216
BULLETIN 68.
in the spring, in the same manner as practiced with grape cuttings
in the West. It grafts readily on several of our common poplars
and on strong growing kinds its growth is considerably increased.
"P. alba var. argentea closely resembles the species but has
heavier down on the underside, and is rather more spreading in
habit, and is more easily propagated from cuttings."
II. THE CULTIVATED SPECIES OF POPLARS.
The following catalogue attempts to refer the nursery and horti-
cultural names of pop-
lars to their proper
botanical species, and
it includes various
notes upon the horti-
cultural values of the
different types. The
genus appears to be
much confused
amongst nurserymen,
and the perplexity has been
increased by the arrival of the
Russian varieties. In the pre-
paration of this monographic list,
I have received the greatest aid
from the collection of EHwanger &
Barry, which has been freely placed at
my disposal. The winter twigs are often
useful in distinguishing the species, and I
have therefore inserted a photograph (Fig. i)
of some of them.
GROUP I. BALSAM POPLARS, or those with
resinous-sticky more or less elongated buds.
i. Populus angfustifolia (James, Long's
Exped. i-497). YELLOW or BLACK POPLAR of
the west. Fig. 2. A pyramidal small tree with
ovate-lanceolate willow-like leaves and cylindri-
cal twigs, native from South Dakota west and south. It is spar-
ingly cultivated. It is a tree of good habit and soft clear green
2. Populus angus-
tifolia. (% nat.
size. )
THE CULTIVATED POPLARS.
217
foliage, and is worth attention in the composition of groups.
May be confounded with Populusbalsamifera, var. viminalis, which
see. The slender, cylindrical winter twigs with small buds (e, fig.i)
are very different from the heavier and angled shoots, with coarse
buds, of the other (k, fig. i).
2. Populus balsamifera (Linnaeus, Sp. PI. 1034 ( 1 753)-
BALSAM POPLAR, TACMAHAC. Fig. 3. A tall upright tree, with
a nairow straight top, growing in woods and along streams in the
Northernmost States, and also in Northern Europe and Asia.
Leaves thick and firm,
erect, whitened beneath,
usually smaller than in
most other poplars of this
Group : in shape ovate-
lanceolate or oval, taper-
ing towards the top and
sometimes at the base,
finely and obtusely
toothed. Young branches
nearly or quite cylindri-
cal.
The native form is
occasionally seen about
farm buildings and road-
sides, where it makes a
durable and pleasant
tree ; but it is most too stiff for the pleasantest effects and too
narrow for the best shade. The dull whiteness of the under
side of the leaves affords a pleasant variety and contrast in its
foliage, and the fragrance of the resinous buds in spring is pleas-
ant to most persons. It is a desirable tree for occasional plant-
ing, but, like the Lombardy, it generally appears to best advant-
age when placed amongst other trees. It is a hardier tree than
the Lombardy, and does not run quickly to such extravagant
heights. In cultivation from Russian sources, it is known as
Nos. 1 6 and 26 Voronesh and 32 Riga. Fig. 3 shows ordinary
foliage (16 Voronesh) about half size.
The balsam poplar is probably the most variable of poplars.
j. Fopulus balsamifera (16 Voronesh.}
nat. size.}
218
BULLETIN 68.
In cultivation in this country it is represented by no less than
three well marked botanical varieties, differing from the species
and from each other in the habit of growth, shape and color of
leaves and character of twigs.
P. balsamifera variety intermedia (Loudon, Encyc. of Trees
and Shrubs, 830 (1842). P. laurifolia of American horticulturists,
not of botanists. P. Sibirica pyramidalis, of horticulturists).
Fig. 4. A com-
paratively slow
growing tree of
close upright
habit, from
Northern Eur-
ope, where it is
used as a street
tree. The leaves
are very thick
and hard, finely
nat. serrate, oval in
outline, and
prominently whitened beneath, and they are commonly rather small
for this group. Twigs hard and cylindrical. It is considered to
be a valuable tree for hot and dry interior climates ; and it also
has distinct merit for ornamental planting. It eventually becomes
a large tree. The Populus laurifolia and P. Sibirica pyramidalis
of American nurserymen are, so far as I can determine, only minor
variations of one varietal type. All these trees are amongst
the recent introductions of Russian poplars.
P. balsamifera var. viminalis, (Loudon, Encyc. 830, t. 1510.
P. viminalis, L,odd. Cat. (1836). P. Lindleyana, Booth, Rev.
Hort. 1867, 380. P. salicifolia, P. crispa, P. Dudleyi, and P.
pyramidalis suaveolens of horticulturists. Also sometimes called
P. laurifolia]. Fig. 5. A tree of only moderate and rather slen-
der growth, with a partial weeping habit when old ; native to
northern Europe. It is at once distinguished from other forms of
Populus balsamifera by its sharply angled twigs (k, fig. i), and
broad-lanceolate willow-like leaves which are finely serrate and
often crinkled-margined.
balsamifera variety intermedia,
size.
THE CULTIVATED POPLARS.
219
I am inclined to regard this as a distinct species from the balsam
poplar. If it should be elevated to specific rank, it would be
difficult to determine a correct name for it. Its first specific name
is evidently L,oddige's, Populus
viminalis, but that was only a
catalogue name and therefore
could not hold under the recent
rules of botanical nomenclature.
Populus Lindleyana was regu-
larly published in 1867, but this
name appears to have been used
by horticulturists for a form of
the cotton wood. The other
names which it bears are used only
by gardeners and nurserymen.
4. Populus balsamifera var. viminalis. (}4 nat. size.}
But however much doubt may attach to the botanical position
of this small tree, it is valuable to planters if a tree of willow-
like aspect but with more pronounced color effects and greater
size and durability is desired. It is very like the native Populus
angustifolia, which it represents in Europe, but is readily distin-
guished by its angled or furrowed stems, and less tapering and
220
BULLETIN 68.
crisped leaves which are conspicuously finely reticulated and
whitened beneath. The color of its foliage is a grayish green,
and in this respect it affords a contrast to the native species. The
native seems to be rather the better tree of the two, although the
viminalis has a more striking appearance.
P. balsamifera, var.
latifolia (London, En-
cyc. 830. P. Nolestii and
P. Wobsky of horticultur-
ists). Fig. 6. This var-
iety includes Asiatic
forms with ovate or cord-
ate-ovate rather blunt
pointed leaves, cylin-
drical twigs (or slightly
ridged on strong shoots)
(g, fig. i ) and the gen-
eral habit of the balsam
poplar. The leaves are
usually large and thick,
shining green above and
dull white beneath, in
shape and texture some-
what like the next species (P. candicans}. The Nolestii poplar is
now sold by Eastern nurserymen as an ornamental tree. Its
strong habit and dark foliage adapt it admirably to planting
near the rear borders of grounds. The Wobsky poplar is one
of the recent Russian introductions, with somewhat the habit of
a cherry tree, and is much prized in the northwest. The Rasu-
movskoe poplar appears to be of the same type.
3. Populus candicans(Aiton, Hort. Kew. iii. 406. P. bal-
samifera, var. candicans, Gray, Manual, 2nd ed. 419. P. Ontari en-
sis and P. macrophylla of European horticulturists). BALM OF
GILEAD. Fig. on title page. A strong-growing spreading native
tree, frequently planted, and esteemed for its vigor and hardiness
and the resinous fragrance of its large buds in spring-time. The
leaves are broad and heart-shaped, green above and veiny and rusty-
white beneath, and the leaf-stalk is usually hairy and somewhat
6. Populus balsamifera var. latifolia.
not. size. )
THE CULTIVATED POPLARS. 221
flattened. It is very different from the balsam poplar in method
of growth, as it has none of the pyramidal or spire-like tendency
of that species, but usually makes a broad and irregularly spread-
ing top. While the tree is common in cultivation, it is rare wild.
In the early days, however, it was found in very large trees in
Michigan and other western states, and was used for sawing
timber ; and isolated natural groves of it are still occasionally
seen.* The balm of gilead makes a good street tree, and is per-
haps the best of the poplars for shade. Well grown trees have
the darkest and richest foliage of any common poplar, and this
character makes the tree valuable in heavy groups about the
borders of a place. The top is liable to become open and
broken with age, however, and the tree often sprouts profusely.
It is not well adapted to smoky and dusty locations, as
it soon becomes grimmy. It was used to good purpose in the
lagoon borders of the World's Fair, where its exuberant growth
and stiff heavy leaves gave a massive effect. The illustration
upon the title-page shows a spray of the balm of gilead, one-
third natural size.
4. Populus Simonii (Carriere, Rev. Hort. 1867, 360).
A strong strict tree from China, whence it was introduced into
France about 1861 by M. E- Simon. It is now very sparingly
planted in this country, but its merits are scarcely known. In
foliage it is much like the next species (P. laurifolia). Its leaves
differ from those of the balm of gilead in having a rounded or
tapering base and much finer teeth, but otherwise they are much
alike. The shoots are reddish brown and spotted, and deeply
grooved. Professor Craig, of the Central Experimental Farm,
Ottawa, Ontario, who has had considerable experience with the
tree, writes as follows concerning it :
' ' The tree in nursery and on the lawn is a very strong
grower, with large ovate leaves, having the characteristic five-
sided shoots of these Russian poplars. It grows very rapidly,
making a growth of from six to ten feet per annum. I have not
known it to winter kill either here or in Manitoba. It can
hardly be termed strikingly ornamental, but is useful for planting
Botanical Gazette, v. 91.
222
BULLETIN 68.
7. Populus laurifolia (or P.
Certinensis). Slow-grow-
ing shoot. ( 2 /T, nat. size. )
where wind-
breaks are de-
sired quickly.
Like the Car-
olina poplar,
it has a strong
upright habit
of growth."
5. Popu-
lus laurifo-
lia (lyedebour
Icones Planta-
rum Nov.
Ross. v. 23, t.
479 (1834).
P. balsami-
f era, \&r. laur-
ifolia, Wes-
mael, D. C.
Prodr. xvi. part ii.
330. P. Certinensis, P.
Petrovski and P. Bereolensis
of American horticulturists).
CERTINENSIS POPLAR, Figs. 7, 8 ; j.
fig. i. This Siberian species is the most
important of the recently introduced
poplars. It is a very rapid-growing and
hardy tree, with a strong central leader,
and a very heavy dense foliage. It is
the Old World representative of our
cotton wood. The foliage upon the old
wood or upon slow-growing shoots (Fig.
7) is very unlike that upon the vigorous
branches, and it is almost identical with
that of the balsam poplar, being broadly
oval, with finely serrate margins, and
whitish beneath. The twigs, also, are
cylindrical. But the strong shoots are
THE CULTIVATED POPLARS. 223
strongly angled or grooved and the foliage is much like that of
the native cottonwood but darker ; and the growth is more close
and erect. The sketch in Fig. 8 distinguishes the leaves perfectly,
however :
P. laurifolia or Certinensis P. monilifera or Cottonwood
(upper leaf). Leaves broad-ovate (lower leaf). Leaves triangu-
in outline, with a rounded or lar-ovate in outline, with a
tapering base and rather short straight or truncate base and a
point at the apex ; the margin long point at the apex ; margin
rather closely toothed, wavy ; coarsely scallop-toothed, plane;
leaf-stalk comparatively short, leaf-stalk long, much flattened
only moderately flattened, gland- beneath the blade of the leaf,
less at the top ; stipules present and commonly bearing two or
and conspicuous. Bud long, three gland-like bodies at its
Shoots slightly hairy. top; stipules absent or minute
(falling early). Bud shorter.
Shoots glabrous.
I imagine that the similarity of the Certinensis poplar and cot-
tonwood has been the means of confusing them, for I have pop-
lars under the names of P. laurifolia and Riga No. 40, which are
cottonwoods. Whether these were really introduced from Russia
after having first been introduced there from America, or whether
the confusion is a mixing in our own plantations, I am unable to
say. The Certinensis poplar is a more rugged tree than the cot-
tonwood, with healthier foliage in the presence of leaf-rust, and
its wood is said to be valuable. It is now much planted in the
Northwest, and deserves to be more widely distributed.
Its effect in the landscape is considerably unlike that of the
cottonwood. Its leaves out stand more horizontally, while those of
the cottonwood hang loosely and often vertically and therefore
give the tree top a heavier look. The terminal spray of the two
is particularly distinguishable in this regard. The leaves of Cer-
tinensis upon the strong erect shoots stand almost squarely at
right angles with the shoot, and, at some distance, therefore pre-
sent only their ruffled edges to the eye, producing a most unique
and picturesque effect. But on the whole, at least for the present,
I should consider the cottonwood the better tree for ornamental
planting in this state.
22 4
68.
Professor Craig, of Ottawa, writes of the species : "I have
been sending out cuttings of these so-called Russian poplars to
Manitoba and the Northwest Territories for the past four years.
The species
which has given
best satisfaction
so far is one called
Populus Certi-
nensis. It resists
drouth and cold
remarkably well,
and is looked
upon by the
settlers of the
Northwest Ter-
ritories as one of
their most valu-
able shelter and
timber trees.' '
The Certinen-
sis poplar was
used in the la-
goon plantations
at the World's Fair, but because of its rapid growth in the direction
of its leader, it made a less picturesque small tree than either the
cotton wood or balm of gilead, which were similarly planted.
8. Certinensis poplar (above) , and Cottonwood (below}.
z nal. size.
THE CULTIVATED POPLARS.
225
The name laurifolia, or "laurel-leaved," is generally applied in
this country to another plant, Populus balsamifera, var. inter-
media. The name originated with the Russian botanist L,edebour,
and he published a good illustration of the tree he had in mind
and it is an admirable portrait of the large and crinkly leaves of
the tree which in this country goes under the name of Populus
Certinensis, a name which, so far as I can learn, is simply a
garden or nursery name. No. 39 Riga, as I have it, is the same.
Neither am I able to distinguish
the tree grown in this country
as Populus Bereolensis. Koch*
mentions a Populus hybrida
Berolinensis as being a hybrid
between P. balsamifera and the
Italian poplar (or Lombardy),
but his tree is probably not
the same as the one grown in
this country.
6. Populus monilifera
(Aiton, Hort. Kew. iii. 406
(1789). P. angulata, Aiton,
Hort. Kew. iii. 407. P. Caro-
Imensis, Moench,
Verzeichniss
Weissenstein, 81
(1785 : Catalogue
name). P.glandu-
losa, Moench, Meth-
odus, 339 (1794)-
P. Canadensis,
Michx. f. Hist.
Arb. Am. iii. 302,
t. 12. P. Carolina
of nurserymen). 9 ' p P ulusmonili f era ^ unu ^^ l form. (% nat.size.}
COTTONWOOD, CAROLINA and CANADIAN POPLAR. Fig. 8, 9; i,
fig. i . A strong growing handsome tree of large size, ranging from
Dendrologie. ii. iA, 497.
226 BULLETIN 68
western New England to Florida and the Rocky Mountains. Its
leaf characters are sufficiently outlined above (under P. laurifolia) ,
but it is variable in shape and color of leaves. Some of the forms
are fairly distinct in foliage and aspect, and they appear to be
associated with particular horticultural names, in the nurseries.
Fig. 9 shows a form with very long-pointed and round-based leaves;
but it usually bears, also, the typical triangular foliage. Some of
the most ornamental specimens of cottonwood are those which have
reddish leaf-stalks and midribs.
Taking all things into consideration, the cottonwood is prob-
ably the best of the poplars for general ornamental planting. It
grows rapidly and in almost every soil, and yet it possesses an air
of strength and durability which most of the poplars lack. Its
foliage is always bright and glossy, and the constant movement of
the broad rich green leaves gives it an air of cheeriness which few
trees possess. The tree has been much used upon the western
prairies and in western towns, much too abundantly for good
landscape effects. The rapid growth of the tree gives a feeling of
luxuriance to plantations, even when most other trees appear to
be weak or starved. The cottonwood thrives best upon rather
low lands, and yet it is generally an admirable tree upon high and
dry areas.
The so-called Carolina poplar is only a very luxuriant cultivated
form of the cottonwood. As sold by the New York nurserymen
it does not differ otherwise from the wild Popuhis monilifera of
our woods and creek borders.
There is a golden-leaved form of the cottonwood known as var-
iety Van Geertii or var. aurea. It is one of the best of yellow-
leaved trees, and generally holds its color throughout the season.
Like all trees of this unusual character, it should be used
cautiously, and the best effects are obtained when it is planted
against a group of trees so as to appear as if naturally projecting
from the other foliage.
7. Populus nigra (Linn. Sp. PI. 1034 (i753). P. Hudsonica,
Michx. f. Hist. Arb. Amer. iii. t. 10. P. beiulifolia, Pursh, Fl.
Amer. Sept. ii. 619. P. Eugenie of nurserymen). BLACK POP-
LAR, h and 1, fig. i . A European tree of medium to large size,
with leaves somewhat resembling those of the cottonwood, but
THK CULTIVATED POPLARS. 227
generally smaller and much less deeply toothed, shorter in propor-
tion to their width and often with a tapering or rounded base.
The tree usually has a pyramidal habit of growth and a dark cast
to the foliage. The leaf-stalk is flattened, so that the foliage
moves freely in the wind. It is a less lustrous tree than the cot-
tonwood and grows more slowly. Specimens were found escaped
along the Hudson by Michaux, who thought it an American
species and published it early in the century as Populus Hudsonica.
Pursh in 1814 published it again as the " birch-leaved poplar, "
Populus betulifolia , from trees found upon Lake Ontario. Although
is was found half wild in New York about a century ago, it does
not seem to have increased itself in America, for it is rarely seen,
even in cultivated ground. The tree known in the West as Pop-
ulus betulifolia is only a robust form of the European P. nigra.
The black poplar runs into many perplexing forms. The best
which I know is var. elegans {Populus elegans of nurserymen,
f, fig. i). It is a tree of pronounced strict or pyramidal habit,
but considerably broader than the Lombardy. The foliage is
small and light colored and very versatile in a breeze, with a
handsome reddish tint to the leaf-stalks and young shoots. It is
worth growing in every well kept place, especially if placed
against a planting of heavier foliage. Popidus canescens of some
American nurserymen is very like this, although it has less color
and brightness.
P. nigra, var. Italica (Du Roi, Harbkesche Baumz. ii. 141
(1772). Var. pyramidalis, Spach, Ann. Sci. Nat. 2nd ser. xv. 31
(1841). P. Italica, Moench, Verzeichness Weissenstein, 79 (1785).
P. dilatata, Aiton, Hort. Kew. iii. 406 (1789). P.fastigiata, Desf.
Hist. Arb. ii. 265 (1809). P. pyramidalis, Rozier, Diet. d'Agric.
vii. 619. P. pyramidata, P. Pannonica, P. Polonica of horticul-
turists). LOMBARDY or ITALIAN POPLAR. This tree is too
familiar to need description. It differs from the typical black
poplar (P. nigra} in its tall narrow growth, glabrous young
shoots, a confirmed habit of suckering from the root and generally
a more tapering base to the leaves. It is one of the characteristic
trees of parts of Italy, and it is from one of the Italian provinces,
Lombardy, that its common name is derived. The tree is prob-
ably native in Asia, however.
228
BULLETIN 68.
The L/ombardy poplar was much prized in this country a hun-
dred years ago. John Kenrick established a commercial nursery
of ornamental trees in Newton, Massachussetts, in 1797, and two
acres were ' ' devoted to the cultivation of the L,ombary poplar,
which was about the only ornamental tree for which there was
any demand in those days."* It is probable that very few, if
any, of the trees sold by Kenrick are still living, even in locali-
ties where the climate is not
severe ; and this is evidence
that the tree is short lived a
fact which all careful observers
must have noticed.
A hardy type of the Lom-
bardy is grown in the North-
west. Professor Budd gives
the following account of it.f
''In the summer of 1882
Mr. Gibb and the writer were
surprised to find the Lombard y
poplar in perfect health in
central Russia, where our
locust, hon-
other trees
killed down each winter as
does the common peach in
north Iowa. Our surprise came from the fact that L,oudon in-
clined to the belief that Populus dilatata [one name for the L,om-
bardy Poplar] was native to the valley of the Po in L,ombardy,
from whence it came to England and America. But Russian bot-
anists soon assured us that its home was in the east and that its
hardiness varied like other species, and hence depended on the
region from whence it was obtained. Under the name of Populus
dilatata we imported the hardy kind from Voronesh, in central
Russia. As this is 300 miles north of the sea of Azoff, from
whence came the Russian Mennonites of Minnesota, I suspect
*Garden and Forest, i. 302:
fRural Life, Aug. 31, 1893, p. 12.
10. Lombardy Pop-
lar. (% nat. size.}
American black
ey locust and
THE CULTIVATED POPLARS. 229
that our importation is hardier than the one seen around St. Paul.
We call it the Russian Lombardy. It is a much nobler tree than
the variety from the Po valley, as its top is not so thin and spiry,
and its foliage is thicker and darker. We have not talked about
this poplar for the reason that its timber has no relative value.
Yet it fills a place in landscape gardening not taken by any other
tree."
The various merits of the Lombardy poplar which is the most
familiar tree of the genus have been already discussed. It has
been planted too freely, but it is gradually dying out in the east,
and time will no doubt eliminate its offensiveness in the landscape.
There is said to be a form of the Lombardy with variegated leaves,
but I hope that it will not find its way into this country. A tree
which is already over-bold would be impertinent with a painted
foliage. " Planted as it was a hundred, or even fifty years ago,
in all possible situations, without regard to its surroundings or to
the positions in which it was placed, it did more, perhaps," says
Garden and Forest, ' than any tree which has ever been planted,
especially in some parts of Europe, to disfigure the landscape.
There is no tree, however, which can take its place, or which can
so quickly send up a tall, slender shaft to break a low or monot-
onous sky line. It became an unpleasant feature in the landscape
only when it was used without judgment and without discretion."
GROUP II. ASPENS and WHITE POPLARS, with short non-glu-
tinous often pubescent buds.
8. Populus Tremula (lyinnaeus, Sp. PI. 1034). EUROPEAN
ASPEN. Figs, n, 13. An open-headed, light-leaved tree,
common throughout Europe, and occasionally cultivated in this
country, especially in its weeping form. Leaves small and thin
round-oval, more or less whitened beneath, especially when
young, bordered with deep and rounded incurved teeth. Leaf
buds small. The leaf-stalks are long and slender and flattened,
giving a restless motion to the foliage.
The weeping form of the European aspen is perhaps the best
weeping tree amongst the poplars. The spray is light, airy, and
fountain-like, quite unlike the more common weeping forms of
our native Populus grandidentata, which present a stiff weeping
aspect, a combination which is rarely pleasing. The lightness
230
BULLETIN 68.
of the foliage
of the Euro-
pean aspen
has been re-
tti arked by