310 
THE GARDENERS' CHRONICLE OF AMERICA. 
erally considered necessary is for an incompetent work- 
man to give the shrubs an annual trimming with a pair 
of shears, with the result that when the work is fin- 
ished the shrubs all have about the same rounded, stiff 
appearance, much of the old growth which should have 
been removed is left and forms a mass of useless 
growth and the young wood, which should be care- 
fully preserved for future blossom, is cut away. It is 
not possible to lay down any hard and fast rule, as 
shrubs differ so much in their individual requirements, 
but it is better not to prune at all than to prune indis- 
criminately. The large majority of flowering shrubs 
produce their blossoms during the spring and summer 
months and some of these, such as the Philadelphus, 
Deutzias and Forsythias, which produce their flowers 
on wood of the previous season's growth, are im- 
proved by having some of the flowering stems cut clear 
out as soon as the blossoms have fallen. This will 
help to strengthen the new growths sent out from the 
base and give them a better opportunity of becoming 
well ripened before winter sets in. The majority of 
hardy shrubs, however, require very little pruning be- 
yond occasionally removing the old growth so as to 
keep them shapely and open to enable them to receive 
the full benefit of the sun and air. It is only by intelli- 
gent study and actual practice that one can become 
conversant with the requirements of different shrubs. 
As I have previously mentioned, it is quite unneces- 
sary when planting ornamental shrubbery to use only 
those shrubs which are of bushy form, and by the in- 
clusion of some of pyramidal growth for example, and 
the proper use of standards one can produce a very 
much more attractive arrangement. A very common 
mistake, which should be carefully guarded against, is 
to plant all the larger shrubs at the back and graduate 
the others down to the front. By bringing some of 
the larger shrubs to the front and placing a well- 
grown standard on the edge of the shrubbery, where it 
stands clear above its neighbors, one will be able to 
give the appearance of much greater depth, which is 
important where space is limited. It will, of course, be 
necessary when the shrubbery is first made to plant 
more shrubs than those which can permanently re- 
main. — Extracts from a lecture before the Massachusetts 
Horticultural Society. 
ESSENTIAL CHEMICAL ELEMENTS FOR 
PLANT GROWTH. 
A LL plants require at least ten of the chemical ele- 
"^ ments in order to develop properly. Most of 
these element; enter into the composition of the 
living material of the plant itself; the others are required 
to promote the chemical changes which are necessary to 
the growth and well-being of the plant. The complete 
absence of any one results in a cessation of normal 
growth ; a shortage of any one results in failure to obtain 
the fullest development. < >ne of them, the carbon, is 
obtained from the air ; the other nine are got from the 
soil. The yield of a crop depends largely upon the pres- 
ence of each of the nine in sufficient quantities in avail- 
able — that is, soluble — form in the soil. Of these nine, 
onlv three are likely to be deficient in most soils — the 
nitrogen, the potash and the phosphorus. There are usu- 
ally abundant stores of the remaining six. 
Each of the elements plays a certain definite part in 
the nutrition of the plant, and on account of this an ex- 
perienced person can generally tell whether any partic- 
ular element is deficient by an inspection of the growing 
crop. He has to take many things into consideration in 
forming his judgment, and he can, perhaps, form it 
most easily when a mixed lot of plants are growing upon 
the soil, for each of the three I have referred to encour- 
ages the development of a different set of plants. In the 
famous Kothamsted experiments, for instance, where 
potash and phosphates, but no nitrogen, were used in 
manuring pasture land, in course of time leguminous 
plants came to constitute half the herbage. Now, legu- 
minous crops have, by reason of the bacteria in the 
nodules on their roots, means of getting nitrogen which 
other plants lack, so that it is evident that the leafy 
grasses were discouraged by the comparative deficiency 
of nitrogen, and the idea is strengthened by the fact that 
the vegetation on the plots receiving only nitrogen, or 
nitrogen, potash and phosphates as well, consisted wholly 
of grasses. Deficiency of nitrogen results in stunted 
growth of shoot and foliage, a poor, starved appearance^ 
and yellowish tint generally. Conversely, excess of nitro- 
gen results in vigorous development of large, soft leaves, 
sappy shoots and a deep green lush appearance. 
Nitrogenous manures, then, are to be used when it is 
desired to encourage large leaf development and suc- 
culent growth. Too much will cause the plant to become 
so sappy as to be an easy prey to insect and fungus pests. 
The form to be used must depend partly upon the speed 
with which the results desired are wished for. Nitrate 
of soda and nitrate of lime are most active, as they are 
most readily available ; then follow sulphate of ammonia 
and calcium cyanamide, or nitrolim ; then the organic 
manures. The last vary in availability, mainly according 
to the rate at which they decay. 
Potash plays a different part. Without it the making 
of sugar or starch ceases ; exactly why is not known. It 
may be actually necessary for the formation of these 
things, or its absence may interfere with their movement 
from place to place. Plants with a deficient supply, 
therefore, soon grow slowly, and they usually have a 
poor color, while frequentlv the tips of the leaves die and 
turn brown. The epidermis does not appear to harden 
so much as when the supply of potash is sufficient, and 
tomatoes and the like are more liable to crack as a con- 
sequence. Deficient supplies of potash appear also to 
affect the coloring of fruits adversely. That their ripen- 
ing is affected is evident from the fact that sugar forma- 
tion is checked. Certain fungi are more easilv able to 
attack plants suffering from potash starvation. 
Potash manures are wanted particularly by plants 
which produce and store large quantities of sugar or 
starch. Beet, Carrot, Potato, Tomato, fruit trees and 
the like are all benefited by the application of potash salts 
where they are deficient. Clayey, strong soils often need 
liming to unlock the stores of potash they contain. The 
peculiar composition of these soils renders it quite pos- 
sible to reduce the amount of available potash by apply- 
ing soluble potash salts, paradoxical as it may seem, and 
lime is the best key with which to unlock the potash 
again. On lighter lands kainit in winter, or sulphate of 
potash or wood-ashes in spring, are an aid to crops. 
Phosphorus is best supplied as phosphates. Phos- 
phates have an extraordinary effect upon root develop- 
ment, and are thus a capital preparation for periods of 
drought. They hasten ripening, and they further the 
storing of food in seeds. They are, therefore, partic- 
ularly desirable wherever crops are wanted early, or 
where it is wished to encourage the ripening of wood, 
as with fruit trees and with tender shrubs in winter, and 
where crops are grown for their seeds. 
Superhosphate is best where lime is present in the soil, 
and may be used in spring, as may bone-meal. Where 
the soil is heavy or lime deficient, basic slag should be 
used. — Exchange. 
