September 25, 1909 



HORTICULTURE, 



BOTANICAL 

 OAkDEN. 



lis 



New Davidias at Arnold Arboretum 



One of the most beautiful and remarkable trees re- 

 cently introduced is without doubt Davidia iiivolucrata 

 from Western China, a handsome tree reaching in its 

 native habitat a height of sixty to seventy feet and re- 

 sembling in foliage and habit a Linden tree. • Some pro- 

 nounce it the most beautiful aud striking object in the 

 Tegetable kingdom, when during its flowering time it is 

 studded with its large white floral bracts interspersed 

 between the bright green foliage. These bracts are the 

 chief ornamental feature of the tree and attain a length 

 of seven inches. The foliage also is handsome; the 

 bright green leaves are ovate in outline, from three to 

 six inches long, sharply serrate and long pointed and 

 borne on slender stalks. The flowers appear shortly 

 after the young leaves about the middle or end of May 

 at the end of short branchlets ; they consist of a globular 

 head of small individual flowers with long exserted sta- 

 mens bearing red anthers, similar to the flower heads of 

 our Buttonwood and are borne on a short stalk above the 

 two or sometimes three unequally large white bracts 

 oblong-ovate in outline, long pointed and usually more 

 or less serrate at the margin; the largest of the bracts 

 is from four to seven inches long and from two and a 

 half to four and a half inch broad, the second bract 

 is usually only half as long and the third if present still 

 smaller. The larger bract which is the lower one is 

 usually hanging straight down while the smaller and 

 upper one is bending over. The whole flower is borne 

 on a slender nodding stalk about two inches long. The 

 fruit presents no ornamental qualities: it is an ovoid 

 drupe, a little more than one inch in diameter with a 

 somewhat ridged surface, greenish, slightly tinged pur- 

 plish and somewhat bloomy. The tree itself is of broad 

 pyramidal habit and of comparatively rapid growth aver- 

 aging about two feet each year. Our plant at the Ar- 

 boretum has only been injured by the frost while young, 

 but during the last winter it has stood perfectly unin- 

 jured even to the tips of the branches. We may therefore 

 hope that this splendid tree will be hardy even in the 

 neighborhood of Boston, if planted in the right situation, 

 where the wood can be expected to ripen thoroughly be- 

 fore winter sets in. Propagation is effected by cuttings. 

 Eecently three species have been distinguished; the 

 original D. iiivolucrata has the leaves covered with a 

 silky pubescence on the under surface, D. Vilmoritiiaiia 

 has the leaves glabrous and glaucous beneath and in 

 D. laeta the leaves are yellowish green on the under side 

 and have shorter teeth. Our large plant belongs to D. 

 Vilmoriniana and is a cutting of the original plant 

 raised from seed in 1897 by M. L. de Vilmorin; this 

 plant wliicli I saw in 1906 at Les Barres, France, a few 

 weeks after it had flowered for the first time in cultiva- 

 tion, was then about fifteen feet high and a healthy and 

 vigorous looking tree. Of D. laeta we have only small 

 plants raised from seed collected recently by E. H. Wil- 

 son ; they have not yet been tried out of doors. The true 

 D. iiivolucrata which is supposed to be the hardiest of 

 the three species is said to be in cultivation at the 

 Yeitchian nurseries, but not yet represented at the Ar- 

 boretum. There seems to be no difference in regard 

 ^ to the flowers between the three species, but their distinc- 

 O^ tion will be of importance for horticultural purposes, if 

 ' they really should be of different hardiness. 



Among our native trees Davidia has its nearest rela- 

 tion in the Tupelo tree and belongs therefore to the fam- 

 p- ily of Cornaceae where Cornus florida presents a similar 

 fy case regarding the prominent development of bracts. 



The Avenue 



Without having any wish to substitute the essential 

 irregularity of modern landscape for the style of Le 

 Notre, which became the fashion over the whole of Eu- 

 rope in the eighteenth century, when, as Pope satirically 

 wrote in a couplet, so often quoted: 



"Grove nods at grove, each alley has a brother, 

 And half the platform just reflects the other." 



When every villa and suburban house had its small 

 s)'mmetrical garden it is not to be wondered at that 

 universal monotony of this kind of design should create 

 a feeling of aversion in the beholder, and at length, that, 



"Tired of the scenes parterres and fountains yield, 



We find at last he better likes a field," 



and it was only natural that the formal style should have 

 given place to one more in consonance with nature. Much 

 of this ancient style in garden laying out remains to the 

 present day as seen at Versailles, Schoubrunn and Ken- 

 sington Gardens, Ashridge, and many other places in the 

 British Isles. In old times the drive to the house was 

 an avenue through the park surrounding the same. 

 Sometimes the double or single line of trees was 

 adopted; with the object of forming a better kind of 

 shelter trees were planted "quincunx" fashion. 



As the eagerness to adopt this mode of planting could 

 not always wait for the slow growth of trees, where old 

 woods were in existence, these were cut through in 

 straight lines, and in the form of stars and pates d'oie 

 (goose feet). Tired of the uniformity of straight lines, 

 serpentine methods of planting the trees and forming 

 rondeaux at widely separated points in the avenue were 

 next in fashion; and sometimes trees were planted in 

 groups with the roadway at some distance away on either 

 hand. This last is not a bad method in climates with 

 a heavy rainfall as it allows the sun to reach the road, 

 and it is thereby kept fairly dry, and the shade from the 

 nearest row of trees is very grateful to the pedestrian 

 in hot weather, whilst the multiple rows of trees afford 

 shelter from the wind. And a drive thus formed may 

 serve as a screen of some objectionable feature in the 

 landscape. On some large estates in England and Scot- 

 land, where timber is cultivated for use as such, and not 

 for the preservation of game, the planting is so ar- 

 ranged for the production of straight timber — that is, by 

 what is called close cover overhead — that the formation 

 of avenues is a matter of necessity, and it usually con- 

 sists of the same kind of trees as those of which the 

 forest is formed. It may be oak, beech, hornbeam — a 

 favorite wood used for fuel in parts where coal is dear, 

 and peat not obtainable; ash, elm, chestnut (sweet), 

 maple, limes and willow: or it may be that conifers are 

 planted. All or any of these, if at the sides of an ave- 

 nue, by reason of the absence of crowding at the sides 

 become furnished with branches down at the ground 

 level, forming more presentable objects, if less commer- 

 cially valuable than the rest of the trees composing the 

 forest. Sometimes a proprietor of woodland will plant 

 the sides of an avenue with trees of a distinctly orna- 

 mental character; and for this purpose his choice is a 

 wide one. He would do wisely to plant the flne foliaged 

 Quercits palustris, Q. rubra, Q. tinctoria, etc. Other 

 species of trees which might be planted at tire sides 

 of forest or woodland avenues and drives are 

 Acer Colchicum rubrtun, A. dasycarpum, A. planta- 

 noides. and A. rul)rum, trees in all cases of sym- 

 metrical growth and moderate height. The Pavias with 

 handsome spikes of flowers, Aesculus Hippocastaneum, 

 Ailanthus glandulosa. Betula of species, Catalpa speci- 

 osa, Ulmus montana. U. m. vegeta and several more. 



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