Morus indica L.

Developing fruits on Morus indica. Central London, 4th August 2021. Image Tom Christian.

Relatively small leaves on long slender petioles of Morus indica. The lamina base is truncate to cordate (Arboretum Het Leen Eeklo, Belgium – 7 September 2019). Image © Jan De Langhe - Arboretum Wespelaar.

Elegant foliage of Morus indica, with some remaining long-styled fruit-clusters (Arboretum Het Leen Eeklo, Belgium – 7 September 2019). Image © Jan De Langhe - Arboretum Wespelaar.

Glabrous branchlet and bud detail of Morus indica, the lamina upper surface is +/- rough (Arboretum Het Leen Eeklo, Belgium – 7 September 2019). Image © Jan De Langhe - Arboretum Wespelaar.

Sparsely downy lamina lower surface of Morus indica (Arboretum Het Leen Eeklo, Belgium – 7 September 2019). Image © Jan De Langhe - Arboretum Wespelaar.

Autumn display of a small bushy Morus indica, growing at the Arboretum Het Leen Eeklo, Belgium – 31 October 2019). Image © Jan De Langhe.

Low branching trunk of Morus indica (Arboretum Het Leen Eeklo, Belgium – 31 October 2019). Image © Jan De Langhe.

Fruit-cluster with long styles of Morus indica (Arboretum Het Leen Eeklo, Belgium – 10 June 2003). Image © Jan De Langhe - Arboretum Wespelaar.

A compact, deeply-lobed clone of Morus indica supplied from Hillier Nurseries in 1979 as Morus australis (Yorkshire Arboretum, UK, July 2022). In the hot summer of 2022 it fruited very freely, producing masses of small sweet syncarps. The long style is very conspicuous. Image John Grimshaw.

A sizeable Morus indica (labelled M. alba) in Nicolas Janssens garden in Belgium, 02 October 2022. Image Tom Christian.

Abundant flowering on the Hillier clone of Morus indica (Yorkshire Arboretum, UK, May 2023). Image John Grimshaw.

Morus indica in flower (Yorkshire Arboretum, June 2023). Image John Grimshaw.

Morus indica: bark on a mature tree planted on a former farmstead. Central Albania, 5 June 2023. Image Tom Christian.

'Charlotte Russe'

This is a small plant with a big identity crisis. Winner of the 2017 ‘Plant of the Year’ award at the Chelsea Flower Show, where it was exhibited under the name ‘Waisei-kirishima-shikinari’, this mulberry from Japan is a diminutive selection, growing to 1.5–2.5 m tall and broad, though it may be kept smaller by containerising or pruning. Tough, hardy and reliable, it produces copious fruit from a young age and is suitable for smaller spaces (rhs.org.uk).

It is in circulation under at least three cultivar or trade names, which are sometimes listed under species names including M. nigra and M. rotundiloba (= M. indica). Given its Japanese origin, it seems most likely to belong to M. indica, and we tentatively include it here pending further information.

'Unryu'

The spectacular Contorted Mulberry is a vigorous plant in areas with hot summers. Ultimately a tree to c. 10 m and often wider, it is perhaps among the largest contorted cultivars of woody plants: Larry Hatch recommends allowing 200 square feet to do it justice (Hatch 2021–2022). According to Bolscher & van der Wurff (1998) the leaves are large and unlobed and it is a female clone but fruit set is rare. The great dendrologist J.C. Raulston was a huge fan of Contorted Mulberry: he obtained material ‘from a California plant collector in 1981’ (Andrews, Feltwell & Lane 2012) and spent the 1980s giving away ‘hundreds if not thousands of rooted stem sections’ (Hatch 2021–2022). Likening it to Corylus avellana ‘Contorta’, Raulston advocated cutting the stems for floral displays and decoration (Andrews, Feltwell & Lane 2012).

Contorted Mulberry seems to be a relatively recent introduction to the west, but it has been suffering an identity crisis since day one. The extent to which its (western) history is known seems to hinge on whether or not you accept that ‘Unryu’ and ‘Spirata’ are the same thing: the balance of opinion seems to be stacked in favour of this view. Certainly Jacobson (1996) and Hatch (2021–2022) both treat them as identical, preferring the name M. bombycis ‘Unryu’, while Bolscher & van der Wurff (1998) and the authors of The Queen’s Mulberries (Andrews, Feltwell & Lane 2012) also treat them as identical, but prefer the name M. alba ‘Spirata’. ‘Spirata’ was introduced by H.J. van de Laar who spotted it in a Kyushu nursery in April 1979 where it was labelled M. latifolia ‘Spirata’; it was quickly imported to Europe and distributed under this name from c. 1983 (Bolscher & van der Wurff 1998).

Anybody still reading might reasonably ask why, if the plant left Japan labelled ‘Spirata’, did this name not stick, even if the parentage has subsequently been shown to differ? Hatch offers a theory that as no record of this name’s publication can be traced that predates 1959, the cultivar name in Latin form is probably invalid. Nevertheless, the origin of ‘Unryu’ (‘twisted’ in Japanese) is unclear, but it appears to have been attached to material imported into North America under M. bombycis (Jacobson 1996), perhaps by Raulston’s mysterious California collector. The limited evidence available does suggest that the name ‘Unryu’ was applied to North American stock, whereas ‘Spirata’ has been retained in Europe, and if growers on those respective continents believed they were dealing with similar selections of two different species (M. bombycis and M. latifolia respectively) the continued use of two cultivar names becomes understandable. In the taxonomy followed here both M. bombycis and M. latifolia are synonyms of M. indica. This leaves only the question of whether Contorted Mulberry belongs to M. alba or M. indica: Hatch (2021–2022) cites the distinctive style as evidence the cultivar belongs to what is here treated as M. indica, and so we treat the Contorted Mulberry accordingly, opting to use the name ‘Unryu’, fully appreciative this will not be the final word on this contorted problem.