Allium hollandicum R.M. Fritsch (cult.) – A rare and probably ephemeral escape from or relic of cultivation, or a mere throw-out. Recorded in 2012 in woodland bordering an old sand pit in Bavikhove. Furthermore observed in similar circumstances in Maarkedal (Maarkebeekvalley) in 2016.
This species is often referred to as Allium aflatunense B. Fedtsch. in the horticultural trade (e.g. Ottesen 2014). The latter, however, is only very rarely offered for sale (Fritsch 2015). A. hollandicum has been considered a species of hybrid origin but Friesen et al. (1997) found no evidence that the popular cultivar ‘Purple Sensation’ contains genomes from more than one species.
Although widely cultivated, Allium hollandicum is rarely reported as an escape. Schimpf & al. (2007) present a record from Minnesota, U.S.A., and also refers to casual records from Germany.
Selected literature:
Friesen N., Fritsch R. & Bachmann K. (1997) Hybrid origin of some ornamentals of Allium subgenus Melanocrommyum verified with GISH and RAPD. Theoretical and Applied Genetics 95: 1229-1238. [available online at: http://dare.uva.nl/search?metis.record.id=137207]
Fritsch R. (1993). Taxonomic and nomenclatural remarks on Allium L. subgen. Melanocrommyum (Webb and Berth) Rouy sect. Megaloprason Wendelbo. Candollea 48: 417-430.
Fritsch R.M. (2015) Checklist of ornamental Allium species and cultivars currently offered in the trade. Publication in the Internet at: http://www.ipk-gatersleben.de/fileadmin/content-ipk/content-ipk-institut....
Fritsch R.M. (2016) A Preliminary Review of Allium subg. Melanocrommyum in Central Asia. Leibniz-Institut für Pflanzengenetik und Kulturpflanzenforschung Gatersleben (IPK): 288 pp. [available online at: https://www.researchgate.net/publication/312948014_A_Preliminary_Review_...
Ottesen C. (2014) Ornamental Alliums. The American Gardener September-October 2014: 12-17. [available online at: http://ahsgardening.org/uploads/pdfs/OrnAlliums_TAG_SO14.pdf]
Schimpf D.J., Pomroy D.L., Garske S.C. & Hansen D.L. (2007) Noteworthy collections. The Michigan Botanist 46: 80-86. [available online at: https://quod.lib.umich.edu/m/mbot/0497763.0046.302/1/--noteworthy-collec...