Rhododendrons in the Philadelphia Area
F. J. Sholomskas, Norristown, Pa.
In February, 1964, the Rhododendron Test Garden Committee (Sylvester F. Hubbard, Oscar F. Krebs and F.J. Sholumskas, Chairman.) of the Philadelphia Chapter of the American Rhododendron Society was assigned the task of rating rhododendrons with respect to both adaptability and quality in the Philadelphia area. This assignment led to questionnaires being sent out to the members of the chapter during the winter of 1964-1965. More than 100 questionnaires returned listed 169 hybrids and 33 species. These 202 plants were then rated on quality and adaptability, and comments were encouraged.
The report table is based on both average and median ratings for varieties that received five or more reports. In a group variety or species the ratings represent the better clones obtainable unless otherwise indicated.
The committee felt that it might be helpful to readers to indicate the number of recommendations that a plant received in addition to the number of growers reporting on that plant. Under "Reports," in the table, therefore, the first numeral represents the number of people recommending the plant as possibly the best in its class, while the second numeral represents the number of people reporting the plant. It was felt that these figures might prove to be helpful to someone interested in trying a particular variety.
Quality of bloom and plant are rated from 1 to 5; 1 would be the lowest 3 average, 5 the highest. The ratings will be expressed as fractions. The numeral above the line indicates flower quality, the numeral below the line the quality of the plant. No fraction given indicates insufficient experience with this variety in our area. Adaptability rating is from excellent to worthless. An excellent rating means that the plant will take considerable exposure in that zone; a good rating means that this variety does well in that zone if not given harsh exposure. Plants with ratings of fair or poor require considerable protection from wind and sun. If considerable variation in adaptability was reported this will be indicated by fair-good, poor-fair, etc.
Nearly all reports received could be filed as zone 7a U. S. D. A. Hardiness Map (average annual minimum temperature 0° to 5° F.) or zone 6b (average annual minimum temperature of -5° to 0° F.). In Pennsylvania the Schuylkill River can almost be considered the dividing line between the two zones. Northern Delaware and southern New Jersey are both in zone 7a.
Hybrids Adaptability in Variety (Color) Reports Quality Zone 6b Zone 7a Comments A. Bedford (lav.- blue) 0-9 4/3 fair fair-good Albert Close (pink) 0-14 3/3 good good Album Elegans (white) 1-12 2/2 excellent excellent Album Novum (white) 1-8 3/2 excellent excellent Alice (pink) 0-7 worthless poor America (red) 7-30 3/2 excellent excellent Fine truss Amphion (rose) 0-6 3/2 fair good Antoon Van Welie (pink) 0-6 poor poor Arthur J. Ivens (pink) 0-9 3/4 fair-poor fair Atroflo (rose-red) 2-20 4/3 fair-good good Heavy indumentum Atrosanguineum (red) 0-13 2/3 good excellent Augfast (blue) 0-6 poor fair Azor (pink) 0-8 4/1 worthless poor Bagshot Ruby (red) 1-8 3/2 fair good-fair Beaufort (white) 0-19 2/3 good good Scented. Shy. Try sun Beauty of Littleworth (white) 0-6 4/4 poor fair-poor Belle Heller (white) 0-9 4/3 fair good-fair Betty Wormald (pink) 0-9 4/3 worthless fair-poor Blue Diamond (blue) 4-17 5/4 fair-poor fair-poor Blue Peter (lav.-blue) 16-31 4/4 good good Highly recommended Blue Tit (blue) 1-15 4/4 fair-poor fair-poor Boule de Neige (white) 14-27 3/4 excellent excellent
Fine low white
Bow Bells (pink) 0-8 5/5 worthless fair-poor Brandywine (rose) 1-6 4/2 fair good
See note 1 below
Britannia (scarlet) 0-10 4/4 poor fair-poor Cadis (pink) 6-19 4/4 fair-good good Fragrant Camich (purple-red) 0-11 1/3 good good Candidissimum (white) 0-11 3/3 excellent excellent Slow to bloom Caractacus (purp.-red) 1-16 1/3 excellent excellent Carita (yellow) 0-11 4/4 poor fair-poor Caroline (lav.-pink) 12-25 3/4 excellent excellent Scented flowers Catawbiense Album (white) 10-19 3/3 excellent excellent Favorite tall white Catawbiense Boursault (lilac) 5-18 2/4 excellent excellent Catawbiense Grandiflorum (lilac) 2-14 2/4 good excellent C. S. Sargent (red) 1-8 3/3 good excellent Slow Charles Bagley (red) 0-14 2/1 fair-good good Charles Dickens (red) 0-12 2/2 excellent excellent Slow Cheer (rose pink) 0-7 3/4 good good Blooms in fall Chesapeake (apricot) 0-7 4/2 fair good See note 1 below China (cream-yellow) 1-5 4/4 poor fair-poor Chionoides (white) 1-11 3/4 good good
Fig. 11. A plant of 'Conemaugh' blooming in the
garden of Cecil Smith, Aurora, Ore.
Cecil Smith photo
Hybrids Adaptability in Variety (Color) Reports Quality Zone 6b Zone 7a Comments Conemaugh (lavender) 3-13 3/3 good good Conewago (lav. rose) 9-22 3/2 excellent excellent Countess of Derby 0-6 4/3 worthless poor County of York (white) 7-22 4/3 good good Formerly 'Catalode' Cunningham's White (white) 0-16 2/4 fair-good fair-good Blooms in fall Cynthia (rose-red) 9-21 4/3 fair good Large model truss Daphnoides (lilac) 1-7 2/4 good good Distinctive foliage David Gable (pink) 8-15 5/4 good good One of the best Delaware (apricot) 0-5 3/2 good good See note 1 below Delicatissimum (white) 0-6 3/3 excellent excellent Slow to bloom Disca (white) 0-16 4/3 poor-fair fair-good Doncaster (red) 0-7 3/3 poor fair Dr. Dresselhuys (red) 0-23 1/2 good good Dr. Rutgers (red) 1-13 2/3 fair good E. S. Rand (red) 0-13 2/3 fair-good good Elizabeth (bright red) 0-9 4/5 poor poor English Roseum (rose) 3-20 2/4 excellent excellent See note 2 below Essex Scarlet (red) 0-7 4/1 poor-fair fair Everestianum (lavender) 3-16 3/3 good excellent Fastuosum Plenum (mauve) 0-13 3/3 poor-fair fair Double flowers F. D. Godman (red) 0-8 2/3 fair-good good Gloxineum (pink) 4-9 4/3 fair good Goldfort (cream-yellow) 1-11 4/2 fair good Goldsworth Yellow (yel.) 1-17 3/2 fair fair-good Gomer Waterer (white) 5-16 3/4 fair fair-good Fine foliage Gretchen (pink) 2-7 4/4 good good Hard to obtain Harvest Moon (yellow) 0-7 3/3 poor poor-fair Henriette Sargent (rose) 2-5 3/4 excellent excellent Hard to find Hockessin (cream) 0-7 4/2 good good See note 1 below Ignatius Sargent (rose) 5-17 3/2 excellent excellent Slightly scented Jan Dekens (pink) 0-7 4/3 worthless poor Jean Marie de Montague (red) 1-14 4/3 poor fair Jock (pink) 0-7 poor poor John Walter (red) 0-9 3/2 fair good Kate Waterer (pink) 1-6 3/3 fair good Kentucky Cardinal (red) 0-11 2/2 fair good Kettledrum (red) 0-9 2/1 excellent excellent King Tut (pink) 2-8 4/3 good excellent Kluis Sensation (red) 0-7 poor Lady Armstrong (pink 2-8 3/2 excellent excellent Slow Lady C. Mitford (pink) 0-7 poor poor Lee's Dark Purple (pur.) 1-20 2/3 good good Lenape (yellow) 1-8 4/2 good good See note 1 below Lord Roberts (red) 0-11 worthless poor Luciferum (white) 0-6 3/3 good good Slow to bloom Madame Carvalho (whi.) 0-6 2/3 fair good Madame de Bruin (red) 0-18 3/2 fair-poor fair-good Madame Masson (white) 1-12 3/2 fair good Mars (deep true red) 6-19 4/3 fair-poor fair Hard to grow well Michael Waterer (red) 0-6 2/2 fair fair Montchanin (white) 0-7 3/2 good good See note 1 below Moonstone (yellow) 0-9 5/4 poor poor Mrs. B. Robertson (yel.) 1-7 4/3 fair fair Mrs. C. S. Sargent (rose) 8-16 3/3 excellent excellent Well liked Mrs. E. C. Sterling (pink) 0-6 poor fair Mrs. Furnival (pink) 1-12 5/4 poor fair Mrs. P. D. Williams (white) 2-13 4/3 poor fair Mrs. R. S. Holford (salmon) 0-9 3/3 fair-good good
Hybrids Adaptability in Variety (Color) Reports Quality Zone 6b Zone 7a Comments Mrs. W. R. Coe (pink) 6-11 5/4 fair good Mucram (rose) 2-8 3/3 excellent excellent Myrtifolium (rose) 1-12 2/4 good good Fine foliage Naomi (pink) 0-10 4/4 poor fair Nova Zembla (red) 9-22 3/4 excellent excellent Preferred as best Old Port (plum) 0-6 1/3 good good Parson's Gloriosum (lilac pink) 2-7 2/3 excellent excellent Parson's Grandiflorum 0-6 2/3 excellent excellent (rose purple) Pink Pearl (pink) 0-13 worthless poor Pink Twins (pink) 5-18 4/4 good good Hose-in-hose flowers syn. 'Cathaem #4' Pinnacle (pink) 2-6 4/3 good good Pioneer (rose pink) 5-25 3/3 excellent excellent P. J. M. (lavender) 2-13 3/5 excellent excellent Purple winter foliage President Lincoln (lilac) 1-9 2/3 excellent excellent Princess Elizabeth 0-6 4/2 fair good (deep clear red) Professor Bettex (red) 0-5 3/2 poor fair Difficult Purple Gem (purple) 2-10 3/4 good good Needs sun Purple Splendour (purple) 0-26 4/3 fair fair Difficult. Needs shade Purpureum Elegans (purple) 0-9 2/3 good good Purpureum Grandiflorum (purp) 1-8 3/3 good good Ramapo (bright violet) 8-23 3/4 excellent >excellent Requires sun Redhead (bright red) 0-13 4/1 fair fair-good syn. 'Atrier #10' Robert Allison (pink) 4-12 5/3 fair-good good Blooms in June syn. 'Gable's Pink #2' Rosa Mundi (pink) 1-6 3/4 good good Blooms in April Roseum Elegans (rose) 13-30 2/5 excellent excellent See note 2 below Roseum Pink (rose-pink) 3-12 3/5 excellent excellent See note 2 below Roseum Superbum (rose) 1-9 2/4 good good Sapphire (blue) 0-5 poor Sappho (white, dark eye) 0-12 4/2 fair-poor fair Exotic flowers Scintillation (pink) 7-19 4/5 good good Sefton (maroon) 2-9 3/2 good good Fine June bloom Skyglow (pale apricot) 2-10 4/2 fair good formerly 'Dexter #9' Trilby (red) 0-9 3/3 poor fair-poor Unique (pale yellow) 0-14 3/5 fair-poor fair Van Weerdon Poelman (red) 0-8 2/2 fair good Vulcan (bright red) 3-13 4/4 fair fair-good Westbury (pink) 1-7 4/4 good good Wheatley (pink) 4-12 5/3 good good Lovely soft color Wilsoni (rose) 6-15 1/5 good good Fine foliage, habit syn. 'Laetivirens' Windbeam (soft pink) 8-22 4/3 excellent excellent Well liked Wissahickon (rose-red) 1-8 4/3 fair good Wyanokie (white) 5-11 3/4 excellent excellent Fine Zuider Zee (yellow) 0-5 worthless poor
Note 1: All the plants that had this comment are of the same parentage. All of these plants are rather similar especially in reference to their foliage and growth habits. While still young plants they are rather scrawny, but after about ten years they fill in nicely.
Note 2. It is said that about eight different clones are for sale as 'English Roseum', 'Roseum Elegans', and 'Roseum Pink'. It is evident that these names have been used inter-changeably by various nurseries. One form does exist that has soft rose-pink blossoms on a vigorous plant that has a superb habit and is easy to grow.
Species Adaptability in Variety (Color) Reports Quality Zone 6b Zone 7a Comments
augustinii (blue) 0-8 worthless poor brachycarpum (rose) 1-14 2/4 good good Very variable campanulatum (mauve) 0-6 2/4 fair good Very variable carolinianum (pink, mauve, white) 12-24 4/3 excellent excellent Variable. Best clones
are very fine
catawbiense (lavender) 1-10 2/3 excellent excellent Toughest of all - Catalgla' (white) 3-5 4/2 excellent excellent Very fine bloom - 'La Bar's White' 2-5 4/2 excellent excellent Pure white flowers caucasicum (yellowish) 0-11 1/4 fair-good good chapmanii (pink) 0-6 3/4 fair fair Variable degronianum (rose) 4-9 4/4 good good Variable. Blooms Apr discolor (white) 4-12 4/2 poor fair Blooms Jun-Jul, frag. fargesii (pink, early) 0-7 4/3 poor fair Difficult fastigiatum (purple) 1-9 4/4 good good fortunei (blush, pink) 7-21 4/4 good good Fragrant. Variable haematodes (red) 0-5 poor hippophaeoides (rose) 0-14 3/3 good fair impeditum (violet) 3-15 3/4 fair fair Difficult to please keiskei, usual (yellow) 1-14 3/2 fair good Very variable -dwarf form (yellow) 3-7 3/4 fair good keleticum (rose, lavender) 1-6 4/5 good good Very promising makinoi (pink) 5-17 2/4 fair good Long narrow leaves maximum (white, pink) 4-15 1/3 good good Excellent in woodland metternichii (rose) 5-13 4/4 good good micranthum (white) 0-11 2/3 excellent excellent A novelty minus (pink) 1-11 2/2 good good Very variable mucronulatum (lay.) 1-17 3/3 excellent excellent Very early bloomer -pink forms (pink) 4-8 4/3 excellent excellent oreodoxa (pink) 0-5 4/3 poor poor Shy bloomer racemosum (pink) 10-20 4/4 fair-good good Very fine russatum (pink) 0-5 5/3 fair Difficult smirnowii (lilac, pink) 0-15 2/4 good good Blooms in fall sutchuenense (lilac) 0-6 4/5 fair fair Blooms in Mar-Apr vernicosum (white, pink) 2-9 3/3 fair good - Rock #18139 (apricot) 4-6 5/3 poor-fair fair-good yakushimanum (pink) 9-17 5/5 good good Stands alone