Page:The Olive Its Culture in Theory and Practice.djvu/101

Rh level ground, will at the end of a year be three inches deeper than when put out. Planting at more than the ordinary depth will be injurious to the plant, and will often cause its death. For the perfect development of the olive, the soil must be pervious to the air, which is indispensable to the respiration of its whole organism.

Experiments have shown how the development of the same plant can be retarded or advanced, by planting it alternately deep and shallow. From these experiences it is conclusive that to condemn the olive to too great a depth in the ground is a grave error.

The rectangular hole of two feet long, and two feet deep, and a foot wide, will probably be the one commonly used in California, as it is much the cheapest.

Instead of holes a continuous trench may be dug, not less than three feet in depth; and the trees set out in it at the proper distance apart. Here the tender roots encounter no obstacle, the trench giving them free play each way and the result is, an astonishing development of the young tree. These trenches have proved particularly good on side hills. When we reflect that the life of this tree that we are starting on its road, will cover centuries, any expense incurred in promoting its growth at the beginning seems slight in comparison.

The wild seedling olive is unknown in California, but as the seed of the cultivated type almost invariably produces that of the wild, not many years will pass before these will begin to spring up on the hills about our valleys. The birds will be the disseminators. The writer has noticed the robin in particular. On cold winter days in the Santa Clara valley, this bird leaves the hills and appears on the Quito Olive Farm in great numbers, eating any fruit that offers itself, olives among others. The Spaniards are led to claim that the olive is indigenous to Spain because it is found growing wild on all their mountains, perhaps some future Californian will make the same claim for us, for the seed of the olive will certainly be spread far and wide in this way.