Spiraea ×billardii Hérincq

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English Billard’s bridewort Status LU: established. 1st record: LU <1875, ITW 1949.
Lëtzebuergesch Billard-Kluddertrausch Status Eur.: established. 1st record: ?
Français Spirée de billard RA: ISEIA: B1, Watch List. Harmonia+: 0,00.
Deutsch Billards Spierstrauch Wikipedia: Wikipedia - Français - Spirée de billard | Wikispecies: Wikispecies - Spiraea × billardii
Nederlands Billardspirea Back to the list of neophytes

Report the species

Report Spiraea ×billardii to the National Museum of Natural History.

Brief description

Spierstrauch ZwieselSpiraea ×billardii Hérincq is a sterile horticultural hybrid between Spiraea alba Du Roi and Spiraea douglasii Hook. It only reproduces clonally. It grows mainly in ruderal areas and in riparian habitats. Plant habitat preferences are poorly known so far.

S. billardii is a fast-growing rhizomatous species, propagating clonally. As for other Spiraea species, it may easily form dense monospecific thickets smothering native vegetation. It is not known, however, if it has the capacity to inhibit plant successions like S. alba (Branquart et al. 2010).

Status and distribution in Luxembourg

Records of Spiraea ×billardii Hérincq in Luxembourg. Data source: Recorder-Lux, iNaturalist & GBIF, 2023-10-04.

Spiraea ×billardii Hérincq was first mentioned for Luxembourg by Koltz (1875: 66) in the section about S. salicifolia. We thus consider the first record to be anterior to 1875 (Ries & Krippel 2021).

François Léon Lefort (1917-1975) first documented the species in the wild on 1949-08-03 “along the Ernz Blanche downstream of Medernach, 300 m from the road to Diekirch”  (Herb. LUX specimen № 21985; MNHNL 2000-).

Currently, 5 records of Billard’s bridewort are accessible through the MNHNL-mdata portal (MNHNL, iNaturalist & GBIF 2019).

This horticultural species is often grown for ornamental purposes in parks and gardens. Subspontaneous or naturalised: old hedges, roadsides, embankments, wastelands (Lambinon & Verloove 2012: 326).

This Spiraea is by far the most widespread in the wild. However, the identity of the plant remains debatable: some authors distinguish Spiraea ×billardii (very pale pink corolla; narrowly conical inflorescence) and Spiraea ×Silverside Silverside (Spiraea douglasii × salicifolia) (bright pink corolla; subcylindrical inflorescence; leaf blade more regularly toothed, almost to the base), which would be much more common. However, the recognition of these two taxa seems difficult and therefore S. billardii is sometimes treated in a broad sense as a hybridogenic species that is more or less variable (Lambinon & Verloove 2012: 326).

Risk assessment

ISEIA protocol

B1 (2+2+3+2) = Watch List, reassessed on 24 January 2019 by C. Ries and M. Pfeiffenschneider. Original assessment: B0 (2+2+3+2) = Alert List (Ries et al. 2013: 19).

Harmonia+ protocol

Overall risk score 0,00 = (Overall Invasion score 0,00 x Overall Impact score 0,43) (Ries et al. 2020).

Overall risk score 0,00 = (Overall Invasion score 0,00 x Overall Impact score 0,43) (Ries et al. 2020).


Worldwide distribution

No worldwide distribution map available at CABI or GBIF (2020-03-04).


  • Branquart, E., P. Dupriez, S. Vanderhoeven, W. Van Landuyt, F. Van Rossum & F. Verloove, 2010. Harmonia database: Spiraea ×billardii Hérincq. Harmonia version 1.2, Belgian Forum on Invasive Species. URL: http://ias.biodiversity.be [accessed on 2019-10-15]
  • Lambinon J. & F. Verloove, 2012. Nouvelle flore de la Belgique, du grand-duché de Luxembourg, du Nord de la France et des régions voisines. Sixième édition. Avec la collaboration de L. Delvosalle, B. Toussaint, D. Geerinck, I. Hoste, F. Van Rossum, B. Cornier, R. Schumacker, A. Vanderpoorten et H. Vannerom. Jardin botanique national de Belgique, Meise. CXXXIX + 1195 pp. ISBN : 9789072619884.
  • MNHNL, 2000-. Recorder-Lux, database on the natural heritage of the Grand Duchy of Luxembourg. National Museum of Natural History, Luxembourg. Spiraea ×billardii Hérincq observed on 1949-08-03, occurrence ID DSS00439000013HF, via https://mdata.mnhn.lu [accessed 2021-03-12].
  • MNHNL, iNaturalist & GBIF, 2019. Spiraea ×billardii Hérincq in MNHNL-mdata, online portal combining species observation from Recorder-Lux, iNaturalist and GBIF. National Museum of Natural History, Luxembourg. URL: https://mdata.mnhn.lu [Accessed 2019-10-15]
  • Ries, C. & Y. Krippel, 2021. First records of 56 invasive alien vascular plants in Luxembourg. Bulletin de la Société des naturalistes luxembourgeois 123: 115-127. [PDF 241 KB]
  • Ries, C., Y. Krippel & M. Pfeiffenschneider, 2020. Risk assessment after the Harmonia+ protocol of invasive alien vascular plant species in Luxembourg. Bull. Soc. Nat. luxemb. 122: 197-205. [PDF 132 KB]
  • Ries, C., Y. Krippel, M. Pfeiffenschneider & S. Schneider, 2013. Environmental impact assessment and black, watch and alert list classification after the ISEIA Protocol of non-native vascular plant species in Luxembourg. Bull. Soc. Nat. luxemb. 114: 15-21. [PDF 652 KB]

 Page content last updated on 2021-03-12. Last proofread by Caroline Grounds on 2019-11-21.