Picea smithiana (Wall.) Boiss.

The Morinda or West Himalayan Spruce, Picea smithiana, is one of the most distinctive of the genus – and at its finest one of the most beautiful – with the longest leaves and among the longest and heaviest cones the genus has to offer, borne on semi-pendulous branchlets giving trees a unique aesthetic. It might conceivably be confused with long-leaved forms of the Sikkim Spruce, P. spinulosa, or, on a dark night, with P. breweriana, but it can be distinguished from both by its leaves being similarly coloured on all surfaces. It is perhaps most similar to the rarely grown central Asian P. schrenkiana, but that differs in its consistently hairy, creamy brown shoots (cf. usually glabrous and yellowish-grey).

Picea smithiana is one of just three spruces distributed in the main Himalayan chain. It occurs from central Nepal westward through northern India and then into the Karakoram of northern Pakistan into northeastern Afghanistan; like its compatriot Cedrus deodara it just crosses into southwestern Tibet where river valleys dissect the main chain. It may also occur in westernmost Xinjiang near the border with Pakistan. In the eastern Himalaya south of the main range, in Sikkim, Bhutan, and Arunachal Pradesh it is replaced by P. spinulosa, while north of the main range, in southeast Tibet, it is replaced by P. linzhiensis (Farjon 2017; Debreczy & Rácz 2011; Rushforth 2008).

In native forests Picea smithiana is a large and significant tree, covering vast areas and prized for its timber. On north and west facing slopes it frequently forms forests with Abies pindrow; on different aspects it forms forests with Cedrus deodara. These associations draw trees up, and in such conditions they are often free of branches for half their height or more, with just a compact pyramid of foliage in the upper crown.

Picea smithiana came quickly to the attention of British botanists working in the region in the early 19th century. It was introduced to Scotland in 1818 when Dr Govan of Cupar, Fife, received seed from his son in India (Bean 1976). This is a curiously early date compared to other temperate trees from the same area: Abies pindrow would not arrive in Britain until 1837, and Cedrus deodara no earlier than 1822 and possibly not until 1831 (Christian 2020; 2021); Aesculus indica would not come until 1851, and Betula utilis (as B. jacquemontii) no sooner than 1831 (Bean 1976). Still there is no doubt as to the validity of the 1818 date.

Dr Govan gave these first seeds to the Earl of Hopetoun. They were raised at the family seat, Hopetoun House outside Edinburgh, by the Earl’s gardener James Smith, who germinated an unknown quantity of seeds and later grafted at least some of them onto Picea abies rootstocks. This sequence of events has led to an irrepressible, romantic ideal among Scots that the species is named after James Smith the gardener; alas, Wallich actually named the species after Sir James Smith, ‘the late immortal President of the Linnean Society’ (Wallich 1832). Leaving Wallich’s curious contradiction in terms aside, Sir James Smith had in fact been the first President of the Society and one of its founders, but he proved his mortality in 1828. The old adage that the truth should never get in the way of a good story means that James Smith the gardener (whose contributions to the cultivation of this species far outweigh those of his knighted namesake) ensure his contrbution will not be forgotten. Indeed, his horticultural achievements were significant, and before he died in post in 1850 after sixty years’ service at Hopetoun (having started as a boy aged 13) he was awarded the Royal Horticultural Society’s Silver Medal for advances in the cultivation of rhubarb (Hopetoun 2016).

Three of the trees Smith raised still survive at Hopetoun and are immortalised in the book The Heritage Trees of Scotland (Rodger, Stokes & Ogilvie 2006). At least one is clearly a graft, with a planting date of 1827. Smith seems to have routinely grafted his original plants until imported seed became readily available. As soon as it was available in quantity Picea smithiana became widely planted, in pleasure grounds, woodlands, pineta, and as lawn specimens, which can be extremely attractive at first, but after several very handsome decades P. smithiana is inclined to grow old disgracefully, forking high up and shedding lower branches (Mitchell 1996). Indeed, the late British dendrologist Alan Mitchell was rather hard on this spruce. Its unpredictable nature would irritate any forester, but at its best it is singularly handsome, with an elegant pyramidal profile clothed with soft-textured curtains of foliage hanging from the main branches on nodding to pendulous shoots, creating an aesthetic to rival (and to certain tastes exceed) that of P. breweriana, and doing so in half the time.

Hopetoun’s three survivors are neither the tallest nor largest known in UK cultivation, being 29 m tall × 89 cm dbh (the graft planted in 1827), 25 m × 97 cm, and 28 m × 99 cm, all measured in 2012 (Tree Register 2024), but they are remarkable for their survival; this is not an especially long-lived tree in cultivation, and the Tree Register’s records are peppered with notable examples ‘since lost’. The tallest on record was a tree that grew until 1970 at the Prescott Pinetum in Devon, 41 m × 97 cm when measured by Alan Mitchell in 1957. Trees of 36 m at Yester House, East Lothian (in 2006) and at Taymouth, Perthshire (in 2015), and of 36.3 m at Castle Leslie, Monaghan and 36.7 m at Caledon, Tyrone, both in 2000, and one 37 m at Cuffnells, Hampshire in 2006, could all conceivably have exceeded 41 m by now. The largest girths on record usually represent trees with a single bole, but branching from exceptionally low down, making measurement difficult and exaggerating their size even when measured at the narrowest point. The largest on an extant tree is the aforementioned example in the abandoned pinetum at Taymouth at the head of Loch Tay, 1.57 m dbh in 2015, illustrated below (Tree Register 2024).

This is the best of several examples at Taymouth, growing in moderately fertile, moist but well drained, silty, alluvial soils in an area receiving about 1 m of rainfall per year (pers. obs.). Indeed, the oceanic climate that prevails across the UK and Ireland seems to have suited the early introductions very well, likely coming from the broadly comparable climate of high-altitude northwest India. This supposition is borne out by recent introductions: seed from Uttar Pradesh, India, such as that gathered in 1994 under H&M 1823, 1824 and 1878 has grown quickly and made very handsome young trees in several UK collections, the best adding 60 cm height per year once into their stride (pers. obs.), while material from northern Pakistan and Afghanistan has generally died out, or else is represented by only a few miserable trees that have taken the better part of forty years to reach a height at which late frosts cease to damage them (pers. obs.).

This oceanic experience is naturally at odds with the continental one, where Picea smithiana is generally not hardy. Although it was offered by many eastern North American nurseries at first, few trees survived very long here, suffering either from excessive winter cold or excessive summer heat and humidity, or both. According to Jacobson (1996) all the older, larger examples in North America are to be found on the west coast, although he does not cite any. More recent introductions, representing a broader range of provenances than 19th century ones, are beginning to expand its range in American gardens. Trees raised from seed gathered in Uttar Pradesh, India, in 1984 were distributed by British Columbia Forest Services to a range of sites; for example this is the source of a tree c. 7–8 m tall (in 2021) in the VanDusen Botanical Garden, Vancouver (UBC Forums).

Material from Pakistan and Afghanistan, with a drier, colder, and more continental climate than the species experiences in India and Nepal, can establish slowly but steadily in a maritime continental climate. In the landscape arboretum adjacent to Gothenburg Botanic Garden, Sweden, a large grove of Picea smithiana was established in 1990–92 from seed gathered on the 1983 Swedish expedition to Pakistan under SEP 101 (seed collected from trees on a dry north facing slope beside the Minapin Glacier at about 3050 m asl) and SEP 534 (from the Nalar Valley, over an altitudinal range of 3000–3150 m asl) (Aldén 2006). In 2005, the tallest of 69 surviving trees was 1.5 m tall (Aldén 2006) and by 2020 the tallest seen were about 4–4.5 m (pers. obs. 2020). The SEP expedition appears to be the source of a single tree surviving at the Arnold Arboretum, where all previous attempts to cultivate the species had failed; raised from seed traceable to Pakistan received in the spring of 1984, it is now in fair condition with a dbh of 18.8 cm (Arnold Arboretum 2024). Material from SEP 101 has grown reasonably well at the Royal Botanic Garden Edinburgh, but much slower than material from Uttar Pradesh (pers. obs).

Picea smithiana is relatively common in large parks and gardens in western Europe, particularly around the Italian Lakes, and it clearly thrives in areas with warm summers so long as the air is not too dry and the soils do not dry out. It was an early immigrant to Australia and New Zealand courtesy of British nurseries, and in appropriate climate zones here old trees have survived to considerable age in large gardens and historic properties, for example a tree planted c. 1870 near Bideford, Wairarapa, at the southern end of New Zealand’s North Island, now the national champion at 27 m × 1.32 m dbh (New Zealand Notable Trees Trust 2024).

Besides the recent introductions mentioned above, which resulted in flurries of new planting in the 1990s, Picea smithiana is regrettably seldom grown now and even more seldom offered for sale. Internet searches reveal multiple vendors offering seed, but on close inspection it is usually ‘out of stock’. Individuals appear somewhat self incompatible, with isolated trees producing little if any viable seed. Garden origin seed germinates readily where multiple individuals are grown in close proximity, but the risk of hybridisation must be borne in mind.

Recent phylogenetic studies have failed to resolve the relationships of Picea smithiana. All agree that it belongs to what is essentially treated as the third major clade, containing a miscellany of Asian species ‘that are neither quadrangular-leaved [i.e. the P. asperata complex] nor Japanese’ (Earle 2024) but conclusions as to the relationships between species making up this clade vary widely between the various studies.