13 
All chemical manures are employed at the rate of 14 litres 
of solution per vanilla vine. 
Two series of plots have thus been added to last year’s 
experiments. 
1. Plots 14 to 25—Parts of these were set out with cut 
tings from productive vines and tlie rest planted with cuttings 
from vines which had never flowered. This was done in 
order to ascertain whether the great number of vines which 
never flower, in a given vanillery, are tainted or not with 
hereditary characters and whether consequently the selectiou 
of cuttings should be made from vines of known productivity. 
2. Plots 27 to 52—Have also been set out and it is propo¬ 
sed to devote them to the study of the influence of different 
weeds on the growth of vanilla, independently of other treat¬ 
ment. It is the rule, on all estates, to allow grasses to grow at 
the foot of vanilla vines and to cutlass the weeds, once, two or 
three times a year without uprooting them. As the same spe¬ 
cies of grass are not uniformly adopted on all estates, the new 
experiments now on hand will serve to show what weeds are 
less injurious or more beneficial. There is no doubt that weeds 
evaporate a large amount of moisture from the ground—'(a blade 
of grass evaporating its own weight of water in one hour)—but 
the delicate vanilla roots must be protected from the rays of 
the sun an 1 it is the cooling action of the weeds which is looked 
for, lit spite of evaporation of the water from the soil. The 
question is however to find out by experiment what are the best 
grasses to be employed, both as regards the cooling action on 
the soil and the least interference with the roots and food of 
vanilla. 
In the experimental field, much trouble has been given by 
the roots of the shade trees (Albizzia moluccana and Parkia 
roxburghii) which accumulated in the ground near the vanilla 
roots and rendered the soil rootbound to the great prejudice of 
the orchid. As it would be a great pity to cut down these 
beautiful trees, which are 7 to 8 feet in girth, trenches have 
to be dug round the beds to get rid of the intervening roots 
which have also to be forked out inside the beds at regular 
intervals. The influence of some peculiar shade trees on the 
growth of vanilla has never been more clearly demonstrated 
than in the vanilla beds in question. These experiments 
show with what care shade trees for vanilla have to be 
selected. All large trees such as Parkias and Albizzias 
throw out a considerable number of rootlets, when manures are 
applied in the solid state to vanilla grown in their shade ; 
other trees such as Gliricidia maculata, used in some of the 
experimental plots as a prop, have not produced abundant 
rootlets on the surface, as in the case of Albizzia. There is 
every reason to believe that this small tree can advantageously 
replace aii the other props employed hitherto in the culture of 
the orchid. Their powerful vegetation does not in the least 
hinder the growth of the vanilla, vines an l there is nothing to 
show as yet, after 15 months’ trial, that, as a consequence of a 
great vegetative activity, the soil is dried up near the roots 
of the vanilla. This is due to the special root system of the 
Gliricidia cuttings which is formed of about half a dozen 
tuberous roots which sink deeply into the ground without 
interfering with the roots of the vanilla. Among the other 
great advantages of Gliricidia props, as compared with other 
props, the following may he mentioned :— 
1. The cuttings strike roots easily in all classes of soil, 
whether fully exposed to the sun or not. 
2. The branches are far apart and are admirably suitable 
for banging on the vanilla vines in the proper way. 
3. This tree is particularly free from insect and fungus 
pests. 
4. Many branches can ho pruned several times during the 
year and as the tree belongs to the leguminosae family the 
twigs and leaves removed can be used as green manure for 
vanilla on the spot. 
5. There are no other plants used as props which combine 
so powerful a growth with so little injury to the roots of the 
vanilla. Other leguminous plants, such as the Lucoena 
glauca, which is also sometimes employed as props, throw out 
a great number of root suckers with the result that the 
vanilla vines are soon choked and have to be replanted elsewhere. 
