Sour little crabapples quietly keep the world's apple orchards working
Walk through a commercial apple orchard and every sixth or seventh tree may be a crabapple. Nobody grows them for fruit, which is mostly too sour to eat. They are there as pollen donors, because many apples cannot fertilise themselves, and their hardy roots can help sweet varieties survive harsh northern winters.
Apples and crabapples belong to Malus, a genus of somewhere between about 32 and 57 species of small trees in the rose family, native to the temperate Northern Hemisphere. Its fossil leaves go back to the Eocene, found both in Idaho and on Russia's Kamchatka peninsula. Mature trees stand four to twelve metres tall with dense, twiggy crowns, and many species hybridise freely, which is part of why the family tree is so tangled.
Spring blossom arrives once enough warmth has accumulated, and each flower has five petals in white, pink or red. Many types are self-sterile and need bees to carry pollen from a different tree; Granny Smith and Golden Delicious are among the minority that can pollinate themselves. Growers choose crabapples that bloom at the same moment as their main crop, plant them among the rows or graft crab branches onto apple trees, and in a pinch set buckets of cut crabapple blossom beside the hives. The fruit that follows is a pome; slice one crosswise and the five seed chambers form a star, their seeds containing cyanide.
Crabapples have their own uses. Their high malic acid content makes them puckeringly tart, yet some Southeast Asian cooks prize them as a sour relish with salt and chilli or shrimp paste, and a few cultivars are sweet. Rich in pectin, their juice sets into a ruby jelly spiced with ginger, nutmeg and cinnamon, and a handful can sharpen cider. Their abundant flowers and tiny fruit also make them favourites for bonsai and small gardens, where the fruit often hangs on through winter.
Even the timber is useful. Applewood smoulders slowly and cleanly, giving smoked food a mild sweetness. It is so hard to carve once dry that in the early 1900s some two million board feet a year went into hand saw handles.
Source: Malus
