Sorbus is treated here in the broad sense, including the subgenera Aria and Torminaria. However, these two subgenera are likely to be recognized at generic rank, based on flower and fruit characters, once molecular studies can consistently resolve their placement within the Pyrinae, overcoming current difficulties with interfertility, reticulate relationships, rapid radiation, and small samples[
The taxonomy of Sorbus is complicated by apomixis, polyploidy, and hybridization among sections and genera, especially in Eurasia. Sorbus hybridizes with several other genera in the tribe Maleae, including Amelanchier (×Amelasorbus Rehder); Crataegus (×Crataegosorbus Makino); Aronia (×Sorbaronia C. K. Schneider); Cotoneaster (×Sorbocotoneaster Pojarkova); Pyrus (×Sorbopyrus C. K. Schneider), and Malus (×Tormimalus Holub [= Sorbus subg. Torminaria × Malus])[
Aucuparia subvestita (Greene) Nieuwl.
Pyrus americana decora Sarg.
Pyrus decora (Sarg.) Hyland
Pyrus dumosa (Greene) Fernald
Pyrus sambucifolia S.Watson & J.M.Coult.
Pyrus sitchensis B.L.Rob. & Fernald
Pyrus subvestita (Greene) Farw.
Sorbus americana Pursh
Sorbus dumosa House
Sorbus sambucifolia Dippel
Sorbus scopulina Hough
Sorbus subvestita Rosend. & Butters
Common Name: Showy Mountain Ash
Sorbus decora is a deciduous shrub or a tree with a bushy crown; it can grow from 3 - 15 metres tall. The plant usually produces a single main stem, but sometimes four or more are produced[
The plant is harvested from the wild for local use as a food, medicine and source of materials. It can be used as a pioneer for restoring native woodland and is also grown as an ornamental.
Although no specific information has been seen, the seed, and other parts of the plant, is 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[
Central and eastern N. America - Greenland, Saskatchewan and Nunavut to Newfoundland, south to Iowa, Illinois and Pennsylvania
Moist or dry woods, montane woods, rocky slopes, lake and stream shores, thickets; at elevations up to 1,300 metres[
]. Woods, rocky slopes and shores[
]. Found in various soils and conditions[
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Sorbus decora is a very cold-hardy tree, tolerating temperatures down to around -40°c when dormant
Succeeds in most reasonably good soils in an open sunny position[
]. Dislikes dry soils[
]. Tolerates light shade[
], though it fruits better in a sunny position[
]. This species is able to grow in poor soils and to become established on exposed broken ground[
Plants are susceptible to fireblight[
Closely related to Sorbus americana[
Fruit - raw or cooked in preserves etc[
]. The taste is best after a frost[
]. The bright red, globose to subglobose fruit can be 5 - 11mm in diameter and are borne in dense clusters[
A decoction of the inner bark, taken from the stem base, has been used as a wash and poultice in the treatment of rheumatism[
]. The decoction can also be taken internally in the treatment of a backache[
A decoction of the peeled stems has been drunk in the treatment of backaches[
This species is capable of growing in exposed conditions in poor soils[
], and so could be used in re-afforestation as a pioneer plant to provide suitable conditions for other woodland trees to be established[
The wood is close-grained, soft, moderately light with little strength, it is of no commercial value[
Seed - best sown as soon as it is ripe in a cold frame[
]. If you have sufficient seed it can be sown in an outdoor seedbed[
]. Stored seed germinates better if given 2 weeks warm then 14 - 16 weeks cold stratification[
], so sow it as early in the year as possible. Prick out the seedlings into individual pots when they are large enough to handle. Seedlings are very slow to put on top-growth for their first year or two[
], but they are busy building up a good root system. It is best to keep them in pots in a cold frame for their first winter and then plant them out into their permanent positions in late spring.