Diervilla, commonly called bush honeysuckle, is a small genus of three species of deciduous shrubs belonging to the family Caprifoliaceae, order Dipsacales. All species are native to eastern North America, where they grow as low, mounding shrubs typically 1–2 metres (3–7 ft) in height and spread, forming colonies through spreading underground rhizomes.
The leaves are simple, borne in opposite pairs, and either oval or lanceolate in shape with a toothed margin. In autumn, foliage turns shades of yellow, orange, and red. Small tubular flowers, typically pale yellow, are produced in June and July. The genus is closely related to Weigela; several species once placed in Diervilla have since been transferred to that genus. Bush honeysuckles are sometimes confused with Lonicera tatarica (common wild honeysuckle) and Lonicera japonica (Japanese honeysuckle), members of the related genus Lonicera.
The three accepted species — D. lonicera, D. sessilifolia, and D. rivularis — are all endemic to eastern North America. Diervilla species serve as larval food plants for several Lepidoptera, including the common emerald (Hemithea aestivaria) and the engrailed (Ectropis crepuscularia).
Etymology
The genus name Diervilla honours Dr. Marin Diereville, a French surgeon and traveller who collected and introduced the plant to Europe around 1700.
Distribution
All three species of Diervilla are indigenous to eastern North America. They grow as low, colony-forming shrubs through a range spanning from the northeastern United States into Canada, with individual species occupying distinct sub-ranges within that broader area.
Ecology
Diervilla species serve as larval host plants for several Lepidoptera, including the common emerald (Hemithea aestivaria) and the engrailed moth (Ectropis crepuscularia). Plants spread vegetatively via underground rhizomes, often forming dense colonies in their native woodland-edge and scrub habitats.
Taxonomy Notes
Diervilla is placed in Caprifoliaceae, order Dipsacales. Several species once classified in Diervilla have been transferred to the closely related genus Weigela, which is now treated as a separate genus. GBIF recognises three accepted species in the genus.
