Index
Practical ecological knowledge for the temperate reader.

Sorbus Sp. - Mountain Ash

Family: Roses - Rosaceae [E-flora]

"Shrub, tree. Leaf: odd-1-pinnately compound [not], petioled, deciduous; leaflets generally toothed, terminal partly fused to uppermost lateral(s) or not. Inflorescence: panicle, many-flowered; pedicel bractlets 0. Flower: hypanthium bractlets 0, stamens generally 20; ovary generally inferior, chambers 1–5, styles 1–5, generally free. Fruit: pome, generally spheric, chambers 1–5, 1–2-seeded. ± 130 species: northern temperate, tropical Asia. (Latin: ancient name) Species intergrade." [Jepson]

Local Species;

  1. Sorbus aucuparia - European mountain-ash [E-flora]
  2. Sorbus scopulina - western mountain-ash [E-flora]
  3. Sorbus sitchensis - Sitka mountain-ash [E-flora]

Key to the Species and Taxonomic Notes

1. Plants becoming trees over 5 m tall; leaflets usually more than 13, winter buds covered with long soft-hairy grey hairs; styles 2 or 3...........................S. aucuparia
1. Plants shrubby, usually less than 5 m tall; leaflets rarely as many as 13, winter buds not covered with long soft grey hairs; styles 3 to 5. 2. Winter buds rusty-hairy; calyces smooth on outside; leaflets blunt or rounded at the tip, toothed for not more than 3/4 of their length; styles 4 or 5, fruit red, glaucous...............S. sitchensis
2. Winter buds sticky, sparsely white-hairy; calyces hairy on outside; leaflets sharp-pointed at tip, toothed for most of their length; styles 3 or 4; fruit orange, not glaucous................S. scopulina
[E-flora-1]


Sorbus aucuparia - European mountain-ash

"Sorbus aucuparia is a deciduous Tree growing to 15 m (49ft) by 7 m (23ft) at a medium rate.
It is hardy to zone (UK) 2 and is not frost tender. It is in flower from May to June, and the seeds ripen from Aug to September. The flowers are hermaphrodite (have both male and female organs) and are pollinated by Insects.It is noted for attracting wildlife.
Suitable for: light (sandy), medium (loamy) and heavy (clay) soils, prefers well-drained soil and can grow in heavy clay soil. Suitable pH: acid, neutral and basic (alkaline) soils and can grow in very acid and very alkaline soils.
It can grow in semi-shade (light woodland) or no shade. It prefers moist soil. The plant can tolerate maritime exposure. It can tolerate atmospheric pollution." [PFAF]

"Sorbus aucuparia is considered an emerging invasive species in the Vancouver region by the Greater Vancouver Invasive Plant Council (2009). An emerging invasive is defined by them as: currently found in isolated, sparse populations but are rapidly expanding their range within the region. It is already well-established in the Fraser Delta." [E-flora]

"Habitat/Range Mesic to moist, open forests, fields and roadsides in the lowland zone; frequent in SW BC, rare northward along the coast; introduced from Eurasia." [IFBC-E-flora-1]

"Contraindications, Interactions, and Side Effects (Rowan Berry) — Not covered (AHP). “No health hazards or side effects are known in conjunction with the proper administration of designated therapeutic dosages of the dehydrated drug or with the consumption of fruit sauces, juices, jellies, jams, etc., produced through cooking” (PH2) (but PH2 designates no specific quantified dosage! JAD). Because of the irritant parasorbic acid (mostly or totally destroyed by cooking or drying) in untreated or unprocessed fruits, excessive intake of fresh fruits can lead to albuminuria, diarrhea, gastralgia, gastroenterosis, glycosuria, kidney damage, polymorphic exanthemas, queasiness, and vomiting (HHB; PHR). Amygdalin (342–617 ppm) and hydrocyanic acid (20–37 ppm) are reported from the frozen fruits (WOI)." [HMH Duke]

"Uses: Rowan wood, carried, increases psychic powers, and the branches are often used in fashioning dowsing rods and magical wands. Add the leaves and berries to divination incenses as well as those designed to increase psychic powers. Carrying rowan berries (or the bark) aids in recuperation, and they are added to healing and health sachets and mixtures, as well as all power, success, and luck sachets. For centuries rowan has been used for protective purposes in Europe. Two twigs tied together with red thread to make a cross is an age-old protective amulet. Cornish peasants carried these in their pockets, and Scottish Highlanders inserted them into the lining of their clothing. Walking sticks made of rowan wood are excellent tools for the person who roams woods and fields by night. Rowan carried on board ship will prevent its involvement in storms; kept in the house it guards against lightning strikes, and when planted on a grave Rowan keeps the deceased one from haunting the place.
The rowan tree planted near the house protects it and its occupants, and those rowans growing near stone circles are the most potent." [EMH Cunningham]

"As a tree with much magico-religious lore attached to it in the Gaelic-speaking parts of the British Isles (in the uplands of which it is also commonest), Sorbus aucuparia has predictably been deployed against a variety of ailments—though not nearly as widely as one might have expected. In seventeenth-century Wales the berries were eaten for scurvy,259 in the eighteenth century a purge was derived from the bark in Moray260 and in the nineteenth century some unstated part of the tree was valued in Aberdeenshire for toothache.261 A gargle made from the boiled berries262 is on record from the Highlands as well.
Ireland’s greater tradition of utilising the bark of trees for medicinal purposes finds reflection in the boiling of that for a cough cure in Louth263 and its inclusion in a herbal mixture taken for ‘the evil’ (i.e. scrofula) in Sligo.264 In Cavan the leaves have served as a poultice for sore eyes, and the berries have been eaten raw as a cleansing tonic for the blood265 ; the berries, too, have been eaten in ‘Ulster’ to rid the body of worms.266 " [MPFT]

"Medicinal Parts: The medicinal parts are the ripe, dried fruit or the dried and then boiled fruit" [PDR]
"Effects The parascorbic acid is weakly laxative and irritating to the mucous membrane. Ascorbic acid is a vitamin C supplement." [PDR]
"Unproven uses: Mountain Ash is used in folk medicine for kidney diseases, diabetes, rheumatism, disorders of the uric acid metabolism, for dissolution of uric acid deposits, menstruation disturbances, the alkalization of the blood, to improve the metabolism and for vitamin C deficiency." [PDR]
"Dosage Mode of Administration: Mountain Ash is available as whole and crude drug forms. Daily Dosage: A puree is used for diarrhea. Freshly pressed juice (or juice with sugar) is taken by the dessertspoonful for conditions of the lungs and pleura with fever." [PDR]

"Activities (Rowan Berry) — Antiinflammatory (f; PHR); Astringent (1; FEL; WOI); Catabolic (f; PHR); Depurative (f; WOI); Diuretic (f; MAD; WOI); Emetic (f; DEM); Emmenagogue (1; EFS; WOI); Irritant (1; PHR); Laxative (1; HHB; MAD; WOI); Litholytic (f; MAD); Pectoral (f; EFS; WOI); Sialagogue (1; HHB); Uricosuric (f; PHR)." [HMH Duke]

Phytochemicals
"Cyanogenic glycosides (0.06%; in the seeds 0.2 to 0.59c: traces in the fruit pulp): in the seeds amygdalin, in the fruit pulp prunasin
Fruit acids: malic acid (3 to 5%), tartaric acid
Monosaccharides/oligosaccharides: saccharose, glucose, fructose, sorbose
Parasorboside (bitter substance): parasorbic acid is formed from it through cell destruction (lactone of the (5S)-Hydroxyhex-2-en-acid-1 , pungent in odor, mucus-membrane-irritating, 0.1 to 0.3% of the fresh weight). Parasorbic acid is destroyed through dehydration or volatilized during cooking. It is present only in traces (less than 0.01%) in the cultivated variety, that contains few bitter substances.
Sugar alcohols: sorbitol
Tannins
Vitamins: ascorbic acid (vitamin C, 0.03 to 0.13%, higher content in the non-bitter fruits)" [PDR]


Sorbus scopulina - western mountain-ash

"Sorbus scopulina is a deciduous Shrub growing to 4 m (13ft) by 4 m (13ft). It is hardy to zone (UK) 5. It is in flower in May, and the seeds ripen in October. The flowers are hermaphrodite (have both male and female organs) and are pollinated by Insects.
Suitable for: light (sandy), medium (loamy) and heavy (clay) soils and prefers well-drained soil. Suitable pH: acid, neutral and basic (alkaline) soils. It can grow in semi-shade (light woodland) or no shade. It prefers moist soil. The plant can tolerates strong winds but not maritime exposure." [PFAF]

"Habitat/Range Mesic to moist glades, streambanks, forest edges and open forests in the montane and subalpine zones; frequent throughout BC, except rare W of Coast-Cascade Mountains; N to AK, E to AB and S to ND, WY, NM and N CA." [E-flora-2]

Ecological Indicator: "A shade-tolerant/intolerant to very shade-intolerant, montane to subalpine, Western North American deciduous shrub distributed in the Cordilleran region, marginally in the Pacific and Central regions. Occurs in continental boreal and wet cool temperate climates on moderately dry to fresh, nitrogen-medium soils; its occurrence increases with increasing continentality. Common but scattered in open-canopy, coniferous forests on water-shedding sites; persists in clearings. Characteristic of Mor humus forms." [IPBC-E-flora-2]

Notes: (Sorbus scopulina)
Two varieties occur in BC:
1. Leaflets often 13; stipules usually shed before end of blooming; plants from E of Coast-Cascade Mountains................ var. scopulina
1. Leaflets rarely more than 11; stipules persistent until after blooming; plants from W slope of Cascade Mountains..................... var. cascadensis (G.N Jones) C.L. Hitchc. [E-flora-2]


Sorbus sitchensis - Sitka mountain-ash

"Sorbus sitchensis is a deciduous Shrub growing to 1.8 m (6ft) at a slow rate.
It is hardy to zone (UK) 5. It is in flower in May. The flowers are hermaphrodite (have both male and female organs) and are pollinated by Insects.
Suitable for: light (sandy), medium (loamy) and heavy (clay) soils, prefers well-drained soil and can grow in nutritionally poor soil. Suitable pH: acid, neutral and basic (alkaline) soils. It can grow in semi-shade (light woodland) or no shade. It prefers moist soil. The plant can tolerates strong winds but not maritime exposure." [PFAF]

"Habitat/Range Mesic to moist open forests, forest edges, streambanks, rockslides, thickets and meadows in the montane to alpine zones; common throughout BC (except NE BC), especially southward; N to AK and YT, E to AB and S to ID, MT and N CA." [E-flora-3]

Ecological Indicator: "A shade-intolerant, montane to subalpine, Western North American deciduous shrub distributed more in the Pacific than the Cordilleran region. Occurs in maritime to submaritime subalpine boreal climates on moderately dry to fresh, nitrogen-poor soils; its occurrence increases with increasing precipitation and elevation, and decreases with continentality. Common but scattered in open-canopy, coniferous forests on water-shedding sites; persists in clearings. Characteristic of Mor humus forms." [IPBC-E-flora-3]

Notes:(Sorbus sitchensis)

Two sympatric varieties occur in BC:
1. Leaflets entire or toothed mostly above midlength................ var. grayi (Wenzig) C.L. Hitchc.
1. Leaflets toothed one-half to three-quarters their length................. var. sitchensis [E-flora-3]


Hazards

S. aucuparia, S. scopulina, S. sitchensis; Large quantities of the raw fruit can cause vomiting, especially if people are not used to the fruit. Seeds probably contain hydrogen cyanide. this is the ingredient that gives almonds their characteristic flavour. Unless the seed is very bitter it should be perfectly safe in reasonable quantities. In small quantities, hydrogen cyanide has been shown to stimulate respiration and improve digestion, it is also claimed to be of benefit in the treatment of cancer. In excess, however, it can cause respiratory failure and even death.
The seeds contain cyanogenic glycosides which, in reaction with water, produce the extremely toxic prussic acid[254]. In small quantities this acts as a stimulant to the respiratory system but in larger doses can cause respiratory failure and death[K]. It is therefore best to remove the seeds when using the fruit medicinally or as a food[254]." [PFAF]

Edible Uses

Fruits

See Bletting with regards to processing this fruit for consumption.[2]

Sorbus Sp; "Since sorbs are seldom consumed in quantity, their high tannin content is rarely hazardous. Still, discretion is the better part of valor where rowan is concerned. Rowan seeds contain amygdalin, a toxin present in the pits of many tree fruits. For this reason I prefer to make jelly or seediess jam, and I limit my intake of fresh sorbs to pre-picking tastes. My wife, who is allergie to most tree fruits, has a mild reaction to rowan berries.
Sorbs are edible straight from the tree, but most have a disagreeable raw-cranberry taste. When cooked they take on a bittersweet quality that is easy to appreciate." [Theneighforage]

Other Uses

Medicinal Uses


Cultivation

S.aucuparia; "Succeeds in most reasonably good soils in an open sunny position[11]. Grows well in heavy clay soils. Tolerates some shade[186], though it fruits better in a sunny position[K]. Prefers a cool moist position and a lighter neutral to slightly acid soil[11, 13, 200]. Dislikes shallow soils or drought[11, 200]. Succeeds on chalk or acid peats[98, 186]. A very wind firm tree tolerating very exposed and maritime positions[186, 200]. Tolerates atmospheric pollution[200]. Some named varieties have been developed for their improved fruits which are larger and sweeter than the type[183]. Plants, and especially young seedlings, are quite fast growing[186]. The fruit is very attractive to birds. 28 species of insects are associated with this tree[186]. Responds well to coppicing[186]. Plants are susceptible to fireblight[188]." [PFAF]

S. sitchensis; "This species is capable of growing in exposed conditions in poor soils[229], and so could be used in re-afforestation as a pioneer plant to provide suitable conditions for other woodland trees to be established[K]. It is rather slow-growing, however, and would only be used in situations where faster species were not so suitable[K]." "Succeeds in most reasonably good soils in an open sunny position[11]. Dislikes dry soils[188]. Tolerates light shade[188], though it fruits better in a sunny position[K]. This species is able to succeed in poor soils and to become established on exposed broken ground[229], it is thus suitable for use as a pioneer species in re-establishing woodland[K]. A slow-growing shrub in the wild, it can sometimes become a small tree up to 9 metres tall[229]. It usually produces abundant crops of fruit every year[229]. Plants are susceptible to fireblight[188]." [PFAF]

S.scopulina "Succeeds in most reasonably good soils in an open sunny position[11]. Dislikes dry soils[188]. Tolerates light shade[188], though it fruits better in a sunny position[K]. Plants are susceptible to fireblight[188]." [PFAF]

Propagation

S.aucuparia, S.sitchensis, S.scopulina; "Seed - best sown as soon as it is ripe in a cold frame[78, 80]. If you have sufficient seed it can be sown in an outdoor seedbed[78, 80]. Stored seed germinates better if given 2 weeks warm then 14 - 16 weeks cold stratification[98], 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[11], 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." [PFAF]

References


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