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GARDENERS' CHRONICLE 



Chinese Rhododendrons 



TWENTY-FIVE years ago the Himalayas were 

 considered to be the headquarters of the genus 

 Rhododendron. In these few short years so many 

 new species have been introduced that we have abundant 

 evidence in our gardens today that China is the native 

 habitat of the greatest number of species. French mis- 

 sionaries, Pere Delavay, Abbe David and Pere Farges, 

 sent home seeds of several of the earlier introduced 

 species to France. We are, however, indebted to Mr. 

 Ernest H. Wilson. Mr. George Forrest and those who 

 have so generously financed their expeditions, for by far 

 the larger number of new species recently introduced 

 from China. Today upwards of 300 named species are 

 in cultivation, and many more seedlings are growing 

 under numbers. 



Thanks to the 

 hybridist, Rhodo- 

 dendrons are our 

 most valuable 

 evergreen flower- 

 ing shrubs, and 

 the Azaleas sup- 

 ply the richest 

 coloring in the 

 pleasure grounds 

 during May and 

 early June. The 

 newer Chinese 

 species appear to 

 possess almost 

 boundless possi- 

 bilities in the 

 hands of the hy- 

 bridist. In shel- 

 tered positions the 

 first flowers of R. 

 sutchucncnse open 

 during early 

 Spring. Onwards 

 until July and 

 August a succes- 

 sion of flowers 

 open with unflag- 

 ging interest, ter- 

 minating with R. 

 aurkulatiim. This 

 species and R. dis- 

 c ol or, which 

 flower about mid- 

 Summer, should in the hands of the breeder give us a 

 valuable race of summer-flowering evergreen species. 



Rhododendrons as a whole are well known to prefer a 

 somewhat moist position and shelter from the midday 

 sun. It is doubly necessary when planting the species 

 named to give shelter, or the blossoms are ver}^ short- 

 lived, opening as they do in the height of Summer. 



As an indication of how widely the newer introduc- 

 tions vary in habit, collectors tell us that in China R. 

 calophytum is an evergreen shrub or tree up to 30 feet 

 high, while leaves on some of the plants in cultivation 

 exceed 1 ft. in length. At the other extreme we have 

 R. prostraHim a few inches high, and R. intricatum with 

 leaves a quarter of an inch to half an inch in length. 

 Similar comparisons may be made in the flowers. R. dis- 

 color and R. auriculatmn have blossoms 4 inches to 6 

 inches in diameter, while the flowers of R. micranthnm 

 are a third of an inch to half an inch across. 



A basket bouquet of the neiv water lily, Mrs. Edzfard IVhitaker, with petals of a 

 delicate blue, shading into a deeper blue, and stamens a golden yellow, e.vhibited by 

 George H. Pring, Horieulturist of the Missouri Botanical Garden, and awarded the 

 National Association of Gardeners' gold medal at the convention in St. Louis. 



With such a varied and interesting genus of plants no 

 wonder can be expressed at the enthusiasm of amateur 

 and professional horticulturists in the Rhododendron 

 family. The war obviously has hindered developments 

 during the last five years, but interest now must expand 

 in all directions with so much valuable material at hand. 

 Peat has been considered indispensable for the culti- 

 vation of Rhododendrons, but while a certain amount may 

 be used with advantage, the fact that it contains no lime 

 is the reason why Rhododendrons revel in districts where 

 peat is abundant. Mr. Forrest is of the opinion that some 

 at least of the new species should thrive in soil contain- 

 ing lime, and it will be interesting to watch experiments 

 in this direction. In the light sandy loam at Kew Rhodo- 

 dendrons are a leading feature. When preparing beds 



or stations for Rho- 

 dodendron leaf- 

 mold is freely 

 nii.xed with the 

 Kew soil. Truck- 

 loads of peat have 

 been used in days 

 gone by, but the 

 amount used has 

 gradually dimin- 

 ished, and frequen- 

 ters of Kew will 

 a d m i t that the 

 [ilarits have not 

 Nufifered in conse- 

 ([uence. 



^'\'hile some shel- 

 ter from the heat 

 uf the midday sun 

 is an advantage in 

 the cultivation of 

 our present race of 

 evergreen hybrid 

 Rhododendrons. 

 w ith at least a con- 

 siderable number 

 of the new Chinese 

 -pecies shelter is 

 most important. 

 K. sittchiieiiense, R. 

 Williamsianiim and 

 R. 'oreodoxa, for 

 example, because 

 they flower early 

 in the year, and R. discolor and R. auriculatuin. require 

 shelter for the flowers in June, July and August. Other 

 species indicate by their behavior in our gardens that 

 they are shade-loving species. R. Sotdiei, R. orcotrephes 

 and R. orbiculare {rotundifoliuni) being notable ex- 

 amples. How best to provide the desired shelter will 

 largely depend on local conditions. Shrubbery borders, 

 usually with a western aspect, may provide exactly the 

 conditions suitable for Rhododendrons. 



Seeds provide a ready method, and with few excep- 

 tions the best means of increasing the Chinese species. 

 R. impeditum ( fastigiate group) flowers in eighteen 

 months from seeds, R. racemosmn in two years, and R. 

 Souliei and R. orcotrephes in three or four years. Cut- 

 tings of numerous species root readily in a slightly heated 

 propagating house. The greatest success is attained 

 when plants to provide the cuttings are grown under 

 glass. — The Garden. 



