2754 



POPULUS 



POPULUS 



What has been said about the dependence on leaf- 

 characters in descriptions applies also to the horti- 

 cultural description; it is much needed that the culti- 

 vated poplars shall be studied with the purpose to corre- 

 late the characters of habit, leaves, buds, twigs, bark, 

 flowers, and fruit. 



Probably some of the difficulty in distinguishing 

 native species of Populus is due to the fact that we have 

 not recognized the presence of European or other 

 hybrids in this country. It is not unlikely that some 

 of these forms appear even in places remote from habita- 

 tions, as do the .introduced tree willows, and that they 

 have been confused with the native kinds. 



There appear to be few important growing collec- 

 tions of poplars in this country, nor have the impor- 

 tant cultivated examples in different parts been looked 

 up and studied. Many of the European nursery forms 

 have been introduced here and there; but for ornamen- 

 tal planting practically only two kinds are much called 

 for, the Lombardy and the so-called Carolina, with 

 "Russian poplars" and "Norway poplars" in the 

 prairie and plains 

 country. This is a 

 pity, seeing that some 

 of the forms are most 

 interesting in habit 

 and foliage, and in 

 the red coloring of 

 petioles and midribs, 

 combined with other 

 good features. The 

 hybrid poplars have 

 not been given suffi- 

 cient attention in 

 North America. Some 

 of the first-genera- 

 tion hybrids are re- 

 markably vigorous. 

 The Russian poplars 

 are undoubtedly of 

 several kinds, mostly, appar- 

 ently, forms or hybrids of P. 

 balsamifera allies. A very large 

 collection of Asiatic poplars was 

 made at the botanic gardens at 

 St. Petersburg and also at the 

 agricultural college at Moscow. 

 The late J. L. Budd introduced 

 many of these forms and they 

 have become widely distributed 

 in the prairie regions. It would 

 not be strange if substitutions 

 had been made in the course of 

 time. 



The Norway poplar of the 

 interior region is very like P. 



Sargentii in foliage, but it holds its leaves three weeks 

 later in autumn than the native cottonwood and the 

 central trunk does not break up so quickly, thereby 

 making a better timber tree; it is a very rapid grower. 

 It has proved to be a very valuable tree for Minnesota 

 and the Dakotas and other parts, and is hardy in Mani- 

 toba. On account of its very rapid growth and the 

 straight strong trunk, it has been called the "Sudden 

 Sawlog poplar." It appears to have been introduced 

 into North America from Russia by Budd, and is said 

 to have been discovered on the eastern slope of the 

 Altai Mountains. It was disseminated in part hi this 

 country by Norwegian settlers and thereby got the 

 name of Norway poplar. Its botanical position or 

 name is undetermined. 



Poplars of various kinds are considerably planted on 

 the prairies and plains and form characteristic features 

 on the landscape. Many of them withstand the trying 

 climatic conditions and also grow very rapidly. The 

 many kinds of cultivated poplars, which have been 



3126. Populus canescens above, 

 and P. alba var. pyramidalis (P. 

 Bolleana). (X 1 A) 



largely introduced or tried in these regions, stretching 

 into Canada, need careful study by the systematist. 

 They are particularly numerous in the tacamahac or 

 balsam-poplar group and are not well understood. In 

 the irrigated regions of the Rocky Mountain country, 

 the Lombardy poplar has long been a familiar object 

 along ditches and thoroughfares. 



The poplars are amongst the easiest of all trees to 

 propagate and to grow. They come readily from hard- 

 wood cuttings, as do willows and currants. The weeping 

 varieties are grafted head-high on erect kinds, P. gran- 

 didentata or its derivatives apparently being used as a 

 stock. Poplars thrive in almost any soil, although the 

 cottonwood is most at home in lowlands and along 

 streams, at least in the East. For shelter-belts they are 

 very useful because of rapid growth and great hardiness. 

 In Europe, where fagots and other similar materials 

 are desired, poplars are often headed-back severely or 

 pollarded, but this practice is very little known in 

 North America. The poplars are also useful for tem- 

 porary shelter for other trees and bushes. In this 

 respect the common aspen (P. tremuloides) is a valuable 

 tree in the reforestation of American lands. It springs 

 up quickly in clearings, and during its comparatively 

 short life holds the soil and protects other vegetation 

 and finally contributes its own substance to the main- 

 tenance of the stronger forests. In this way it prob- 

 ably has exerted an effect upon the configuration of our 

 forest areas and upon the fertility of the land from 

 remote time. The same qualities make it valuable, in 

 many cases, in extensive ornamental plantings. 



The fault in the planting of poplars is the tendency 

 to plant too many and to allow them to give character 

 to the place. About summer resorts, for example, 

 poplars and willows are used much too freely. They 

 give the place a look of cheapness and temporariness. 

 They are planted in such places because 

 they grow rapidly and thrive in unfavor- 

 able conditions; but it is better to use 

 them for temporary effects, allowing 

 better trees, that are planted with them, 

 gradually to take their places. The 

 legitimate common use of poplars in orna- 

 mental grounds is the production of 

 minor or secondary effects. As a rule, 

 they are less adapted to isolated plant- 

 ing as specimen trees than to use in com- 

 position, as parts of general groups of 

 trees, where their characters will serve 

 to break the monotony of heavier foli- 

 age. The poplars are "gay" trees, as a 

 rule, especially those, like the aspens, 

 that have a trembling foliage. Their 

 leaves are bright and the tops thin. A 

 few of them in judicious positions give 

 a place a sprightly air. This is particu- 

 larly true of the common aspen, P. tremuloides, of the 

 woods. Its light twinkling foliage and silver-gray 

 limbs are always cheering and its autumn color is one 

 of the purest golden yellows of our landscapes. It is 

 well to have a tree of it standing in front of a group of 

 maples or evergreens. Its whole expression is then one 

 of familiarity. 



On the other hand, the poplars have then" interest as 

 specimen trees as distinctly as do other kinds of trees, 

 but one seldom sees well-grown mature examples. 

 The age characters of some kinds of poplars, both in 

 structure and in bark, are as interesting as are those 

 of maples and oaks or other trees. Of many of the 

 planted poplars, old specimens are practically unknown 

 to the public. 



The cottonwood (P. deltoides) is one of the best 

 poplars for permanent planting. It makes a noble tree, 

 of durable and substantial appearance. But like the 

 aspen, it is cheerful and restive. One is not moved to 

 lie under it, as one is under a maple or an oak. Its leaves 



