We have observed many persons copiously watering young trees and
garden plants.
1. In many cases much water is a positive injury. The roots draw up a
larger supply of liquid than there is vigor in the tree to digest or
appropriate. In such cases the tissue is enfeebled, the roots decay,
and the tree perishes in the trying heats of July and August.
2. It often happens that wetting the tree itself is much better than
watering the root. Take a watering-pot and drench the leaves, and
limbs and trunk, several times in a day. In a small tree a large bunch
of cotton or rags may be put in the crotch and saturated with water.
It will gradually trickle down the stem, and also evaporate, keeping
the leaves in a moist medium. This trouble is worth while in case of
rare trees difficult to be obtained. A tree perspires as really as an
animal or a man. Every leaf is furnished with _stomata_ or pores, the
number and size of which determine the amount of perspiration. Of
course, as they vary in different plants, there is a corresponding
difference in the amount which they perspire. Plants which grow in
exposed situations, scorched by the sun, have a structure which admits
but slight perspiration, while those which grow in the shade and in
moist places perspire copiously.
It is upon this state of facts that watering the tree itself is
beneficial. The exhalation from the leaf is diminished, and sap
retained within the tree. Beside this, the leaf and young green bark
absorb some moisture.
3. Where watering is resorted to it should not be upon the surface;
especially is this injurious in clay soils. The moisture is
immediately exhaled, and the sun hardens the wet earth into a crust,
nearly as impervious to light, and air and moisture, as if it were
sheet-iron. Let a slight trench be opened, and after the water has
sunk away, replace the earth and pulverize it. In this way no baking
will take place.
4. But the best method of watering by the root, is that which is
technically denominated _mulching_. Cover the surface of the ground
beneath the tree or shrub with three or four inches’ thickness of
coarse, strawy manure. If watered through this the earth will not
bake; the moisture will not evaporate; the root will be shielded from
the sun, and enriched by the infiltration of the juices of the manure.