber Press.