58 
THE GARDENERS' CHRONICLE OF AMERICA 
w^ 
GETTING SHRUBS INTO SHAPE. 
TJl the Ixginning ot the }car those having the 
eare of shrubs will rind occupation in their 
pruning. The main principle of shrub pruning has 
been too often explained to need much repetition now. 
Briefly it is to prune but little, shrubs that flower in 
Spring, and severel}' those known as late Summer or 
Fall flowering. 
It is presumed, writes Joseph .Meehan in Florists' 
t.vc/uin^i^c, everyone knows or can easily ascertain the 
season the shrub before him blooms, so that just how 
to proceed in the use of the knife is not difficult. 
In a general wa}-, those that are Spring blooming 
are supposed to go untouched after their growth is 
made in Summer, but the writer has found it to ad- 
vantage to look them over again in Winter or in ad- 
vance of S])ring. There are often awkward-looking 
branches which would be better removed, as well as 
some old growth, the removal of which would add to 
the neat appearance of the bushes. Besides this, one 
may often put a better shape to them by cutting back 
some of the past season's wood, but not all of it. There 
are always shoots of some length, of this latest 
growth, so that, even when these are partly cut back, 
there still remains some of the flowering wood un- 
touched, and often the result is that the flowers that 
do come later are better and finer than they would 
have been had the branches been impruned. ^\'hile 
well recognizing the importance of keeping in mind 
the different ]3nming required by the two classes of 
shrubs, the writer by no means thinks that the Spring 
blooming sorts should go untouched in Winter. _^ 
The partial priming in Winter gives to the florist 
and the nurseryman the opportunity to procure cut- 
tings for propagation, an important matter with many 
of them. Those who rely largely' on such propaga- 
tion provide for a supply Ijy having a portion of their 
grounds set apart on purpose to grow shrubs for cut- 
tings. These shrubs are, of course, treated in the way 
of priming to give the greatest number of shoots for 
cuttings, irrespective of flowers. The harder they are 
pruned back in Winter, the more and stronger will be 
the shoots that are made the Summer following. 
The principles of pruning are now much better 
known than they were in the past ; still one may see 
now and again shrubs on small lawns totally ruined 
for flowering, where incompetent men have been sent 
to prune them. 
THE MINERAL FOOD OF PLANTS. 
C O far as our present knowledge goes, the food re- 
quirements of plants are surprisingly modest. 
Besides water and carbon-dioxide all they e.xact from 
the soil are compounds of nitrogen, phosphorus, sul- 
phur, potassium, lime, magnesium, and iron. Hence 
it is not surprising that physiologists should from time 
to time ask the question. Do these elements satisfy all 
the complex requirements of plants or are other ele- 
ments, albeit in minute quantities, also necessary? The 
question is easier stated than solved, for there are many 
and formidable experimental difficulties to be overcome 
before a sure answer may be obtained. It is obviously 
impossible to seek an answer from the behavior of 
plants growing in soil, for it is a well-established fact 
that just as jackdaws acquire and secrete in their nests 
any unconsidered trifles which come their way, so 
plants may absorb in considerable variety and quantity 
many, if not all, of the mineral elements which occur 
in the soil. They may even to their detriment absorb 
poisonous substances. Wherefore it follows that the 
occurrence of this or that element in a plant is no index 
of its usefulness or indispensableness to the plant. Di- 
rect experimental investigation of the problem is difii- 
cult owing to the facts that, on the one hand, ordinary 
chemicals are by no means absolutely pure, and glass 
or earthenware in which plants are grown contains 
many dift'erent substances, traces of which may pass 
into solution, and, on the other hand, a substance may 
be essential to growth even though the minutest traces 
of it are required. 
Therefore in order to carry out an experiment the 
utmost care must be taken to emplo}' chemicals of ab- 
solute purity and to see that the plant used in the 
experiment does not serve, by way of the reserve food 
of its seed, to supply a sufficiency of these doubtful 
elements to the germinating seedling and to ensure 
that no substances derived from the glass receptacles 
in which the plants are grown or from particles of 
dust find their way into the plant. 
The most recent experiments which have been made 
ha\e been carried out by M. Maze* with all possible 
[irecautions. They appear to show that with the maize 
plant the above enumerated indispensable elements da 
not e.xhaust the list, but that to them must be added 
manganese, zinc, silicon, and cerium. It may be noted 
that the importance of manganese has long been sus- 
pected, that zinc is known to play curious tricks in the 
speeding up of growth, and that silicon, according to 
some experiments, though not according to others, is 
essential for the growth of cereals. Furthermore, al- 
though the maize plants developed and set seed when 
all the elements of the two lists given above were pres- 
ent, this was only the case when spring water was 
used. W^hen spring water was replaced by distilled 
water purified by repeated redistillation even this 
lengthy series of elements did not suffice for complete 
development. The failure of the crop was traced to 
the absence from the distilled w-ater of compounds of 
boron, aluminum, fluorine and iodine, traces of which 
were found to occur in the spring water. 
Whether these remarkable conclusions apply to other 
plants or whether they are peculiar to maize is not 
known. On general grounds we may be fairly sure 
that if the conclusions hold good for maize they will 
also be found to apply to other plants as well. 
Nor should anyone hastily conclude that facts such 
as these are of academic interest only. They may well 
prove to be of economic value as well. For example, 
the presence or' _absence of traces of one or other of 
these supernumerary elements may exercise, for all 
we know to the contrary, a decisive influence" on the 
immunity from or susceptibility to disease. It is- 
therefore to be hoped that the all-important question of 
the complete dietary of the plant shall be established 
on an indisputable experimental basis. — Gardeners' 
Chronicle (English). 
•Comptes Pendus, 1915, 160, 211. 
Of Interest to Estate Owners 
The National Association of Gardeners maintains a Service Bureau 
n-hich Is at the disposal of all who may require the serrices of efficient 
gardeners In their various capacities. 
The association seelis the co-operation of estate owners in its efforts 
to secure opportunities for those engaged In the profession of garden- 
ing who are seeking to advance themselves. It malces no rtiarpe for 
services rendered. It endeavors to supply men qualified to asRiime the 
responsibilities the position may call for. 
Malie your requirements iinown to 
M. C. EBEL, Sec'y, National Association of Gardeners, Madison, N. J. 
