1 
VOd 
PARK AND CEMETERY. 
THE BEST OF THE 
USEFUL HARDY SPIRAEAS 
An address at the annual convention of the Ontario Horticultural Association 
in Toronto, Nov. 16, by IV. T. Macoun, Dominion Horticulturist, Ottazua. 
It may be safely said, I think, that 
if the average person interested in 
plants were asked to name the best 
spiraeas he would immediately think 
of Spiraea Van Houttei among shrubs 
and the so-called Spiraea Japonica 
among herbaceous plants. We fear 
that with many persons their knowl- 
edge of spiraeas is limited to these 
two plants, and one of them is not 
a true spiraea, but belongs to the 
genus Astilbe. If this view is the 
correct one a paper on spiraeas 
should prove of value as introducing 
to lovers of flowers throughout Can- 
ada some of the many beautiful hardy 
species which can now be readily ob- 
tained. 
In a comparatively recent edition 
of the Guide to the Royal Gardens, 
Kew, there are recorded 63 species of 
woody or shrubby spiraeas, and 28 
r arieties or nearly one hundred dis- 
tinct sorts. Of the 63 species, 22 
are hybrids or of garden origin. Of 
the 41 which appear to be natural 
species, 10 are of American, 6 of 
European, and 25 of Asiatic origin. 
At the Central Experimental Farm 
there have been tested nearly 100 
shrubby species and varieties. As 
most of the spiraeas are natives of 
the north temperate zone and a large 
proportion of them natives of the 
colder parts of it, it is not surpris- 
ing that there should be many which 
are hardy or nearly so. 
The woody spiraeas may be divid- 
ed into two main groups, namely, 
those which bloom during the spring 
and those which bloom in the sum- 
mer. The spiraeas in the former 
group, so far as we are aware, all 
have white flowers, while those which 
bloom in summer are either white 
or pink or rose. Those which bloom 
in the spring are, as a whole, much 
more graceful and beautiful than 
those which bloom later on. The sum- 
mer flowering sorts have the advan- 
tage of having a long blooming sea- 
son, some of them flowering from 
June until autumn. 
While there is a very large num- 
ber of species and varieties it is not 
difficult to select the best dozen, and 
of these dozen Spiraea Van Houttei 
and Spiraea Arguta are the two best. 
DESCRIPTIONS. 
Spiraea Van Houttei is a hybrid 
species of garden origin, a cross be- 
tween Spiraea Cantoniensis and S. 
Trilobata. It is the latter species 
that gives to S. Van Houttei its hard- 
iness, as it is a native of North China 
and Siberia. One can scarcely say 
too much in praise of Spiraea Van 
Houttei. Its graceful form, attrac- 
tive foliage and wealth of white flow- 
ers are most striking, and it may be 
regarded as one of our most useful 
and beautiful shrubs. It blooms dur- 
ing the latter half of May, but while 
the bloom is over early in the season 
the new growth which takes place 
provides foliage which is attractive 
throughout the summer. It is very 
effective when massed close to the 
house. It grows from four to six 
feet high. 
Spiraea arguta is as hardy, or hard- 
ier, than Spiraea Van Houttei, and as 
it blooms early in May, before the 
latter is in bloom, there is no rivalry 
between them. This also is a hybrid 
species, being a cross between Spir- 
aea Thunbergii and Spiraea multi- 
flora (the latter of hybrid ori- 
gin), and is, like Spiraea Van Houttei, 
more beautiful than either of the par- 
ents and hardier than Spiraea Thun- 
bergii, which used to be the best 
known early blooming sort. Spiraea 
arguta is a graceful shrub, growing 
about four feet high and being liter- 
ally covered with small, white flowers 
on slender branches in the bloom- 
ing season. While the foliage is not 
quite so attractive as Spiraea Van 
Houttei, it is owing to its graceful 
habit quite ornamental after the 
blooming season is over. 
AN EARLY BLOOMER. 
Where it is hardy, the double var- 
iety of Spiraea prunifolia comes third, 
perhaps, in usefulness and beauty. It 
is one of the earliest to bloom, but 
it is too tender at Ottawa to make 
a good show, and is useful only in 
the warmest parts of Canada. The 
flowers are pure wliite, and are larg- 
er than most other spiraeas, and are 
quite double. This shrub continues 
attractive throughout the summer as 
the foliage is glossy and deep green 
in color. The autumn tints are also 
good. 
Spiraea Thunbergii is a very early 
bloomer, and one of the most grace- 
ful of the spiraeas, but is not hardy 
enough in the colder parts of Can- 
ada. Even where it is hardy it is not 
so desirable as Spiraea arguta, which 
blooms about the same time. Spiraea 
Thunbergii colors much more highly 
than Spiraea arguta in the autumn, 
and on this account is valuable for 
massing. It is a native of Japan, and 
grows three to five feet high. 
Of stiffer and more upright habit 
than any of the four preceding spi- 
raeas, but very showy because of its 
wealth of creamy-white flowers, is 
Spiraea Chamaedrifolia, a very hardy 
species, growing about six feet high. 
It is a native of Europe, reaching to 
Japan. 
Spirae ulmifolia is very similar, and 
Spiraea media is of somewhat the same 
habit. 
One of the most beautiful of the 
spiraeas is Spiraea Bracteata, often 
sold as Spiraea Rotundifolia Alba. 
The flowers of this variety are white 
and very conspicuous, in compact 
clusters and contrasting well with the 
rich green foliage. The species 
blooms early in June after Spiraea 
Van Houttei, which makes it par- 
ticularly valuable. It is not quite 
hardy enough at Ottawa. It is said 
to grow eight feet high, but where 
it kills back some, four feet 
would be a good average. This is a 
native of Japan. 
A spiraea which belongs to quite a 
distinct group from those already de- 
scribed, and which blooms from early 
summer for several weeks, is Spiraea 
Sorbifolia. This is now included by 
some botanists in another genus, and 
is known as Sorbaria Sorbifolia, get- 
ting its name from the leaves, which 
resemble very much those of the 
mountain ash. The leaves of this 
shrub are quite attractive, and when 
the strong stems bearing large 
panicles of flowers are thrown up it 
makes a most striking shrub. It 
suckers very freely, and on this ac- 
count should not be grown where it 
is liable to crowd less vigorous sorts. 
It is a native of Northern Asia, is 
very hardy and grows from three to 
five feet high. Of the same group is 
Spiraea Aitchisoni, a native of Af- 
ghanistan. It is an attractive shrub, 
but not hardy enough in the colder 
parts of Canada. 
There is a very distinct group of 
spiraeas which bloom during the sum- 
mer months, usually sold under the 
name of Spiraea Callosa and varieties. 
These are true Spiraea Japonica and 
varieties. They are low growing 
shrubs, from two to four feet high. 
The wood kills back very much each 
year, but they bloom freely on the 
new wood and are very showy dur- 
ing the summer months. Spiraea 
Japonica has a wide range in the 
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