The taxonomy of the genus Malus is very confused - it has been revised on several occasions, with some authors placing species within the genus Pyrus. Recent morphologic work has suggested that Malus be retained as a separate genus based on fully adnate carpels and deeply inferior ovaries, with molecular evidence providing support. However, cultivation, hybridization, and introgression have led to hundreds of species being named within Malus and there is no clear agreement as to the number of accepted distinct species, or indeed the appropriate name for many of them. The genus requires a comprehensive worldwide revision[].

Common Name: Kaido Crab Apple

General Information

Malus x micromalus is a deciduous shrub or small tree that can grow 2.5 - 4 metres tall[].
Grown primarily as an ornamental in gardens, the fruit can be eaten. The plant is sometimes used as a rootstock for the cultivated apple.

Known Hazards

Although no specific information has been seen, the seed and other parts of the plant (but not the fruit) are likely to contain cyanogenic glycosides. When injested, these compounds break down in the digestive tract to release cyanide. Used in small quantities in both traditional and conventional medicine, this exceedingly poisonous compound has been shown to stimulate respiration, improve digestion, and promote a sense of well-being[]. It is also claimed by some to be of benefit in the treatment of cancer - though this claim has been largely refuted.
In larger concentrations, however, cyanide can cause gasping, weakness, excitement, pupil dilation, spasms, convulsions, coma and respiratory failure leading to death[].
The levels of toxin can be detected by the level of bitterness:- sweet almonds, for example, contain only very low levels of it and are safe to eat in quantity, whilst bitter almonds (which are used as a flavouring in foods such as marzipan) contain much higher levels and should only be eaten in very small quantities. Great caution should be employed if the taste is moderately to very bitter[].

Botanical References

,

Range

A hybrid of garden origin, M. baccata x M. spectabilis[].

Habitat

Not known in the wild.

Properties

Edibility Rating
Other Uses Rating
Habit	Deciduous Shrub
Height	3.00 m
Pollinators	Insects
Cultivation Status	Cultivated, Ornamental

Cultivation Details

An easily grown plant, it succeeds in most fertile soils, preferring a moisture retentive well-drained loamy soil[, ]. Grows well in heavy clay soils. Prefers a sunny position but succeeds in partial shade though it fruits less well in such a situation[, ].
An attractive ornamental, occasionally cultivated[]. It is often grown in parks and gardens in China, both as an ornamental and for its edible fruit[].
The fruit is a good wildlife food source, especially for birds[].
Cross-compatibility amongst the different species is common. Hybridization can occur naturally in botanical gardens and in the wild, or artificially through breeding[, ].
Polyploid forms and asexual seed production (apomixis) occur in some species[].
Plants in this genus are notably susceptible to honey fungus[].

Edible Uses

Fruit - raw or cooked[]. Can be dried for later use[]. The red, subglobose fruit is about 15mm in diameter[, ].

Medicinal

None known

Other Uses

The seedlings are scab and mildew resistant; they are used as rootstocks for the cultivated apples in China and Japan[, ].

We do not have a specific description for the wood of this species - the following is a general description for the wood of this genus:-
The heartwood is reddish-grey; the 12 - 30 rings of sapwood are a light reddish. When steamed, the wood becomes reddish brown to dark red-brown. The wood is hard, but has a tendency to warp. It is very difficult to splitd and is difficult to work, but is easily stained and polished. The timber converts cleanly but is moderately hard to saw. A clean finish is produced normally, but a reduction of the cutting angle to 20° is an advantage to planing. The wood is generally of too small a size for commercial exploitation but, where larger sizes are attained the wood has been used for making a wide range of items, including furniture, mallet heads, umbrella handles, cog wheels, pianos, tools etc, and also for turnery[, , ].
The wood of Malus species generally makes a good fuel[, ].

Propagation

Seed - this is a hybrid species and will not breed true. The seed is best sown as soon as it is ripe in the autumn in a cold frame. It usually germinates in late winter. Stored seed requires stratification for 3 months at 1°c and should be sown in a cold frame as soon as it is received[]. It might not germinate for 12 months or more. Prick out the seedlings into individual pots as soon as they are large enough to handle. If given a rich compost they usually grow away quickly and can be large enough to plant out in late summer, though consider giving them some protection from the cold in their first winter. Otherwise, keep them in pots in a cold frame and plant them out in late spring of the following year.
Cuttings of mature wood, late autumn in a frame[].