Picea engelmannii
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Kindly sponsored by
Sir Henry Angest
Credits
Tom Christian (2025)
Recommended citation
Christian, T. (2025), 'Picea engelmannii' from the website Trees and Shrubs Online (treesandshrubsonline.
Common Names
- Engelmann Spruce
- Épinette d'Engelmann
Synonyms
- Picea columbiana Lemmon
- Picea engelmannii f. argentea Beissn.
- Picea engelmannii var. columbiana (Lemmon) Beissn.
- Picea engelmannii var. fendleri A.Henry
- Picea engelmannii var. franciscana Lemmon
- Picea engelmannii f. fendleri (A.Henry) Rehder
- Picea engelmannii var. glabra Goodman
- Picea engelmannii f. glauca (R.Sm.) Beissn.
- Picea engelmannii glauca-pendula Beissn.
- Picea engelmannii f. microphylla Hesse ex Beissn.
- Picea engelmannii f. pendula Schelle
- Picea engelmannii var. typica Goodman
- Picea glauca subsp. engelmannii (Engelm.) T.M.C.Taylor
- Picea glauca var. engelmannii (Engelm.) B.Boivin
Infraspecifics
Other taxa in genus
- Picea abies
- Picea × albertiana
- Picea alcoquiana
- Picea asperata
- Picea asperata aggregate
- Picea brachytyla
- Picea breweriana
- Picea chihuahuana
- Picea crassifolia
- Picea farreri
- Picea × fennica
- Picea glauca
- Picea glehnii
- Picea jezoensis
- Picea koraiensis
- Picea koyamae
- Picea likiangensis
- Picea likiangensis aggregate
- Picea linzhiensis
- Picea × lutzii
- Picea mariana
- Picea × mariorika
- Picea martinezii
- Picea maximowiczii
- Picea mexicana
- Picea meyeri
- Picea morrisonicola
- Picea neoveitchii
- Picea obovata
- Picea omorika
- Picea orientalis
- Picea polita
- Picea pungens
- Picea purpurea
- Picea rubens
- Picea × saaghii
- Picea schrenkiana
- Picea sitchensis
- Picea smithiana
- Picea spinulosa
- Picea wilsonii
Trees to 40–60 m tall, 1–2 m dbh. Bark reddish-brown at first, turning grey-brown, becoming rough and fissured. Crown narrowly conical, somewhat columnar in old trees. First order branches short, slender, spreading horizontally, tips assurgent, lower branches on older trees downswept; second order branches short, dense, spreading or pendulous. Branchlets slender, stiff, pendulous on low old branches, greenish-yellow and finely pubescent at first, maturing yellowish-brown, becoming more or less glabrous, ridged and grooved; pulvini 2 mm long, nearly perpendicular to shoot. Vegetative buds ovoid-conical, to 5–6 mm long, resinous at apex; bud scales obtuse-triangular, appressed at first, later spreading, red-brown, persisting several years. Leaves spreading radially around leading shoots, crowded and directed forward above, parted beneath shoots on older wood and side shoots, (12–)15–3(–35) × (1–)1.5–2 mm, base minutely truncate, linear, straight or somewhat curved, more or less square in cross section, apex acute, not pungent; amphistomatic, with 2 narrow bands of 2–3 lines of stomata on the upper faces, and 2 bands of 4–6 lines beneath; leaf colour glaucous green. Pollen cones 1–1.5 cm long. Seed cones ovoid-cylindric, sessile, apex obtuse, (2.5–)3–7(–8) × 2–2.5(–3.5) cm, reddish-green at first, pale reddish to yellowish-brown at maturity. Seed scales obovate-obtrullate, thin, flexible, 1.2–1.5(–2) × 0.9–1.2(–1.6) cm at mid cone; upper surface smooth or finely striated, often undulate, glabrous, upper margin rounded or truncate, undulate, entire or erose-denticulate, sometimes lacerate; base cuneate. Bract scales broadly ovate, cuspidate, 3–6 mm long, entirely included, Seeds ovoid, 2–3 mm long, greyish-brown; seed wings ovate-oblong, 10–12 × 4–5 mm, yellowish-brown. (Farjon 2017; Taylor 1993).
Distribution Canada Alberta, British Columbia United States Arizona, California, Colorado, Idaho, Montana, Nevada, New Mexico, Oregon, Utah, Washington, Wyoming
Habitat An important constituent of montane to sub-alpine forests of western North America, particularly to the east of the Cascade-Sierra axis where it is abundant in the Rockies from 1000–3000 m asl. The climate is characterised by cold winters with abundant snow, short and cool summers, and high humidity. Forming pure forests or associating with Abies concolor, A. lasiocarpa, Larix lyallii, Pinus albicaulis, P. aristata, P. monticola and Tsuga heterophylla (at lower elevations) and T. mertensiana (higher elevations). In parts of its range it is sympatric with Picea pungens but typically occurs above than that species.
USDA Hardiness Zone 3-5
RHS Hardiness Rating H7
Conservation status Least concern (LC)
Taxonomic note A subspecies, Picea engelmannii subsp. mexicana, is sometimes recognised. Studies have shown it is not especially closely related to P. engelmannii and here it is treated as Picea mexicana – q.v. for further discussion.
Along with its compatriot Picea pungens, P. engelmannii was discovered by Charles Parry on Pike’s Peak, Colorado, in 1862. Seed arrived at the Arnold Arboretum the following year and it has been in cultivation ever since. The specific epithet commemorates German-American medic and botanist Georg(e) Engelmann (1809–1884), a man of extraordinarily wide botanical interests and a key figure in describing the flora of the American West.
The contemporary American dendrologist Michael Dirr laments that Picea engelmannii is ‘simply not well-adaped’ to the eastern half of North America, where it might only achieve 12–15 m height (Dirr 2009), rather paltry compared to wild trees which might achieve 40–50 m in favourable sites. In his survey of spruces cultivated at the Arnold Arboretum Warren (1982) suggests it compares favourably with P. pungens – then as now much planted in the United States – adding that the two are ‘equally handsome’ and that P. engelmannii deserves greater consideration than it receives. This consideration appears never to have materialised for it remains comparatively rare in horticulture on both sides of the Atlantic.
Picea engelmannii arrived in Britain in 1864 but, with a single exception, none of the trees known to Elwes and Henry in the first years of the 20th century could have been as old as this (Elwes & Henry 1906–1913). W.J. Bean observed ‘This handsome spruce is very hardy, and thrives better in N. Continental Europe and New England, where the winters are severe, than it does in places with a mild climate and late spring frosts’ (Bean 1976). By the time of the 1931 RHS Conifer Conference only five significant trees were reported from British and Irish collections, and by the late 1960s only two of these could be traced (Mitchell 1972) suggesting that in the oceanic climate of the UK and Ireland P. engelmannii is inclined to not only to grow slowly but also to be short lived, creating an effective barrier to popularity.
For many years the best by far in the UK was one growing on the Dawyck estate in the Scottish Borders (just outside the boundary of the famous Botanic Garden of the same name). As an unusually good example of a rare tree it had a long history of measurement, having arrived as a seedling removed from the wild by F.R.S. Balfour of Dawyck in 1902 or 1904 (accounts differ) and planted out in 1908: in 1931 it was 8.8 m tall × 14 cm dbh; 12.8 m tall in 1944; accelerating thereafter to 26.2 m × 62 cm by 1966; and 36 m × 95 cm in 2014; sadly its top had snapped out and it was standing dead by 2025 (Tree Register 2024; O. Johnson pers. comm.). A second tree of the same origin, planted nearby, was 24.3 m × 63 cm in 1966 and 26 m × 65 cm in 2014 (Tree Register 2024; Mitchell 1972). A tree at Pitcarmick, Perthshire, 25 m × 43 cm in 2017, might be of the same origin, given the friendship that existed between the owners of the two estates at the time, which is how an original ‘Balfour’ Picea breweriana came to be at Pitcarmick (M. Nairn pers. comm. 2022). Of the six trees noted from Britain at or over 25 m tall in 2024, two are at Dawyck (sensu lato), one at Pitcarmick, one at Fairburn in the Scottish Highlands – all rather cold, humid, erring towards continental microclimates – but the other two are in Cheshire, in the west of England, and in Norfolk, an increasingly warm and dry region. Working our way down the league table, fine trees in the 20–24.9 m range are found more widely, and include examples in Hampshire, Berkshire, Gloucestershire and Wiltshire in England, and Armagh and Laois in the island of Ireland (Tree Register 2024). This diversity is suggestive of this species’s adaptability, but given its extensive range in the wild the significance of provenance remains, along with the species itself, poorly appreciated.
As a wild plant Picea engelmannii is very much an interior tree, almost entirely confined to the eastern side of the Cascade-Sierra axis. Like several other spruces it shows a preference for moiser sites, hence the North American expression ‘spruce bottoms’ to describe moist, relatively low lying areas dominated by Picea species, often with unique ecological characteristics (J. Sutton pers. comm. 2025). Throughout this area it is significant both ecologically and economically, often dominating (or with Abies spp. co-dominating) vast forests, especially in the northern part of its distribution. Toward its southern limit it becomes more fragmented, with stands increasingly isolated from one another. It is an important timber tree in the north where it is known for its high yield. Historically it was favoured for telegraph poles, railway sleepers and mining timber, but now is most commonly used in the pulp wood industry (Farjon 2017).
In the north of its range Picea engelmannii meets P. glauca, to which it is most closely related, and there is a vast area of introgression where hybrids are far more common than either parent (Taylor 1993). This cross is discussed further under P. × albertiana. In a few areas P. engelmannii also occurs and hybridises with P. sitchensis, although such hybrids are far less common than those with P. glauca and they have not been formally named. In at least one locality (the inland Skeena River valley in British Columbia) P. engelmanii, P. glauca and P. sitchensis all occur together (Earle 2024).
'Argentea'
A form named for its silvery-grey foliage, apparently first recorded by Beissner (1891). Similar forms occur sporadically among seedlings (Auders & Spicer 2012).
'Blue Angel'
A vigorous plant (to 2 m tall in ten years) with good blue foliage. In American commerce since before 2000 (Auders & Spicer 2012). Unfortunately the illustration in the RHS Encyclopaedia of Conifers shows a spreading mat, bearing little resemblance to the description bar the foliage colour; perhaps this plant lost its leader and never recovered any apical dominance.
'Blue Cheops'
A broadly conical plant with blue-grey foliage. Raised from seed at Bloomer’s Nursery, New Jersey, before 1964 but probably no longer in commerce (Auders & Spicer 2012).
'Blue Magoo'
A selection with rather short, blue-grey leaves. Described by Auders & Spicer as ‘slow growing’ but capable of reaching 1.8 m in ten years. Raised in 1986 by Bucholz & Bucholz, Oregon (Auders & Spicer 2012).
'Bush's Lace'
A weeping selection with the young leaves an ‘excellent light powder-blue’. To 2 m tall × 1 m broad after ten years and eventually forming a small tree. Found in an Oregon Christmas Tree plantation by Richard Bush (Auders & Spicer 2012).
'Carlson Red Cone'
The description of this cultivar in the RHS Encyclopaedia of Conifers (Auders & Spicer 2012) is one of those that should prompt the astute reader to ask whether this selection really belongs to Picea engelmannii in the first place. Green foliage and ‘extra large’ seed cones are the two most prominent alarm bells, and the vigour is remarkable for this species, potentially to 3 m tall in ten years. The cultivar name recognises the unusual red colour of the seed cones when they are developing in spring. There is no accompanying illustration in the RHS Encyclopaedia, and online image searches are not helpful, either. Reportedly listed by Bucholz & Bucholz in 2009, we list it here principally in the hope of generating feedback.
'Compacta'
An upright pyramidal tree of modest growth, ultimately forming a small, compact tree, 1.5 m tall in ten years. The leaves are glaucous and rather narrow. Known from UK cultivation from before 1923 (Krüssmann 1985; Auders & Spicer 2012).
Dwarf Cultivars
Here we list a curated selection of cultivars that remain less than 1 m tall and broad ten years from planting. For further introductory remarks on cultivars see the notes at the end of the genus article.
'Banff'
A compact shrub raised from a witches’ broom found in the eponymous national park in Canada; it is included here as one of relatively few Picea engelmannii cultivars known to be of Canadian origin. Put into commerce by the Horsmann Nurseries, Germany, prior to 1992 (Auders & Spicer 2012).
'Blue Softie'
A slow-growing selection of very dense growth, forming a broadly-pyramidal plant to 1 m tall after ten years with pale blue leaves. Listed by the Oregon firm Bucholz & Bucholz in 2009 (Auders & Spicer 2012).
'Heike Kohout'
A witches’ broom with particularly good blue needle colour, making a compact bun of somewhat irregular growth, to 30 × 30 cm after ten years. Selected by Jörg Kohout in Germany before 2000 (Auders & Spicer 2012).
'Hobo'
A relatively vigorous plant, forming a globe 50 × 50 cm after ten years, bearing blue leaves. In cultivation in Germany and the Netherlands prior to 2000 (Auders & Spicer 2012).
'Jasper'
A globose dwarf selected from a witches’ broom found in Jasper National Park, Canada before 1992 when it was first listed by the Horstmann Nurseries, Germany. The foliage colour is bluish green in summer, turning a more vivid blue in winter (Auders & Spicer 2012).
'Ketchum'
Included here as a relatively unusual example of an extreme dwarf with grey-green leaves, rather than the bluish forms that are more frequently selected. Forming a globe 30–40 cm tall and broad after ten years. Cultivated in the Netherlands since before 2008, but its origin is unclear (Auders & Spicer 2012).
'Stanley Mountain'
An bushy, ultimately conical plant with several upright stems but lacking a distinct leader. It only just meets the definition of dwarf applied here (reaching 1 m tall in ten years) but we list it such as it is most likely to be used in situations where so-called dwarf forms would be the obvious choice. The young spring growth is a very fine silvery-blue, becoming duller later in the growing season. Derived from a witches’ broom found by Jerry Morris before 1999 (Auders & Spicer 2012).
'Fendleri'
A name applied to a tree cultivated at the Royal Botanic Gardens, Kew, compared by Augustine Henry to a collection made in New Mexico c. 1847 by Augustus Fendler (1813–1883) and possibly raised from seed collected by Benedict Roezl (1824–1885) (Elwes & Henry 1906–1913). The Kew tree has been described as ‘vigorous…with pendulous branches and thin needles’ (Auders & Spicer 2012) but it may no longer be standing.
'Glauca'
In a species known to produce vividly blue trees in wild populations, the cultivar name ‘Glauca’ could charitably have been described as unhelpful when it was first used by nurseryman R. Smith in 1874 (Auders & Spicer 2012). This has not changed, and we include it here for completeness and historic context only. Beissner (1891) deployed the name more sensibly, as Picea engelmannii f. glauca (R.Sm.) Beissn., and in this spirit a horticultural group (Glauca Group) could arguably be erected. The problem would be deciding where ‘bluish’ became sufficiently blue for a Group name to apply, and then applying that ruling consistently (and expecting others to do the same!) Nurseries have sensibly avoided that problem by giving unique cultivar names to their good blue selections, the best of which would probably leave Smith’s ‘Glauca’ looking decidedly grey.
'Glauca Pendula'
A more useful cultivar name than ‘Glauca’ (see above) in that the name applies to a distinctive clone which was raised from seed gathered in Utah by C.A. Purpus in 1899. It is still in cultivation. ‘Glauca Pendula’ forms an upright leader bearing pendulous branches and branchlets; the foliage is a good powder-blue. Growth is slow to moderate, to 1.5 m in ten years, and due to their habit plants remain rather slender for a long time (Auders & Spicer 2012).
'Hoodie'
A plant of slow, somewhat irregular, dense growth with rather short leaves. It was listed by the Iseli Nursery of Oregon in 1991 (Auders & Spicer 2012).
'Microphylla'
A shrubby plant of compact growth, bearing very short leaves. Raised in the Hesse Nurseries, Germany, before 1891 (Beissner 1891). It is probably no longer in cultivation.
'Snake'
Synonyms / alternative names
Picea engelmannii 'Glauca Virgata'
Picea engelmannii 'Virgata'
An alarming-looking plant with irregular, whip-cord like first order branches that are very sparsely branched, and a growth habit comparable to Picea abies ‘Virgata’. Auders & Spicer caution that ‘no two trees look alike’ (and they probably chose one of the more photogenic examples for their illustration on pages 630–631). Found as a seedling by Dr I. Martin, Germany, before 1985 (Auders & Spicer 2012).
'Vanderwolf's Blue Pyramid'
A popular selection, combining excellent blue foliage colour with a compact, fastigiate habit, to 2 m tall in ten years. Found before 1971 by Pete Vanderwolf and put into commerce by John Vermeulen & Son Inc. of New Jersey (Auders & Spicer 2012).