Populus
| {{{name}}} LATINNAME
|
'
| ||||||||||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
|
| |||||||||||||||||||||||||||||||||||||||
| |||||||||||||||||||||||||||||||||||||||||
| Standard Cyclopedia of Horticulture |
|---|
|
Populus (ancient Latin name, of disputed origin). Salicaceae. Poplar. Aspen. Cottonwood. Soft- wooded trees of rapid growth, some kinds of which are much planted on roadsides and in grounds, particularly when quick results are desired. The poplars are dioecious, with both staminate and pistillate flowers naked but from a cup-shaped disk, and in slender mostly drooping precocious catkins in which the subtending scales are toothed, cut or cleft at the apex: stamens few or many, usually numerous, on distinct filaments: pistillate fls. with mostly a single 1-loculed mostly sessile ovary with short style and 2-4 often lobed long stigmas: fr. a small 2-4-valved caps., containing cottony seeds, the mature catkin sometimes with a necklace-like or moniliform character: lvs. alternate, stalked, mostly broad: buds scaly, often resinous.—Species probably about 35-40, in the northern hemisphere, mostly extra-tropical, although very many more than this have been described, some of them being hybrids. The poplar of lumbermen is the tulip tree. (See Liriodendron.) Botanically the poplars comprise a most bewildering group, and there is wide divergence of opinion and practice as to the limits and names of species. Many of the cultivated forms are assumed to be hybrids, but the origin of most of them, so far as parentage is concerned, can be little more than conjectured. It is likely that seedlings of some of these hybrids break up into forms much resembling the parents, and thereby still further contribute to the bewilderment. The trees being dioecious, the herbarium specimens may not represent both sexes; as the catkins appear in advance of the foliage, the specimens may not represent the same plant or type; the foliage is very various, sometimes even on the same tree, and specimens are likely to be taken from the lower part of large trees where the leaves are small or from the terminal shoots of young trees on which the leaves are large and have a different character. Of some kinds only one sex is known. The habit of growth is also very characteristic even in species or forms on which the foliage is very similar, but this character is of course not represented in botanical specimens. It will be seen, therefore, that the usual herbarium collection may not have full value in the determination of species. There is naturally a tendency to place great stress on leaf-forms in the description of species, even though in some groups practically the whole range of forms may be found on single trees. These difficulties are particularly marked in this country in the P. deltoides-angulata group. With regard to the variability of the leaves of Popu- lus, Schneider writes in "Plantae Wilsonianae," "it is helpful to keep the following in mind. L. A. Dode was the first who clearly described the variation of the leaves according to the age of the plants, the position of the branches, and the climatic and other conditions under which they were produced. ... I think it sufficient if we distinguish three different kinds of leaves: (1) the leaves of the offshoots or suckers (folia turionum radicalium); (2) the leaves of the normal but not the vigorous shoots of the young plants (folia ramorum [sed non turionum] plantae juvenilis); and (3) the leaves of the old trees (folia arboris adultae; fructiferae). The leaves of the third kind we usually find at the ends of vigorous branches of young plants when they are growing well and becoming mature. If we compare leaves of different species it is necessary to be very careful only to compare the same kinds of leaves." What has been said about the dependence on leaf- characters in descriptions applies also to the horticultural description; it is much needed that the cultivated poplars shall be studied with the purpose to correlate 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 habitations, as do the introduced tree willows, and that they have been confused with the native kinds. There appear to be few important growing collections of poplars in this country, nor have the important cultivated examples in different parts been looked up and studied. Many of the European nursery forms have been introduced here and there; but for ornamental 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 sufficient attention in North America. Some of the first-generation hybrids are remarkably vigorous. The Russian poplars are undoubtedly of several kinds, mostly, apparently, 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 Manitoba. 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 in 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 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 hardwood cuttings, as do willows and currants. The weeping varieties are grafted head-high on erect kinds, P. gran- 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 temporary 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 maintenance of the stronger forests. In this way it probably 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 unfavorable 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 ornamental grounds is the production of minor or secondary effects. As a rule, they are less adapted to isolated planting 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 foliage. 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 particularly 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 free 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 their 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 rustle with the lightest movement of air. The ripple of its foliage recalls the play of wavelets on a pebbly shore. The day is never so dark but the cottonwood reflects a flood of light. One should take care, however, to plant only the staminate tree, for the "cotton" of the seeds is very disagreeable on lawns and about dwellings when carried by the wind. In the plains and mountain states, the western cottonwood (P. Sargentii) is a characteristic tree. Some of the forms of the black poplar of Europe are especially satisfactory for the production of lively effects in planting. Of these, one of the most distinct is the form known to nurserymen as Populus elegans. It has a most pleasing light and tremulous foliage, the effect of which is heightened by a twiggy character of growth and a reddish cast to the leaf-stalks and young shoots. It is an elegant tree, and well adapted to planting in front of heavier foliage in the most conspicuous part of the grounds. Some of the silver- or white-leaved poplars produce the most striking contrasts of foliage, especially if set near darker trees. Bolles' poplar (Populus Bolleana of the nurseries) is one of the best of these trees. Its habit is something like that of the Lombardy. The upper surface of the deeply lobed leaves is dark dull green, while the under surface is almost snowy white. Such emphatic trees as this should usually be partially obscured by planting them amongst other trees so that they appear to mix with the other foliage, or else they should be seen at some distance. Other varieties of the common white poplar or abele are frequently useful, although most of them sprout badly and may become a nuisance. The Lombardy poplar (P. nigra var. italica) is probably the most striking and distinct tree that is suited to planting in the North. As single specimens scattered here and there in mixed plantings, or when seen over or behind buildings, it may be most picturesque and satisfactory; but the tendency is to plant it too freely. The very fact that it is emphatic is the reason why it should be planted sparingly when artistic effects are desired. The catkins of poplars, particularly the staminate ones, are usually attractive, as they appear in early spring; but they are of short duration. Fig. 3130. The following sketch includes all the poplars known to be offered by American nurserymen or to be subjects of rather general planting, together with exotic forms that are likely to appear in this country. For literature, see Wesmael, DC. Prodr. 16, pt. 2, pp. 323- 31: Sargent, Silva of North America, vol. 9 (quoted below as S.S.). A very recent careful treatment of the poplars appears in Volume VII of Elwes & Henry, Trees of Great Britain and Ireland;" from this work some of the following characterization is drawn. Subsequently, the black poplars (P. nigra-deltoides group) have been worked over by Henry in Transactions of the Royal Scottish Arboricultural Society, 30, pt. 1. Discussions of the genus of recent date will be found in C.K.Schneider, "Handbuch der Laubholzkunde"(1906)and Dode in Memoires Societe d'Histoire Naturelle d'Autun (1905).For an account in "Plantae Wilsonianae,"Vol.III. Index acuminata, 19. euxylon, 14b. pendula 1, 2, 4, 5, 6. adenopoda, 4. Fargesii, 15. Petroswkyana, 28d. afghanica, 8. fastigiata 8. plantierensis, 8. alba, 1, 2, 3. fortissima, 18. pruinosa, 29. Andre waii. 12a. Fremontii, 9, 10. Przewilskii, 24. angulata, 11,13, 14.Freynii, 4. pseudobalsamifera, 28a. angulosa, 14 note. generosa, 14g. pseudograndidentata,4. 5. angustifolia, 18. glabrata, 3. pyramidalis, 1,4, 8. arembergiana, 1. globosa, 1. pyramidata. 8. argentea, 1. graeca, 5, 6. Rasumowskyana, 28c. ariana, 29. grandidentata, 5. regenerata, 14e. atheniensis, 6. hastata, 17. Richardii, 1. aurea, 6, 11. helvetica, 14a. robusta, 14d Baileyana, 21. heterophylla, 16. rotundifolia, 7. balsamifera, 17, Henryana, 14c. salicifolia, 26. 20,24, 25, 27. hudsonica, 8. Sargentii. 12. berolinensis, 28a. hybrida, 2. serotina. 14a. Besseyana, 11. intermedia, 24. sibirica, 24. betulifolia, 8. italica, 8. Sieboldii, 7. Bogueana, 2. Jackii, 21. Silvestrii, 4. Bolleana, 1. lasiocarpa, 15. sinensis, 8. Brandegeei, 1. laurifolia, 24,25, Steiniana, 2. brevifolia, 27. 26,27. suaveolens, 24. canadensis, 14 note. Lindleyana, 26. subintegerrima, 1. candicans, 17, 20. Litwinowiana, 29. szechuanica, 24. canescens, 2, 8. Lloydii, 14f Tacamahaca, 20. Carolina. 14 note. MacDougalii, 10. therestina, 8. caroliniensis,14 note. macranthela, 7. tomentosa, 3. caroliniana, 14 note. macrophylla, 14 note, tremula, 4. cercidiphylla,6. 20. tremuloidea, 6. certinensis, 28a. marilandica, 14b trichocarpa, 28. charkowiensis,8. Maximo wiczii, 23. triloba, 1. ciliata, 17. megaleuce, 2. tristis, 22. coloradensis, 19. mexicana, 10. Tweedyi, 19. crispa, 26. Michauxii, 17. typica, 8. Davidiana, 4. microcarpa, 7. Van Geertii, 11. deltoidea, 11. missouriensis. 11, 14 Viadri, 8. deltoides, 11, 12. note. villosa, 4. Denhardtiorum,29. monilifera, 11, 12, viminalis, 26. denudata, 3. 14 note. virginiana, 14 note. dilatata, 8. monticola, 1. vistulensis, 8. diversifolia, 29. Morisetiona, 1. Wilaonii, 15. Dudouxiana, 7. nigra, 8. Wislizenii, 10. Dudleyi, 26. nivea, 1. Wobstii, 28b. elegans 8. Nolestii, 28c. yunnanensis, 24. Eucalyptus, 14e. occidentalis, 12. Eugenei, 14. ontariensis, 20. euphratica, 29. pekinensis, 3. For the purposes of this popular treatment, the species of Populus may be thrown into six groups: I. The white poplars; Nos. 1-3. II. The aspens; Nos. 4-7. III. The black poplars and cottonwoods; Nos. 8-14. IV. The large-leaved poplars and cottonwoods; Nos.15, 16. V. The balsam poplars and tacamahacs; Nos. 17-28. VI. The variable-leaved poplars; No. 29. I. White Poplars. Lvs. mostly strongly angled or lobed and broader than ovate in shape, the mature lvs, on the long or verdurous shoots usually white- tomentose or gray-canescent beneath (at least in the cult, forms), lvs. on the short or small shoots often becoming glabrous or nearly so and often of different shape from those on the strong-growing shoots; petiole usually cylindrical: terminal buds relatively small and not glutinous. CH
|
Cultivation
- Do you have cultivation info on this plant? Edit this section!
Propagation
- Do you have propagation info on this plant? Edit this section!
Pests and diseases
- Do you have pest and disease info on this plant? Edit this section!
Species
Gallery
If you have a photo of this plant, please upload it! Plus, there may be other photos available for you to add.
photo 1
photo 2
photo 3
References
- Standard Cyclopedia of Horticulture, by L. H. Bailey, MacMillan Co., 1963
