The olive is propagated by means of seeds, cuttings, grafting, and
budding. Propagation by seeds is seldom done in this country, as it is
so much slower and more troublesome than by cuttings, aside from the
fact that the desired variety may not result. The pulp has to be
removed, which is done usually by allowing the fruit to rot or by
softening with an alkali. Unless removed from the stone, the seed may
not develop for two years, otherwise the seed usually sprouts the first
year.
Propagation by cuttings is the commonest and easiest method, as the
cuttings root readily, and either old or new wood may be used so that
the cuttings may be large or small. Cuttings sent from Europe are
usually in the form of truncheons, and these may be cut into pieces like
firewood and will root.
The story is told of a grove in Morocco in which the trees exhibited a
peculiar arrangement. The reason given for this was that a king and his
army on the way to the Sudan had encamped for the night, and stakes or
pickets to tie the horses had been cut from a grove near by. The pickets
were left and had developed into trees. This seems probable enough when
it is considered that pieces of branches are taken, one end whittled to
a sharp point and driven into the ground, and that these pieces will
take root and develop. An olive company in California has recently
transferred 3000 trees, 26 years old, from San Joaquin County to
Oroville and Marysville. The trunks were sawed off about 18 inches above
the ground, and the roots 12 inches from the stump. In a planting made 6
years previously the same method was used and resulted successfully.
Where trees are found undesirable for some reason, resort is had to
budding or grafting. By these means the undesirable trees are not a
complete loss, and results are obtained sooner. Many times varieties are
obtained from Europe which on developing are not found suited to the
conditions in this country; these plants may be used as stock for
desirable varieties or some desirable variety is obtained which may be
propagated rapidly by these means.
The pruning must be done by persons of understanding, as the fruit is
borne only on the two-year portion of the branches, and provision must
be made
[Illustration: Gathering Olives]
to cut excessive growth in the season of too heavy development and
stimulate in the season of poor development. The pruning thus regulates
the growth of the branches which two years later will control the
production of the fruit.
Pruning of very large branches is sometimes done to admit more light and
heat to the darker, cooler parts of the tree. The small branches thus
provided in turn furnish nursery stock. Pruning is done in late winter
and early spring. From March to October no pruning is done, but the
trees are carefully tended through cultivation, irrigation, and
fertilization.
In California the young stock is set out in the groves in April, and
about 35 feet apart. During the non-bearing period, the land between,
which like all California groves, is kept in good cultivation and free
from weeds, is utilized frequently for other crops.
Though numerous stories are written of the remarkable ability of the
olive tree to grow and bear in exposed situations, and with only small
amounts of soil and water, the olive, like all other fruit trees,
requires both cultivation and an adequate amount of water if a constant
and abundant harvest be desired. As the groves are irrigated, the proper
amount of water may be supplied at all times. The water is conducted
through a system of underground pipes, which are provided with outlets
at the end of each row of trees. From these outlets the water is
directed into furrows to water the trees. As the irrigation is
conducted by underground pipes, the groves are easily cultivated.