QBARS - v21n3 Notes on Yellow Flowered Rhododendrons

Notes On Yellow Flowered Hybrid Rhododendrons
Frank P. Knight, Dir. R. H. S. Wisley Gardens, England
Interest in the United Kingdom is still being maintained in the breeding of yellow flowered hybrid rhododendrons.

I have acted as the Steward for the hybrid classes of the rhododendron competitions organized by the R. H. S. for 13 years and have watched the yellow hybrids with much interest. In my mind I classify these roughly into three sets:

  1. The large leaved hybrids, from such fine yellow ssp. as R. macabeanum , sinogrande , falconeri , wightii , etc.
  2. The spate of hybrids from the intermediate growing sp. such as R. campylocarpum , wardii , litiense , lacteum .
  3. The smaller hybrids from R. lutescens , burmanicum , sulfureum , valentinianum , chryseum , ludlowii , chrysodoron , flavidum , keiskei , trichocladum , chrysanthum .

If I continued crossing I would aim at raising plants for the small garden and in this connection I have been impressed with the work being done by E. H. M. Cox and his son Peter. They have produced 'Chikor' which is the first hybrid from R. ludlowii , the other parent being R. chryseum . I like, too, 'Chink', Sir Eric Savill's hybrid between R. keiskei and R. trichocladum.

This year at Wisley R. glaucophyllum var. luteiflorum flowered freely; it is very lovely, and will, I am sure, be used as a parent for small growing yellows.

The following slides will show some of the better yellow flowered species and hybrids as they grow in the British Isles.

  • Sequence of slides
  • R. macabeanum at Trewithen
  • R. macabeanum , close up of trusses at Nymans
  • R. wightii
  • R. glaucophyllum var. luteiflorum
  • R. burmanicum
  • R. chrysanthum at Wisley
  • R. chrysanthum , close-up of single truss
  • 'Bo-Peep', R. lutescens x R. moupinense at (Wisley) Rothschild 1934
  • 'Yellow Hammer', flavidum x sulfureum , J.C. Williams
  • 'Moonshine', 'Adriaan Koster' x litiense , raised at Wisley
  • 'Moonshine Crescent', 'Adriaan Koster' x 'Hawk Jervis Bay'
  • 'Moonshine Crescent', close-up of truss
  • 'Hawk Crest', 'Lady Bessborough' x wardii , Rothschild
  • 'Hawk Crest' x 'Idealist' gave a wonderful yellow which received the A.M. at the Rhododendron Show in London on May 2nd. This has produced a large, clear yellow flowered hybrid which, at that time, was not named.
  • 'Mariloo', 'Dr. Stocker' x lacteum , Rothschild
  • 'Carolyln', wardii x 'Mrs. Lindsay Smith', Collingwood Ingram
  • 'Ivory Queen', 'Diane' x 'Phryne'
  • 'Letty Edwards', campylocarpum var. elatum x fortunei , Slocock
  • 'Lady Primrose'
  • R. hanceanum 'Nanum'
  • 'Talavera', Caerhays, R. moupinense (white form) x R. sulfureum
  • 'Chikor', chryseum x ludlowii , Cox 1962