-140 



HORTICULTURE 



May 29, 1920 



1597. The date of its introduction into 

 the United States is not Ivnown, but it 

 was a common garden plant here be- 

 fore the end of the eighteenth century 

 and may have been here much earlier. 

 There are specimens in the collection 

 raised a few years ago from seeds of 

 the wild Bulgarian plants. These are 

 interesting because it is possible by 

 comparing them w^ith modern Lilacs to 

 see the changes three centuries of selec- 

 tion and cultivation have made in these 

 plants. 



Hardly a week passes without a let- 

 ter addressed to the Arboretum asking 

 for the names of the best, or of the 

 best six or of the best twenty-five 

 Lilacs. There are now one hundred 

 and fifty named forms of the common 

 Lilac in the collection. They are all 

 or nearly all handsome plants, and no 

 two persons ever agree about their in- 

 dividual value. Some persons prefer 

 flowers of one color and other persons 

 prefer flowers of another color: some 

 persons like the Lilacs with double 

 flowers and others detest them. 



All the farms of the garden Lilac 

 have practically the same habit and 

 foliage, and the same inconspicuous 

 fruit; they all bloom freely nearly 

 every year, and breeding and selection 

 have not affected their perfume as it 

 has that of so many much "improved" 

 plants, like many of the modern Roses. 

 There is considerable variation in the 

 size of the individual flowers; the 

 double flowers open generally a little 

 later than the single flowers and last 

 longer, but there is really little differ- 

 ence in the time of flowering of all 

 these plants. The size of the flower- 

 cluster varies somewhat on the differ- 

 ent forms; it is larger on young plants 

 than on old ones, and it can always be 

 enlarged by severe pruning which in- 

 creases the vigor of the flower-bearing 

 branches. Choice therefore depends 

 on color, and really none of these 

 Lilacs are "best" for everybody; one 

 color or one shade is "best" for one 

 person and another color or another 

 shade is "best" for another person. 

 Many persons who visit the Arboretum 

 find the old Lilacs which have been 

 growing on Bussey Hill for nearly a 

 hundred years more beautiful than any 

 of Lemoine's recent creations because 

 they are the Lilacs which have long 

 been common in old New England 

 gardens and beloved by generations of 

 New Englanders. A choice of Lilacs 

 being largely a matter of taste in color 

 or of association, it is useless to ask 

 the Arboretum to make selections for 

 its correspondents. If persons want 

 Lilacs their only way to go about get- 

 ting them in an intelligent way is to 

 visit the Arboretum personally. 



EARLY AZALEAS. 



The first Azalea to open its flowers 

 this spring is the Korean Rhododen- 

 dron (all Azaleas are now called Rho- 

 dodendrons) poukhanense. This Aza- 

 lea, which is a common plant on the 

 bare mountain slopes in the neighbor- 

 hood of Seoul, was first raised at the 

 Arnold Arboretum in 1905 from seeds 

 collected in Korea by Mr. J. G. Jack 

 As it grows here this Azalea is a low, 

 wide, compact bush which never fails 

 to cover itself with its large, rose-pink 

 flowers. Some persons do not find 

 this color pleasing, but the flowers ot 

 no other Azalea in the collection have 

 such a strong and pleasant fragrance 

 The plants ripen good crops of seeds; 

 the seedlings are not difficult to raise 

 and there is no reason why this plant 

 should not be more common in gardens 

 than it is at present. 



The flower-buds of Rhododendron 

 (Azalea) Schlippenbachii open a few 

 days later than those of R. poukha- 

 nense. This Azalea grows on the ex- 

 posed grass-covered cliffs of the east 

 coast of Korea as a low bush with 

 branches clinging to the ground and 

 far northward as a tall shrub some- 

 times twelve or fifteen feet high un- 

 der trees in open or dense forests. It 

 grows further north than other Asi- 

 atic Azaleas, and only the North Amer- 

 ican Rhodora reaches a higher latitude 

 The flowers of this Azalea appear be- 

 fore the leaves and are pale pink 

 marked at the base of the upper 

 lobes of the corolla with dark spots and 

 are about three inches in diameter. 

 There can be little doubt of the hardi- 

 ness of this plant, for in Korea it grows 

 to its largest size where the winter 

 temperature often falls to 30 degrees 

 below zero Fahrenheit; and in the Ar- 

 boretum the flower-buds have not been 

 injured by the low temperature of re- 

 cent winters. There is every reason 

 to believe therefore that it will be pos- 

 sible to cultivate R. Schlippenbachii 

 anywhere in the northern states where 

 the soil is not impregnated with lime. 

 If this prediction proves true New 

 England will be able to add to its 

 gardens one of the most beautiful of 

 all the Azaleas. 



This plant, unfortunately, is still 

 rare in gardens. Although known to 

 Russian botanists as early as 1872, it 

 did . not reach England until twenty 

 years later when the late J. H. Veitch 

 sent to London a plant which he had 

 found in a nursery garden near 

 Tokyo. The plants in the Arboretum 

 were raised from seeds brought by Mr. 

 Jack from Korea, and at different times 

 a few plants have reached this coun- 

 try from the Yokohama Nursery. 



Fortunately Mr. Wilson during his 



journey in Korea in 1917 secured a 

 large quantity of the seeds of this 

 Azalea; this has been widely dis- 

 tributed by the Arboretum in the 

 United States and Europe and has pro- 

 duced several thousand plants. There 

 is reason to hope, therefore, that this 

 loveliest of the hardy Asiatic Azaleas 

 will become a common inhabitant of 

 northern gardens. 



THE STAG'S-HORN SUMACH. 



This species of Rhus succeeds well 

 under a variety of conditions, says a 

 writer in Gardening Illustrated, and 

 grows satisfactorily even where there 

 is a good deal of dust and dirt. Its 

 chief attraction centres in its long, pin- 

 nate leaves. These, on naturally- 

 grown plants, are usually from 15 

 inches to 18 inches long, but on vigor- 

 ous specimens they often approach a 

 length of 3 feet. Under ordinary cir- 

 cumstances it grows 8 feet to 15 feet 

 high, although it may exceed a height 

 of 20 feet, with a number of stiff, hairy, 

 rather gaunt branches, each one 

 crowned by a handsome head of leaves. 



Male and female flowers are borne by 

 different plants. Those of the male are 

 greenish and less showy than in the 

 female, which are borne many together 

 in dense, erect panicles from the points 

 of the shoots. The female flowers are 

 small and the ovary is covered by short 

 red hairs. During the process of seed 

 formation the red colour becomes more 

 intense, and the dense red erect pani- 

 cles each 4 inches to 6 inches long, are 

 very conspicuous amongst the leaves. 

 In addition to the male and female 

 plants there is a handsome cut-leaved 

 form of each, known under the varietal 

 name of laciniata. Both type and varie- 

 ty form excellent shrubs for planting 

 in large beds of rich soil in order to 

 obtain the largest possible leaves. 



Each plant is confined to a single 

 shoot, the result being leaves 3 feet or 

 more in length and a foot wide. They 

 are cut down as low as possible each 

 year, and as soon as new shoots appear 

 all except one are rubbed out. It is an 

 exhaustive method of cultivation, and 

 care should be taken to feed the plants 

 liberally. 



Propagation is easily effected by 

 root-cuttings, sections 4 inches long 

 and the thickness of a lead-pencil being 

 suitable. R. typhina is a native of 

 Eastern N. America, and has long been 

 an occupant of gardens. Fortunately, 

 it can be handled without leaving 

 behind the poisonous effects connected 

 with the handling of some species, 

 particularly R. Toxicodendron, the 

 Poison Ivy of Eastern N. America. 



