The crabapple tree, which is a close relative of the apple tree, produces small and very sour fruit. The fruit of the crabapple is not poisonous and can be consumed. Other parts of the plant, however, including the leaves, seeds and stem of the plant are toxic. These parts of the plants contain substances known as cyanogenic glycosides, which are toxic when consumed in large quantities. In general, while edible, most people do not consider the bitter-tasting crabapple fruit palatable, except when sweetened, and cooked into a jam or jelly form.
Crabapples are small, deciduous trees that reach approximately 10 to 25 feet in height and spread. They are adaptable, versatile, low-maintenance and fairly drought tolerant once established. Trees provide year-round ornamental value. In the spring, decorative blossoms appear on the tree for up to two weeks. This is followed by the presence of showy, brilliantly coloured fruit during the summer. Some varieties of crabapples also display impressive fall colours. Once leaves drop for the winter, the mottled bark and unusual branching patterns of the tree provide visual interest.
Crabapples are ornamental trees that possess colourful seasonal foliage, flowers and fruit. They are an ideal street tree candidate because of their ability to fit easily under power lines and within medians. They are also well-suited for residential planting, where they may be used as a screen, background plant or specimen tree. Some dwarf varieties will tolerate container planting. Minimise maintenance issues associated with rotting fruit by selecting a cultivar that produces small fruit, which is less likely to drop.
Crabapple fruit varies in size from 1/4 inch to 2 inches in diameter. Technically, any fruit larger than 2 inches in diameter is considered an apple. Fruit may be yellow, orange, purple or dark red in colour. Crabapples are small in size and have a proportionately small amount of edible pulp, which makes harvesting and preparation for cooking somewhat difficult and very time-consuming. The sour raw form is not valued nearly as much as the cooked and sweetened version of the fruit. Crabapple jams and jellies are highly valued, particularly from larger-fruit cultivars.
Cyanogenic glycosides are found in the leaves, seeds and stems of crabapples. These toxins can cause vomiting, difficult breathing, diarrhoea, seizures, coma and possibly death when consumed in mass quantities. Severe effects of the poison have only been observed in grazing livestock or horses. Small animals, like dogs, are more likely to experience gastrointestinal irritation following moderate consumption of toxic portions of the crabapple.