QBARS - v21n3 Hybrids of R. yakushimanum in England

Hybrids Of Rhododendron yakushimanum In England
Frank P. Knight

The use of R. yakushimanum so far in England has been restricted to a few raisers of rhododendrons in the South. These are:

  • The Savill Gardens, The Great Park, Windsor
  • The Royal Horticultural Society's Garden, Wisley
  • Messrs. John Waterer, Sons & Crisp, Nurserymen, Bagshot
  • Mr. John Street of Woking

In the Trial of Hardy Hybrid Rhododendrons at Wisley the following have gained awards.

Award of Merit:

  • 'Telstar' (1966) R. yakushimanum x 'Pauline' (crimson, with dark eye, A.M. 1933) raised at Wisley.

Highly Commended:

  • 'Seven Stars' (1965) (A.M., London, May 2, 1967), 'Loderi Sir Joseph Hooker' x yakushimanum .
  • 'Weybridge' (1964) 'Sir Frederick Moore' ( R. discolor x 'St. Keverne' [ R. griffithianum x R. yakushimanum ]) x R. yakushimanum .

There are, in addition to these, four different hybrids in the trial which have not as yet received awards. These are:

  • another seedling from R. yakushimanum x 'Pauline'
  • R. yakushimanum x 'Borde Hill' ('Doncaster' x 'Mrs. A. M. Williams')
  • 'Pink Cheurb' ( R. yakushimanum x 'Doncaster')
  • R. yakushimanum x Fabia 'Tangerine', ( R. dichroanthum x R. griersonianum )

In London before the Rhododendron and Camellia Committee the following have gained an Award of Merit:

  • 'Streatley' ( R. aberconwayi x R. yakushimanum ), A.M. 1964, raised at the Savill Gardens.
  • 'Lady Bowes Lyon' ('Pilgrim' ( R. fortunei x 'Gill's Triumph' [ R. arboreum x R. griffithianum ]) x R. yakushimanum ) 1962, raised at Wisley.
  • 'Renoir' ('Pauline' x R. yakushimanum) 1961, raised at Wisley.
  • 'Lady Bowes Lyon' won the first prize as the best new plant at the Ghent Floralies in 1960.

The Wisley hybrids were all raised by Francis Hanger.

Mr. John Street has so far named two of his hybrids, namely, 'Marion Street' ('Alice' x R. yakushimanum ) and 'Mountain Star' ( R. yakushimanum x 'Stanley Davies').

It is my personal opinion that, with the exception of the crosses made with 'Fabia Tangerine' and 'Doncaster', the remainder show some similarity. There is, I fear, a danger of losing the most essential characteristic of R. yakushimanum and that is its compact growth. If this could be kept and stronger colors introduced ideal plants for small gardens would result. This tendency to run away is shown in 'Lady Bowes Lyon' where 'Pilgrim' the other parent, which has R. fortunei blood in it is proving too strong.

The same remarks apply to the use of the very tall growing 'Sir Frederick Moore' which is the other parent of 'Weybridge'. I would suggest backcrossing onto R. yakushimanum in order to get a restraining influence. 'Seven Stars' was described to me by Sir Eric Savill last Tuesday as growing up but never the less remarkably compact.

This is the age in the United Kingdom of small gardens and this should be borne in mind in breeding hardy rhododendrons.

Sequence of Slides:

  • Rhododendron yakushimanum , closeup of two trusses
  • 'Pink Cherub' ( R. yakushimanum x 'Doncaster')
  • R. yakushimanum x 'Fabia Tangerine'
  • R. yakushimanum x 'Fabia Tangerine'
  • 'Telstar' ( R. yakushimanum x 'Pauline')
  • Bed of yakushimanum hybrids at Windsor (Savill Gardens)