June 20. 1908 



HORTICULTURE 



813 



Notes from the Arnold Arboretum 



As the last of tlie sliowv Ericaceoiis; slirubs the iloun- 

 tain Laiarel is now in bloom and the large group on 

 Hemlock Hill is a mass of pink flowers shown oft' to the 

 greatest advantage by the dark background. The 

 Mountain Laurel must certainly be considered as one 

 of our most beautiful native shrubs and is as effective 

 when massed in large groups as when planted singly as 

 undergrowth on the borders of woods. A very fine va- 

 riety is Kalmia latifolia var. ruhra with deep pink flow- 

 ers, while the white variety var. alba is perhaps less 

 handsome than the common light pink form. Very 

 peculiar is A', latifolia var. monstruosa which has the 

 corolla divided into five narrow petals; the flower clus- 

 ters have therefore a feathery appearance and the whole 

 shrub looks very distinct from the ordinary Mountain 

 Laurel. There is also a low small leaved variety called 

 var. myrtifolia which is pretty as a small evergreen 

 shrub but flowers not at all or very sjDaringly. 



The brilliant Rhododendron mlcndulaccum is now 

 passing and the less showy R. arhorescens with pure 

 white, very fragrant flowers is beginning to bloom and 

 this species will be followed soon by the similar R. vis- 

 cosuin, the Swamp Honeysuckle. 



Most of the Mock Oranges are now in bloom and par- 

 ticularly attractive are the many varieties of Philadel- 

 plius Lcmoinci. One of the best is Avalanche with 

 gracefully spreading and arching branches covered 

 their whole length with showy white flowers; it is one 

 of the latest to bloom. Gerbe de neige is .similar, but 

 less graceful with larger flowers opening earlier. Hand- 

 some varieties with upright branches and single flowers 

 are Candelahrc, Mont Blanc and the somewhat later 

 blooming Pavilion Blanc, while Bouquet Blanc has large 

 semidouble flowers. I'hiladelphus niicrophyllufi, one of 

 the parents of P. Lenfioinei, is an attractive little shrub 

 -with small myrtle-like foliage and small but deliciously 

 fragrant flowers; it flowers later tiian the hybrids. Per- 

 haps the most beautiful of the native species is P. ino- 

 dorns, a compact shrub with lustrous foliage and large 

 cup-shaped flowers solitary along the branches. Pliila- 

 delphus grandifiorus which is often confounded with 

 the preceding species, is a higher shrub with duller and 

 larger foliage and flowers apparently less profusely. 



The tree-like Japanese Lilac, Syringa Japonica, is 

 now in full bloom and the two trees in the Arboretum 

 are very conspicuous objects studded with their immense 

 panicles of creamy white flowers. The similar but 

 shrubby S. amurensis flowers somewhat earlier and is 

 already fading. 



The Yellow-wood, Cladrastis li)ictoria, flowers this 

 year profusely: with its large droo])ing panicles of white 

 fragrant flowers it looks very chanuing and is particu- 

 larly suited for planting as a solitaiy tree on the lawn: 

 its chief drawback is that it doss not flower every year. 



A shrub of striking l)eauly is Sh/ra.r japonica when 

 its spreading branches aie loaded with the drooping 

 white flowers: it is the hardiest of the Styrax, but 

 requires licre a sheltered position. 



The handsomest of the Privets hardy in this vicinity 

 is certainly Lignstrnni Ihoia witli its gracefully arching 

 liranclips covered tliciv wliole length with small droop- 



ing clusters of white flowers. Also L. acuminatum (L. 

 ciliatum, L. medium) is an attractive shrub when in 

 bloom, though not as handsome as L. Ibota; it is of 

 more upright haljit with spreading branches bearing 

 numerous small panicles of white flowers. 



Among the later flowering Dogwoods Cornus panicu- 

 lata (C. candidissima) is one of the prettiest in bloom; 

 it is a clean shrub of graceful habit and well adapted 

 for borders of shnibberies. Another good Dogwood is 

 Cornus circinnata which is now conspicuous with its 

 numerous clusters of creamy white flowers. 



Similar to the latter in habit is Viburnum dentatum, 

 also a native shrub, but showier than this is the Jap- 

 anese V. dilatatum which has much larger corymbs of 

 white flowers followed in autumn by scarlet fruits. An 

 interesting native species is V. molle which is now flow- 

 ering for the first time in the Arboretum; it was first 

 discovered more than 100 years ago by the elder 

 Michaux, but was not found again until fifteen years 

 ago and described then as a new species, V. Demetri- 

 onis, because the name V. mollo had been in the mean- 

 while applied erroneously to another more common 

 species: the true T'. moUe is still very rare in cultivation 

 and as our plants are yet small, nothing definite can be 

 said about its ornamental qualities. 



Arnold Arhoretmii, Juniaira Plain, Mass. 



The Hardy Rhododendron Ques- 

 tion 



I was delighted to read Mr. Ivoehler's interesting com- 

 munication in HoRTicuLTCEE on the above topic. I 

 naturally differ from him in many of his remarks, but 

 this I am sure is pardonable, as gardeners have oft 

 found that their experience, scientific deductions, and 

 "logical conclusions" have not always been unanimous. 

 But then criticism is an essential feature in all things 

 pertaining to the improvement and enlightenment of 

 our profession, or in other words, it is the separator 

 which takes the impossible from the possible and leaves 

 us the workable idea. 



When Mr. Koehler writes about Rhododendrons I 

 receive what he says with interest and respex;t, because 

 I feel certain that he has given the subject his careful 

 attention for many years, and accordingly writes ex- 

 actly what his experience has led him to believe as being 

 correct. But when Mr. Koehler gets behind a rhodo- 

 dendron bush and fires a few illogical deductions at me 

 I am tempted to again take up mv pen in an effort to 

 bring him back to the point. The point when exam- 

 ined closely has rather the appearance of two points — 

 horn points of a dilemma. 



Here then is the dilemma. A list of twelve Ehodo- 

 dendrons were given by me as being suitable for plant- 

 ing, under suitable conditions in New England. Those 

 varieties, I may say, are all at the present time doing 

 well at various establishments, to my knowledge, both 

 in the vicinity of Boston and Xew York. Mr. Koehler 

 on the other hand, with dogmatic assurance, and the 

 true teutonic spirit of finality, classed my list as an 

 undesirable mixture of facts and tenninological inexacti- 

 tudes. The question, therefore, devolves into one of 

 individuals, and must be treated accordingly. T shall 

 tlierefore endeavor to show ^Ir. Koelder a reason whj' 



