Viburnum's annoying ‘hair’

The Viburnum rhytidophyllum or Leatherleaf plant is native to central China and is especially decorative along the roads, even in the shade. The plant is a shrub 3 to 4 m high. The leaves are lance-shaped, 15-20 cm, pendulous, leathery with relief, dark green on top, light green and hairy. ‘Hairy’; that is, occupied with stellate (star-shaped) nonglandular trichomes. Trichomes can have many functions like defence against harmful insects, humidity regulation and even a sensory function. 

The flowers appear in May-June. They are yellowish-white in colour, unscented and grouped in clusters. The fruits are oblong drupes, dark red and then black in late summer. The plant is slightly poisonous.

Certain Viburnum species contain in their bark and leaves: coumarins (anticoagulants), and defensive substances such as iridoids, diterpenes and biflavonoids. When handling Viburnum rhytidophyllum one should be careful because the hairs (stellate trichomes) sting. The hairs can be inhaled as fine dust during horticulture and cause itching, redness of the face, even memory problems and asthenia, accompanied by loss of certain observations. The trichomes are clearly shown in two of the photos.

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