11. Exochorda
Lindl. (pearlbush)
One or 5
species, Asia; cultivated widely in temperate regions.
Exochorda usually is treated as comprising four or
five closely related species, but in her unpublished dissertation, Gao (1998)
presented anatomical, morphological, cytological, and genetic evidence for an
alternative classification involving a single species (E. racemosa)
consisting of three subspecies. As her subspecific combinations remain
unpublished, this treatment has not been adopted elsewhere.
Exochorda species are sometimes cultivated as
ornamentals. although they are extremely showy when in flower, their flowering
period tends to be rather short. Plants that are not pruned also tend to become
leggy, with arching stems. The most commonly cultivated taxon, E. racemosa,
escapes sporadically, but does not appear to be sufficiently aggressive in
nature to pose an invasive threat.