la pépinière de Dropmore Manitoba

[palustris]

J'ai trouvéce texte a propos d'un esaie de rusticité de plusieurs espèces dans le nord du Manitoba le texte date d'il y a quelques année mais il y a beaucoup d'information pertinentes a propos de la rusticité de plusieurs arbres et arbustes désolé mais je n'ai pas traduit.
ARNOLDIA .
A continuation of the ’
BULLETIN OF POPULAR INFORMATION .
of the Arnold Arboretum, Harvard University
VOLUME 7 JUNE 27, 194 % NUMBER 6
FIFTY YEARS OF GARDENING IN NORTHERN MANITOBA
I was always fond of gardening. I probably inherited this love of plants, for
among my mother’s people there was usually at least one in each family who
was fond of growing things. One of my ancestors planted a garden over two
hundred years ago that is still one of the show places of Scotland.
Some of the happiest days of my early childhood were spent in an old garden
near Aberdeen, Scotland. It was there I really learned to know many plants that
are still my favourites. Among the shrubs were rhododendrons, lilacs and mockoranges
; there were fragrant herbs such as myrrh, rosemary and southernwood,
and the path that led down to a bed of old-fashioned moss and cabbage roses was
bordered with double white and pink varieties of Dianthus plumarius. The vcindow
of my bedroom looked out into an old Yew tree, covered in the fall with red
berries, and the birds that sheltered there would wake me up m the morning
with their song. Along the edge of the driveway :1’arcissus poeticus and daffodils
were naturalized under the maples that formed the avenue. A small stream, or
"burn" as we call ~t in Scotland, ran through the property and Minaulns luteus~
grew m the grass along its banks, apparently wild. Dow n by the wall under
which the burn flowed there was a copper beech, a few of whose branchlets trailed
m the water as if loath to see it go. It was here, also, that I first knew the
monkey puzzle tree, a tree that can be grown in Boston, only under glass.
I am the youngest of a large family which came to Canada fifty years ago and
settled near where I now live in northern Manitoba. At that time this was the
northern outpost of agriculture in Manitoba. V~’e were thirty miles from the nearest
town which had only one train a week. There were no telephones or motor
cars in those days and the journey to town and back took two days with horses.
The early settlers made their living principally by stock-raising and little gardening
was done other than the growing of enough of the more common vegetables
for home consumption. At that time there were no varieties of either corn or 30
tomatoes that could be ripened out-of-doors in northern Manitoba. A few zinnias,
petunias and portulacas were sometimes grown, but I was told that it was scarcely
worth while bothering with them as they would only be coming nicely into bloom
when the early autumn frosts would destroy them. In spite of this, the first dollar
I had was saved for the purchase of flower seeds and I was able to show those
early settlers that other flowers besides petunias, portulacas and zinnias could be
grown in this district.
There was no horticultural page in any of the Manitoba papers those days, and
the only horticultural information within my reach was contained in the annual
reports of the Dominion Government Experimental Farms which were established
~n 1886. In these reports I found a mine of information including articles on plant
breeding by the late Dr. William Saunders, the founder and first director of the
Dominion Experimental Farms. As I grew to manhood I started growing trees
and shrubs from seed secured from trade sources and also from the horticultural
division of the Experimental Farm. Later on, when I secured a farm of my own,
I bought nursery stock from many available sources, only to find that very few
of my old favourites could be cultivated here. None of the old roses were fully
hardy, neither the mockoranges nor Spiraea Van Houttei could be expected to
flower unless protected, and even the common lilacs were sometimes injured by
our severe winters. At that time it was thought that trees also, especially conifers,
could not be grown on the Canadian prairies. The reports on Dr. Saunder’s
work in plant breeding led me to think that possibly I, too, could obtain or produce
new strains that would be hardy here.
The quest for material to carry on this work led me into correspondence with
many men and institutions well known to the horticultural world, including the
late Professor C. S. Sargent; Mr. W. T. Dlacoun, Dominion Horticulturist; and
the Edinburgh, Kew, and Upsala Botanic Gardens. To all these men and institutions
with which I came in contact, either personally or by correspondence, I
owe much. My horticultural work at this time was merely a hobby, as in conjunction
with a brother I was carrying on a fairly large grain and stock farm and
I was in charge of the live stock end of the business. Being much in the saddle
I had a good opportunity to get acquainted with our native plants and to study
their habits.
As my collection of plants grew, I found that there was quite a difference in
the hardiness of geographical forms of the same species. For instance, the Scotch
pine, usually grown from commercial seed collected in Germany, was hardy in
ordinary winters, but every so often we would have test winters that would kill
many of them outright and badly injure many more. The same species when
grown from seed of the north-Russian, Finnish, or north-Swedish forms is equally
as hardy as our native Jack pine and a very much finer and faster growing tree.
With the Norway spruce, the Finnish form is also much hardier than that grown
from ordinary commercial seed, and can stand our worst winters without injury.
PLATE V
Tilia cordata
32
An interesting example of this variation of hardiness within the species is provided
by Acer glabrum. I have collected this maple from four different sources,
viz. near Boulder, Colorado; west of Cheyenne, Wyoming; at Waterton Park in
southwest Alberta ; and just west of Fernie in southeastern British Columbia. Our
Canadian forms usually kill to near the snow line; some of those from Wyoming
have suffered in very severe winters, but the lone specimen from Colorado has
never been injured by winter.
Ulmus pumila has given us a very vivid illustration of the difference in hardiness
of geographical strains. In 1940 a nursery row 100 yards long had three
quarters of its length planted to this elm grown from seed secured from Harbin,
Manchuria, and the balance of the row was planted to a strain that had been
hardy for a number of years in southern Manitoba and was bearing seed there.
In September 194z, the temperature went down to zero, and during the following
winter we had temperatures of -50 and -550 F. In the spring of 1943 the
Ulmus pumila from Harbin was alive to the tips of the branches, while the other
strain was killed out, root and branch.
With many other trees and shrubs I have found that the forms in commerce
are not suited to our conditions, and were hardy only when special strains were
collected or secured from correspondents. Besides the examples already noted,
the following are hardy at Dropmore only when special strains are secured :
Acer saccharinum
Deutzia parviflora
Juniperus communis
’
Juniperus scopulorum
Juniperus virginiana
Larix decidua
Larix leptolepis
Larix occidentalis
Pinus contorta
Pinus flexilis
Pinus strobus
Prunus triflora koreana
Pyrus ussuriensis
Tilia americana
’
Tilia cordata
Thuja occidentalis
Ulmus japonica
Ulmus scabra
Weigela florida
The hardy strain of Ulmus scabra came to me as seeds from the Upsala Botanic
Gardens, and Ulmusjaponica is the Manchurian form sent to me by the Bureau
of Plant Industry at Washington. Prunus triflora koreana is even hardier than the
wild Prunus nigra that I collected twenty miles east of Dropmore. The fruits of
some of its varieties are excellent eating, raw or cooked, and come nearer to
the domestic varieties in quality than any other plum that is hardy here. I have
crossed this plum with our sand cherries, sand cherry hybrids, and with a green
gage plum of my own raising. The latter cross gave weak plants that do not look
promising at the present time.
In October 1918, after four strenuous war years, I took a three weeks’ holiday
33
and paid my first visit to the Central Experimental Farm at Ottawa, and the
Arnold Arboretum. After having seen a little of the great wealth of material to
be found at the Arboretum, I decided to report to Professor Sargent. A kindlylooking
elderly gentleman, accompanied by a younger man, was pointing out
some trees as I approached and enquired the way to the Administration Building.
They were Professor Sargent and his companion, the Superintendent, while the
trees they were examining were Chinese pear species. I noticed that one tree
had already shed its leaves, and remarked to Professor Sargent that if any tree
was to prove hardy with us I felt sure that would be the one. It proved to be
Pyru.v uasurieu.ri.r and from the scion that I brought back with me I grew what is
now the oldest hardy pear tree on the prairies of western Canada.
Among the other treasures I brought back with me, were some one-year-old
seedlings of two lilacs grown from seed collected on the Diamond mountains of
Korea by E. H. V~·ilson in 1917. These lilacs (~yringa uelutiua and S. obkrta dilatnta)
have proved absolutely hardy at Dropmore ; and, therefore, in 1921 I crossed
some of the "French" lilacs, which sometimes are quite severely injured by our
winters, with S. oblata dilatala. A new race of "American’’ lilacs resulted which
seems better suited to our continental climate than the European varieties of the
common lilac. These new lilacs have several interesting features. Many of them
have bronze leaves in spring, and turn a deep purple m autumn. They do not
sucker to the same extent as do the older hlacs (in fact a hedge of the first hybrids
raised in 1922 has not suckered yet) and they are extremely free-flowering
and fragrant. In some of my later crosses of these lilacs the blooms compare well
with Lemoine’s varieties and are much hardier here in northern Manitoba.
Professor Sargent sent me seeds of several varieties of trees and shrubs collected
by Dr. J. F. Rock in western Kansu, but very little of this material has proved sufficiently
hardy for our cold, dry climate. At the present time, those that are still
alive and promising are Betula rclbo-sinen.si.s, Picea purpurea, Daphne Giraldii, D.
languticu, Potenhlla frufioosu and Cnrcrgaua brevifolia. I corresponded with Professor
Sargent until the time of his death-indeed, his last letter was written to me
just a few days before he died and it fell to me to write a Canadian appreciation
of his work.
In 192~, the Great Plains Horticultural Section of the American Association
for the Advancement of Science, met in Manitoba and about twenty of the members
spent a day at my place. Among this company were Professor Alderman of
the Division of Horticulture at the University of Minnesota and Mr. :41. B. Davis
of Ottawa (now the Dominion Horticulturist). They were quite surprised at the
variety of material I had succeeded in collecting and growing and also at the
amount of plant breeding I had already done These men strongly advised me to
keep on with the work, even if it meant commercializing it. By 19 2 rural western
Canada was already suffering from the post-war depression. I decided to take
the advice of Professor Alderman and Mr. Davis, and a few years later the Mani34
toba Hardy Plant Nursery was established and now has patrons from the Yukon
to Europe, and as far south as New Zealand.
Next to growing the plants themselves, I enjoy reading books on plants and
their distribution. As we are so far from any large town, I have no opportunity
to consult the horticultural or botanical shelves of a good library, so have had to
build up a small library of my own. In one of my books, "F’lore des Serres et
des Jardines de I’Europe," Vol. XIX, I saw photographs of Cnrttgann jxbata and
Malus bwcatrr ",flore roseo pleuo" and decided that both probably would be hardy
if I could secure them. After several years I obtained the Caragana and now haB e
a well-grown bush of it about four feet high. The young branches of Caragana
,jubata are very wooly and the leaf stalks and strpules become hard and thorny,
making it a difficult shrub to graft. Under conditions in this hemisphere it is also
difficult to raise from seed, and is therefore likely to remain scarce in American
gardens. I consider this a pity, as it is rather striking looking when in bloom.
The double-flowered Malus baccata has so far eluded me and apparently is no
longer grown in western Europe.
Another of my own books, Bean’s "·I’rees and Shrubs Hardy in the British
Isles," indicates that a number of hardy trees and shrubs from cold dry sections
of the northern hemisphere do not flourish in Britain. Bean speaks of one of these
as follows: "Populus lrislis (Fischer~ is a balsam poplar allied to the above, wrth
similar downy shoots and leaf stalks .... Brandis, alluding to it as P. balsamjfern,
says it occurs in arid valleys of the inner north-western Himalayas. Probably
our climate is too moist and dull for it. Although introduced in 1896 from
Spaeth’s Nursery at Berlin, it has never succeeded ; and although it makes vigorous
growths during the summer, they are frequently cut back in winter, and it
has never got beyond a few feet high. " Ten years ago I obtained cuttings of this
poplar from Kew and now have several trees over thirty feet high. Besides being
a fast grower, and very easily propagated from cuttings, it is highly resistant to
the leaf rust that frequently disfigures all our native poplars. So far I have hybrids
between it and our aspen and balsam poplar, and have seeds ripening on
cottonwood that were fertilized with its pollen. I hope to get a disease resistant
tree with soft white wood that will grow easily from cuttings.
The way that some plants appear in gardens often makes a most interesting
story. Ribes tliacnnthurn unexpectedly grew in my garden from some unknown
source years before I securecl seed of it from a correspondent in Manchuria. This,
by the way, is a much more attractive shrub in northern Manitoba than R. alpitrrtm.
It grows up to four feet high and besides fruiting freely its foliage colours
up brilliantly in autumn. I,crri.v Gmelitri juporrica came to me from the Yokohama
Nursery Company under the name of Larix leptolepis. Knowing that it was not
named correctly, I sent a sample of the seed to the late E. H. Wilson, who found
out from the manager of the Japanese firm that the seed had been collected in
the Kurile Islands. This larch is better suited to our climate than L. leptolepis and
my plants look as if they will develop into beautiful specimens. In the midst of
a block of Siberian spruce, some of which have now started to bear cones, there
is one answering the description of Picea bicolor reflexa. This seed was secured
from Johannes Rafn & Son of Copenhagen, Denmark, and it is just possible that
a few of the seeds of the Japanese spruce may have become mixed with the Siberian
species. Seeds of juniper from Japan yielded one plant that was quite
obviously different from the rest. Now over fifteen years old, this has quite an
ancient tree look about it, though only twelve inches high and about sixteen
inches across. So far it has pro~ ed quite hardy with us. A rooted cutting is now
in the nursery of the Arnold Arboretum under the provisional name of Chamaecyparis
"Dropmore variety." It has not as yet borne fruit.
Two shrub families that are interesting garden subjects and have quite a few
members that are hardy in northern Manitoba are the daphnes and the brooms.
Besides the two daphnes already mentioned we have Daphne Me~ereum, B. Cneorum
and its lovely and very dwarf white form, and a six-inch plant of D. collina
which came safely through last winter without protection and has flower buds
now showma colour. Among the brooms, Cytisus decumbens becomes a mat of y-ellow,
two inches high and one to two feet acoss in June. Cytisus nigricans, C.
rrustriacus, C. elongatxs, C. hirsutres, C. leucanthus var. Schipkaensis, and C. pxzrpureus
all have forms sufficiently hardy to be worth cultivating. In genistas, the spinyfour-
to-six-inch bushlets of Genista sylvestris flower freely. Genista tinctoria and
the double-flowered form are very showy and reliable. Genista sngittalis, though
~t at times suffers a little from our winters, is as a rule a mass of gold in summer.
Another member of the pea family that is quite hardy here is Maackia nmurPnsis
with its upright spikes of yellow-eyed white flowers. In some seasons this seed
ripens freely with us.
Before the great drought of the nineteen thirties completely wiped out my collection
of rhododendrons, I had some measure of success with a number of the
hardiest species. Both Rlzodozlendron hirsutum and R. ferrugineum had flowered for
several years. Even R. caucasicum had lived through a winter and flowered. Seedlings
of its close relative, R, chrysanthum, proved winter-hardy and I had hoped
to raise hybrids between these two. Unfortunately, before R. clrrysantlzu~n flowered,
the drought period had reached us and in July it died. Our only water
supply at that time came from a well 285 feet deep and it contained far too much
lime and iron to be of any value to rhododendrons. Rhododendron mucronzzlatunr,
R. canadense, and Erica carnea have all lived long enough to flower when planted
in especially prepared soil, but curiously enough I have had little success with
R. dauricum. «’here suitable soil and moisture conditions can be prov ided, and
snow covering in winter can be relied upon, there is no doubt that a number of
rhododendrons would prove hardy and fairly easy to cultivate. In such a location
there is a wide open field for the plant breeder who cares to work with this type
of shrub.

Some of the More Unusual Trees at Dropmore
Acer saccharinum, 35 feet high, bole circumference °~2 inches.
Larix decidua, up to 50 feet high with bole circumference up to 2 feet 4 inches
at 30 years of age.
Larix Gmelini japonica, 25 feet high, with a bole circumference of 13 inches.
This is a most variable tree in leaf colour and habit, and some forms are highly
ornamental.
Larix laricina, up to 50 feet in height with bole circumference of 2 feet 4
inches. Though usually found growing in swamps in nature, this tree has stood
the drought years much better than any of the poplars.
Larix sibirica, thirty years old, up to 45 feet high with bole circumferences
running from 2 feet 4 inches to 3 feet at 3 feet above ground level. A belt of
seedlings eleven years old are now up to 25 feet in height, some of them with a
bole circumference of 23 inches at 3 feet above ground. The parent trees were
growing near the European and American larches and many of the young trees
show signs of hybrid origin in both the bark and cones.
Picea abies, a beautiful specimen in a sheltered spot, 45 feet high with branch
spread of 28 feet, bole circumference 3 feet.
Picea pungens glauca, 35 feet high, bole circumference 2 feet 10 inches.
Pinus Cembra, ?0 feet high, bole circumference 17 inches at 3 feet.
Pinus Cembra sibirica, 24 feet high, bole circumference 1 inches.
Pinus flexilis, 1 feet high, bole circumference 11 inches.
Pinus sylvestris, 30 years old, now up to 50 feet high with bole circumference
running from 2 feet 6 inches to 3 feet.
Populus tristis, ten years old, over 30 feet high with a bole in circumference
of 2 feet 8 inches and a branch spread of 22 feet.
Pyrus ussuriensis, twenty-six years old, circumference at three feet, 2 feet 1o0
inches, height 25 feet, spread of branches 25 feet.
Sorbus amurensis forms a clump reaching a height of 24 feet, the main stem
having a circumference of 25 inches, three feet from the ground.
Sorbus aucuparia grown from seed collected near the headwaters of the River
Tay in Perthshire, Scotland; now 20 feet high and with three main stems from
12 to 15 inches in circumference.
Thuja occidentalis, 25 feet high, bole circumference 29 inches at 2 feet.
Tilia americana, 30 feet high, 25 feet spread of branches and bole circumference
of 2 feet 8 inches at three feet.
Tilia cordata, a clump 2l feet high with a spread of 20 feet, the main stem
having a bole circumference of 23 inches.
Ulmus japonica from seed collected in Manchuria for the United States Department
of Agriculture. This tree has three main stems near the ground, each
of which is from 24 to 25 inches in circumference. Though only 20 feet high,
this tree has a spread of branches of 24 feet.
PLATE VII
Pyrus ussuriensis
39
Conifers at Dropmore
Abies balsamea
Abies holophylla
Abies nephrolepis
Abies sibirica
Chamaecyparis (?) Dropmore variety
Jumperus cmnmunis
Juniperus horizontalis
Juniperus Sabma
Juniperus scopulorum
Juniperus virginiana
Larix decidua
Larix Gmelini
Larix Gmelini japonica ,
Larix Gmelini japonica X sibirica
raised by intention at Dropmore
Lar~x Gmelini olgensis
Larix laricina
Larix leptolepis
Larix occidentalis
Picea abies
Picea bicolor reHexa
Picea Engelmanni
Picea glauca
Picea jezoensis
Picea mariana
Picea obovata
Picea purpurea
Pinus Banksiana
Pinus Cembra
Pinus Cembra sibirica
Pinus contorta
Pinus Hexihs
Pinus Mugo
Pinus ponderosa
Pinus resinosa
Pinus Strobus
Pinus syl~~estris
Pseudotsuga Douglasi~
Though much progress has been made in gardening during the past fifty years,
there is still much to do. Many of the trees and shrubs of northeastern Asia
with northern limits in Kamchatka, eastern Siberia, Saghalien and northern "
Korea, have been introduced to cultivation from their southern or insular limits
and may prove much hardier when secured from colder and drier districts. Syrirrga
jnponir·a, introduced to cultivation from Saporo in the north island of Japan
by Professor Sargent, is the only broad-leaved tree or shrub from Japan that has
proved fully hardy here. Possibly others from the same neighbourhood would repay
a thorough trial. While we have a small company of very enthusiastic plant
workers in western Canada who are doing much to improve our fruits, vegetables
and flowers by plant breeding, there is still much more to do than they can hope
to accomplish. Personally, I would like to see some of the following plants introduced
: a hardy weeping willow, a pyramidal poplar, a double-flowered Malus
baccata, large-flowered dogwoods, buckeyes with bright-coloured flowers (the Ohio
buckeye is quite hardy), and truly hardy viburnums with the fragrance and beauty
of Viburnum Cnrles~ii.
A complete list of hardy bulbs and herbaceous perennials that are grown at
Droprnore would be wearisome, so I will mention only a few of the more outstanding
that are finding their way into our northern gardens by way of Dropmore.
In early spring we have Callianthemum angust;f’olium with its pure white
buttercups, and Viola altnicn that becomes a mat of cream or yellow pansies
40
(rarely blue) in early May. These are hybridizing with the garden violas to give
what I hope will be a race of quite hardy pansies. Towards the end of June or
early July, Iris Kaempf’eri from Manchuria and Iris acutifolia, which came to me
from Leyden Botanic Gardens, are among the most striking flowers in the garden.
There is Ligularia speciosa with enormous elephant-ear leaves and fifteen to
eighteen-inch spikes of orange yellow flowers. Clcrysnuthemum Znumdskii from
Austria, though rather a disappointing daisy that is scarcely worth growing on
its own account, has given me some hybrids that are both hardy and beautiful.
(It is interesting to note here that the inspiration I got from a visit to Alex Cumming
of Bristol, Connecticut, started me breeding chrysanthemums.) Muscari
polyanthum is also quite at home and towards the end of May, Tulipa Oslrou·skiana
(scarlet) and T. Kolpakozeskinna (yellow) make brilliant patches of colour. In early
June the white narcissus of the Swiss Alps comes into bloom. This was collected
for me by Henry Correvon, high above Montreux, about twenty-five years ago,
and is the only narcissus that really does well here. Then as the German iris
starts to flower, we have Allium sebrlranense (pure white) and the blue laiolirion
montanum. These two make a lovely picture when grown together. Lilies of course
are grown by the acre at Dropmore, and our collection of these is being augmented
yearly. That, however, is a story in itself.
While my work with plants has been done entirely with a view to securing
forms suited for this region, it is interesting to note that some of my hybrids are
beginning to find a place in widely separated gardens of the world. It ~s a great
satisfaction to know that some of the new hybrids raised here have been sufficiently
outstanding to warrant their being planted elsewhere, even in gardens
where an extremely low temperature is not the all important factor in the selection
of varieties.
F. L. SKINNER
, Dropmore, Manitoba, Canada
Mr. Skinner owns and operates one of the most northcrn nurseries for ornamental
plant materials in North America. His experiences and observations in
growing ornamental woody plants where winter temperatures may go to -50° F.
or even lower may prove of interest to Arnoldia readers.