THE NATIONAL NURSERYMAN 
the average percentage of nitrogen decreased appreciably 
after 1915, while that of potash decreased greatly after 
1914, and still more after 1916. The average percentage 
of available phosphoric acid increased considerably after 
1914, but with some variation from year to year. The 
total percentage of available plant-food decreased con¬ 
tinually after 1914. 
3. Effect upon cost. The average retail cost of one 
pound of plant-food increased year by year continuously 
after 1914 in the case of complete fertilizers, going from 
8.8 cents per pound in 1914 to 33.1 cents in 1919, an in¬ 
crease of nearly four fold. In the case of acid phosphate, 
nitrate of soda, bone, dried animal manures, etc., there 
was an increase in the retail cost of plant-food, but not 
relatively as great as in the case of complete mixed fer¬ 
tilizers. 
Retail Prices of Complete Fertilizers 
In Table IV we give for each year the average selling 
price of one ton of complete fertilizer, the number ol 
pounds of plant food per ton, the average cost of one 
pound of plant-food, and the relative cost based on the 
cost in 1914. 
TABLE IV. -COST OF PLANT-FOOD IN FERTILIZERS 
Year 
Average re¬ 
tail price 
per ton of 
fertilizer. 
Amounts of 
plant-food 
in one ton. 
Average re¬ 
tail price of 
one lb. of 
plant-food. 
Relative 
cost of one 
pound of 
plant-food. 
Pounds 
Cents 
1914 
.$28.53 
324.8 
8.8 
100 
1915 
30.87 
278.6 
11.1 
126 
1916 
35.00 - 
254.8 
13.7 
155 
1917 
34.40 
252.4 
13.6 
154 
1918 
47.70 
241.8 
19.7 
224 
1919 
80.22 
244.0 
33.1 
376 
An examination of the figures in Table IY shows: (1) 
That the selling-price of fertilizers increased gradually 
thru 1917, then in 1918 there was a marked advance, 
and then in 1919 a great upward leap; (2) That, while 
there was increase in the ton price, there was at the same 
time a marked decrease in the amount of plant-food per 
ton, and therefore the only proper basis of yearly com¬ 
parison is the price of plant-food per pound as shown in 
the fourth column of Table IY, in which we see that the 
cost of one pound of plant-food increased from 8.8 cents 
in 1914 to 33.1 cents in 1919; (3) That, taking the cost 
of one pound of plant-food in 1914 as 100, the relative 
increase year by year is shown in the last column of 
Table IV. The results show that in 1915 there was an 
advance of 25 per cent; in 1916 and 1917, about 55 per 
cent; in 1918, 225 per cent, and in 1919, 376 per cent. 
Therefore, during the year of 1919 the average cost of 
plant-food in complete fertilizers was nearly four times 
what it was in 1914. 
A SPLENDID LAWN TREE 
There is no tree more deserving of attention by nur¬ 
serymen than the Japanese Varnish tree, Koelreuteria 
paniciilata. It is not a large growing tree, or suitable 
for street planting, or even to be considered as a shade 
tree, although it does attain a height of thirty-five to 
forty feet, possibly larger. It is, however, more cus¬ 
tomary to see it about the size of a full grown flowering 
dog-wood. Its peculiar value and attractiveness is due 
to the erect clusters of bright yellow flowers which are 
borne profusely in the early part of July, at a time when 
all other trees are somewhat monotonous as regards 
color. The flowers are followed by conspicuous bladder 
like fruits. It is one of the most attractive lawn trees 
that can be imagined. It originally came from China 
where it is largely cultivated in the gardens of Peking 
and is common to Western China in the hot valleys. This 
should make it especially suitable for positions that are 
not uncommon on many lawns and where other trees do 
not thrive on account of the poor soil and dry conditions. 
It will withstand well both heat and drought and is ap¬ 
parently quite hardy. The tree is not an easy one to 
sell to a customer coming to the nursery to select trees 
before they are in leaf and flower. A straight one is 
abnormal, as they are usually very crooked and some¬ 
what unattractive during the winter, but the summer 
beauty more than makes up for this. 
It should be a splendid plant for the nurseryman to 
take hold of, work up and get stock and exploit it, as it 
is not at all common and may be said to be almost un¬ 
known to the average planter. 
CONTROL OF DANDELIONS IN LAWNS 
Experiments made at the Geneva Experiment Station, 
New York, during the past eight years show that dande¬ 
lions may be eradicated from lawns by proper spraying 
with a solution of iron sulfate. The treatment is com¬ 
paratively inexpensive, and does not materially injure 
the grass. Usually, four or five applications are re¬ 
quired, using one and one-half pounds of iron sulfate to 
each gallon of water. The first spraying should be made 
in May just before the first blooming period of the dande¬ 
lions. One or two others should follow at intervals of 
three or four weeks; and, finally, one or two more in 
late summer or fall. During the hot, dry weather of 
midsummer the spraying should be discontinued because 
of the danger of injury to the grass. A conspicuous 
blackening of the lawn which follows each spraying 
soon disappears if the grass is growing vigorously. Of 
the other common lawn weeds some are killed while 
others are but slightly injured by spraying. Unfortun¬ 
ately, white clover, also, is killed. 
Tests of certain methods of supplementary treatment, 
such as reseeding, liming of the soil, and the use of com¬ 
mercial fertilizers and stable manure, were made in con¬ 
junction with the spraying experiments. The results 
obtained warrant the strong recommendation that spray¬ 
ing be supplemented by the use of fertilizers and the ap¬ 
plication of grass seed in the spring and fall of each year. 
With proper management a lawn may be kept practically 
free from dandelions by spraying every third year. 
The cutting-out method of fighting dandelions 7s labor¬ 
ious and ineffective unless the greater part of the root is 
removed. Shallow cutting, unless done frequently, is 
worse than none at all, because each cut-off root 
promptly sends up one or more new plants. 
A full account of these experiments has been pub¬ 
lished in Bulletin No. 466. 
