Picea schrenkiana Fisch. & Mey.

It is probably fair to say that Picea schrenkiana belongs to that group of spruces that have never excited much horticultural attention, and those few cultivated examples that do exist have done nothing to dispel the reputation of Picea for being spiky and dull. This seems particularly unfair in the light of any internet search for this species which will return tantalising images of beautiful native forests in central Asia, where the species is distributed over a 1000 km west-east range in the mountains of easternmost Uzbekistan, through Kyrgyzstan and southern Kazakhstan to Xinjiang Province in north west China. In the more favourable parts of this area it can become a large tree to 60 m, forming pure forests or mixing with Abies sibirica, but in drier regions it is a much smaller tree, 20–25 m tall, growing with largely xerophytic vegetation including various Juniperus species (Debreczy & Rácz 2011).

This distribution falls to the west and north of the Tibet-Qinghai Plateau and experiences a strongly continental climate with significantly less rainfall than south of the Himalayas, where the monsoon climate prevails and where the rather similar Picea smithiana is distributed from Kashmir east into central Nepal. Consequently, like so many other conifers from central and northern Asia, P. schrenkiana was soon found to be difficult and disappointing – or at least slow and uninspiring – in cultivation across a large part of western Europe following its introduction in c. 1877–78. It was introduced via the Imperial Garden in St Petersburg, where it could be grown successfully, as indeed it would be in the more continental parts of eastern and central Europe, but in the west and particularly in the UK and Ireland early accounts of its performance were lukewarm at best (e.g. Kent 1900).

By the time of the 1931 Royal Horticultural Society Conifer Conference only a handful of respectable trees were reported from British and Irish collections, the best one then 11.9 m at Hergest Croft, the next finest 6.4 m at Dawyck (Chittenden 1932). Alan Mitchell reported another from Hergest, 10.7 m × 22 cm dbh in 1961 (Mitchell 1972) and this is probably the same latterly recorded from Park Wood at 16 m × 41 cm dbh in 1995 before its demise some time later. In 2024 the best extant trees in Britain include one 18 m × 55 cm dbh at Durris, Aberdeenshire in 2007, and a pair at Kew, one 17 m × 41 cm dbh and the other 20 m × 46 cm dbh in 2022, the latter from seed sent by Henkel in 1882 (Tree Register 2024).

There is a single record on the website monumentaltrees.com, of a tree 24.2 m × 43 cm dbh in 2019 at Schovenhorst, Putten, the Netherlands; remarkably, no others in Europe are listed (Monumental Trees 2024) though it is certainly cultivated in collections, for example at Rogów Arboretum, Poland. The BelTrees database is more helpful: it reports a handful of trees in Belgium, the best two at Meise, 6 m × 7.3 cm dbh in 2013 and 5 m × 17 cm dbh in 2018 (Arboretum Wespelaar 2024).

In North America, Slavin (1932) reported several hundred 12 year-old plants in the pineta of the Bureau of Parks, Rochester, New York, then averaging just over 1 m tall, but their origin and fate is unknown (a suggestion that some are linked to Purdom 806 is erroneous). By the early 1980s Warren (1982) could only report a single 11 m tree from the Arnold Arboretum, raised from seed received from St Petersburg in 1903. In 2024 the Arnold’s database reports four living trees, though none in good condition nor more than a few metres tall (Arnold Arboretum 2024).

From a horticultural point of view, Picea schrenkiana has never been able to overcome the double hurdle of coming from a region that severely limits its performance in cultivation across large parts of our study area, and being aesthetically comparable to (the far more beautiful) P. smithiana which is much more amenable in oceanic climate zones. Indeed, P. smithiana is the only species P. schrenkiana is likely to be confused with, but the latter has a denser habit, shorter branches, shorter, stiffer leaves and nodding (cf. pendulous) branchlets, and never forms so large nor so vigorous a tree in gardens (Bean 1976). Recent molecular investigations place both species in the same clade together with various other non-Japanese, flat-leaved Asiatic species, but the studies do not agree on the relationships within this broad group (Earle 2024).