Rhododendron tomentosum Harmaja - syn. Rhododendron palustre (L.) Kron & Judd; Ledum palustre L.; Ledum tomentosum Stokes - Ericaceae
marsh tea, marsh cistus, wild rosemary, Northern Labrador tea, Sumpfporst

Perennial evergreen shrub, 0.60-1.50m tall, native to North Europe, East Europe and northern Asia; leaves linear to lanceolate, 4-12 times as long as wide; flowers withe, stamens 10.

„The flowers are small, with a five-lobed white corolla, and produced several together in a corymb 3-5 cm diameter. They emit strong smell to attract bees and other pollinating insects.“

„The leaves, twigs and flower stalks are sticky from a fragrant resin that can be smelled at a distance on hot summer days. The main odoriferous ingredient of the resin is ledol, a sesquiterpene alcohol with a fine balsamic-woody odour (up to 37 % of the essential oil). It crystallizes easily (mp. 104 °C) and has therefore been called ledum camphor.“

„Marsh Tea grows well in bogs and has a very strong smell that can even cause headaches. The whole plant is reported as toxic, and effects on the central nervous system and aggressive behavior has been reported,“
[Traditional Scandinavian Beer Brewing: Microbial Inhibitory effect of Myrica gale and Rhodondendron tomentosum. Virgo, G., 2010]

„Marsh rosemary (Rhododendron tomentosumL. Stokes) H.Harmaja (formerly Ledum palustre) plants were collected at the flowering stage in marshes near Šulnys Lake (Šalčininkai District, Eastern Lithuania) in 2004. Essential oils were prepared by hydrodistillation and analyzed by GC and GC/MS. The major oil constituents were p-cymene (6.2-20.3%), iso-ascaridol (16.7-24.1%), palustrol (1.2-31.8%) and ledol (5.2-23.4%); and their percentage changed according to the sampling sites. Despite that the plant material was gathered from the limited area, significant compositional variability was observed in the essential oils. Ninety identified (two of them tentatively) compounds comprised up to 97.9% of the oils.“
[Variation in essential oil composition of Rhododendron tomentosum gathered in limited population (in Eastern Lithuania)., Judžentienė, A., Būdienė, J., Misiūnas, A., Butkienė, R., chemija, 23(2), 2012, 131-135]

„Wild Rhododendron tomentosum Harmaja shoots were collected from four localities of Estonia. Essential oils, isolated from dried samples by simultaneous distillation and extraction, were analysed using GC-FID and Gas chromatography-mass spectrometry methods. The yields of oils were in the range 0.14-0.87%. A total of 72 constituents, accounting for over 95% of the total oil yield, were identified. The major components in the all four oils studied were palustrol (15.9-53.5%), ledol (11.8-18.3%), γ-terpineol (0-31.2%), p-cymene (0.1-13.9%), lepalone (0.7-6.5%), lepalol (1.0-6.5%) and cyclocolorenone (1.0-6.4%). Two different chemotypes of R. tomentosum were found in Estonia and one of them was rich in palustrol (41.0-53.5%) and ledol (14.6-18.3%). The second chemotype, for the first time, was rich in γ-terpineol (24.7-31.2%) and contained less of palustrol (15.9-16.7%) and ledol (11.8-12.8%), but more p-cymene (12.5-13.9%). Also, γ-terpineol was identified for the first time in the oils of R. tomentosum.“
[Composition of the essential oil of the Rhododendron tomentosum Harmaja from Estonia., Raal, A., Orav, A., Gretchushnikova, T., Natural product research, (ahead-of-print), 2014, 1-8]

Thomé, O.W., Flora von Deutschland Österreich und der Schweiz, Tafeln, vol.4 t.466 (1885)

Rhododendron tomentosum, Červené blato
© Rolf Marschner (2008),

rhododendron_tomentosum_harmaja.txt · Zuletzt geändert: 2018/01/16 18:22 von andreas