This rounded tree produces masses of white blossoms from red buds in mid-spring. It is considered one of the best cultivars for large production of brilliantly coloured crabapples, which are bright-crimson, flushed yellow, and orange, and appear in the autumn. The fruit is excellent for making jelly, and Malus ‘Jack Humm’ is self-fertile, meaning it does not require cross-pollination to produce fruit. Malus ‘Jack Humm’ is deciduous, not native to New Zealand, and a hybrid between Malus ‘Gorgeous’ and Malus ‘John Downie’. Malus ‘Jack Humm’ was developed in New Zealand.