Privet
Description
The genus Ligustrum (family Oleaceae) includes common privet (L. vulgare) and Japanese privet (L. lucidum). Shrubs or small trees of 2-8 m (up to 12 m for L. lucidum), evergreen or semi-evergreen. Opposite, simple, glossy dark green coriaceous leaves. Small white fragrant flowers in dense terminal panicles with 4-lobed corolla and 2 stamens. Fruit is a spherical blue-black berry persisting in winter.
Habitat and distribution
One of the most planted shrubs in Madrid. Ubiquitous in residential hedges, street medians, parks and public gardens. L. lucidum is also used as a small street tree. Very evident and fragrant flowering in June throughout urban walks.
Health impact
Pollination May-July, peaking June. Moderate-high allergenicity, especially relevant due to close taxonomic relationship with olive. Olive-allergic patients frequently react to privet. Causes rhinoconjunctivitis with nasal congestion, frequent sneezing and bronchospasm in asthmatics. The intense flower fragrance may also trigger non-specific respiratory discomfort.
Cross-reactivity
High cross-reactivity with olive (Olea) and ash (Fraxinus), all Oleaceae. Ligustrum allergens share epitopes with Ole e 1 and Fra e 1. Privet may act as a primary sensitizer due to its physical proximity in urban environments.
Pollen morphology
Tricolporate pollen grain, subprolate to prolate, 22-30 μm. Long narrow colpi. Reticulate surface with medium-sized lumina. Exine 2-2.5 μm. Resembles olive pollen but slightly larger with coarser reticulum.
Did you know?
Japanese privet is considered invasive in several regions worldwide. Its black berries are toxic to humans but important food for blackbirds and starlings in winter. The name Ligustrum comes from Latin "ligare" (to bind), referencing the traditional use of its flexible branches for tying.
The information on this page is for educational purposes. For any questions about allergies, consult your doctor or allergist.