Effect of growth substances on the rooting of cuttings of rhododendron species
Institute of Dendrology
Polish Academy of Sciences
Parkowa 5, 62-035 Kórnik, Poland
Cuttings of the following rhododendron species
were rooted: the evergreen R. catawbiense Michx. ‘Grandiflorum’, R. ‘Cunningham's White’,
R. brachycarpum D. Don ex G. Don, R. pachytrichum Franch.
(with green and red shoots), R. yakushimanum Nakai as well as the deciduous R.
atlanticum (Ashe) Rhed., R. calendulaceum (Michx.) Torr., and R. viscosum (L.)
Torr. The cuttings were treated with IBA (0.5, 1, 2, and 4%) in talcum powder
with or without the fungicide Captan (2:1), or else with Seradix B2
(containing 0.4% IBA) and B3 (containing 0.8% IBA). The rooting level depended
strongly on species. The highest percentage of rooted cuttings was recorded for
R. catawbiense ‘Grandiflorum’, R. ‘Cunningham's White’,
R. atlanticum, and R. viscosum, irrespective of the applied growth substance.
R. brachycarpum cuttings rooted the best when 2% IBA had been applied with or without Captan.
Rooting of R. pachytrichum strongly depended on the form: with red or green
shoots. Cuttings of red shoots rooted much better than those of green shoots,
irrespective of the applied growth substance. Cuttings of R. yakushimanum
rooted the best after application of 4% or 2% IBA with or without Captan, while
R. calendulaceum after 1% IBA with 1% Captan. Application of Captan alone and
Seradix B3 did not give positive effects.
Nawrocka-Grze¶kowiak U., 2004. Effect of growth substances on the rooting of cuttings of rhododendron
species. Folia Horticulturae 16/1: 115-123.