WOODY PLANTS FOR NEW ENGLAND 45 



PHELLODENDRON AMURENSE AMUR CORK-TREE 



A species which, except for the noticeably corky bark of older specimens, 

 may be considered to be of less value than P. sachalinense. 



PHELLODENDRON SACHALINENSE Saghalin Cork-Tree 



Though of no particular interest while young, this Asiatic species in its 

 later years forms a tall, broad-topped specimen with compound leaves which 

 turn a lemon-yellow in autumn. Its ability to resist trying growing conditions 

 makes it one of the few introduced trees of definite exotic aspect which seem 

 to be increasing in popularity. 



PHILADELPHUS Mock-Orange 



This is a large group which is much confused horticulturally now that so 

 many hybrid forms have appeared on the market. The following critical 

 selections give a working list which covers the range both as to floral and 

 vegetative characters. For an extended analysis, see the Arnold Arboretum 

 Bulletin of Popular Information for June 15, 1936. 



PHILADELPHUS GORONARIUS Sweet Mock-Orange 



The old-fashioned Mock-orange with single, fragrant, June flowers which 

 are ivory in color and something over an inch in diameter. A thin-twigged 

 shrub (up to ten feet or more) for mixed planting or undipped screens and 

 hedges. Shearing of tops will interfere with flowering unless done but once 

 a year and that in late June just after flowering. 



X PHILADELPHUS CYMOSUS, "NORMA" 



Also an upright shrub, but looser, less tall, and not as top-hardy. Its slightly 

 larger, fragrant white flowers in June are for the most part single; a few, double. 



X PHILADELPHUS LEMOINEI, "AVALANCHE" 



A hybrid of more drooping growth habit, with perhaps half the ultimate 

 height of P. coronarius. Relatively small, single, fragrant, white flowers in 

 June. Not always quite top-hardy in inland New England. 



X PHILADELPHUS MAXIMUS 



A tall, hardy, upright, relatively small-flowered, scentless, white hybrid 

 capable of reaching a height of thirty feet. Obviously nothing for the intimate 

 garden, but useful in some groupings. 



X PHILADELPHUS SPLENDENS 



A hybrid of rounded growth, making a large, well-furnished, mounded 

 growth-mass of somewhat greater ultimate height than P. coronarius. Its 

 scentless flowers are somewhat wider than those of P. coronarius and slightly 

 four-angled. 



X PHILADELPHUS VIRGINALIS, "VIRGINAL" 



An upright but not always too symmetrical plant of perhaps two-thirds 

 the ultimate height of P. coronarius. It has large, mildly fragrant and semi- 

 double flowers in June, with occasional bloom thereafter. Less hardy than 

 P. coronarius. 



Phlox bifida SAND Phlox 



A much-branched, woody-based, creeping Phlox which has hairy stems and 

 pale purple flowers with cleft petals. Useful in some rock gardening. A 

 totally different plant which is often erroneously sold under this name is 

 Ruellia ciliosa. 



