Part 4

Back from the coast in the smaller valleys and on the hills where the coast fogs seldom reach, many locations may be found where almonds are producing successfully. These favorable localities are scattered, owing to lack of proper soil or moisture conditions.

Paso Robles District.—The one outstanding district in the coast hills where the almond is being grown successfully is in the country west of Paso Robles. There, at an elevation ranging from 900 to 2000 feet, where there is sufficient air drainage to the considerably lower land near by, the almonds are doing well. These plantings are, in most cases, on a comparatively heavy soil, sometimes approaching adobe, and underlaid by marl. This limestone formation is quite permeable to both water and the roots of the trees, and the rock itself acts as a sponge and holds considerable quantities of moisture. On the other hand, consisting of steep hills, the land is excellently drained and the trees seldom suffer from standing water around the roots.

The chief objection is that most of this land is very shallow, generally ranging from two to four or five feet deep. In some places almonds are found growing where the marl is so close to the surface as to be turned up by the plow. This makes the retention of moisture for the use of the trees a serious problem. The trees do not attain large size on such soils and the nuts are inclined to be somewhat smaller than normal. The steep character of much of the land makes tillage and spraying rather difficult and expensive. As long as the price of the land is kept down to a reasonable figure, the grower can afford to put more money into the care of both land and trees. It must be thoroughly understood that there are many localities close to Paso Robles that are greatly subject to frost and hence not at all suited to almond culture. This is especially true of the lands directly around and east of Paso Robles, and also of any of the comparatively low lands throughout the district.

SOUTHERN CALIFORNIA

The entire coast district of Southern California has practically proved itself to be unfitted for almond culture, except at elevations above 1500 or 2000 feet. The limiting factor seems to be the lack of a sufficiently definite winter season at the lower elevations. Trees are inclined to bloom too early in the season or before the winter is over.

Above 1500 or 2000 feet the increased elevation gives a sufficiently definite cold winter season and the trees tend to blossom at more seasonable times. Aside from scattered plantings in the hills of San Diego County and a few orchards around Hemet and San Jacinto in Riverside County, the principal plantings are at Banning and in the Mojave Desert.

Banning District.—Within a radius of three miles of Banning, with an average elevation of 2300 feet, where a plentiful supply of water is to be had from the mountains to the north, are a large number of orchards ranging in age from 2 to 29 years. The bulk of the plantings were made during 1910 and 1911. This is the oldest district in southern California and has proved itself to be well fitted for almond culture.

Antelope Valley and Vicinity.—The old plantings in the Mojave Desert are few and far between. They have, however, served as an impetus for large plantings in recent years many of which have turned out to be failures. This happened in many portions of Antelope Valley, west of Lancaster, on the Southern Pacific Railroad in northern Los Angeles County. Many more of these plantings are young and still have to prove themselves.

Orchard almond trees are never grown from seed, as they do not reproduce true to type, but are propagated by budding desirable varieties on seedling roots in the manner commonly employed in nursery practices for other stone fruits, like the peach. Every grower must decide, however, on what rootstocks he will plant his trees.

ROOTSTOCKS

There is much to learn yet regarding the behavior of the different roots under varying conditions when used as stock for the almond, but sufficient information has already been gathered to permit of certain recommendations being made.

Almond Root.—The greatest proportion of almonds in this state are on almond roots. Where the most desirable soil, moisture and drainage conditions exist it is best to select the almond root. It will live in comparatively dry soils, but cannot be expected to make a tree of large size or bear crops of nuts if the dry conditions continue. Where irrigation is not available, and the soil is deep and of proper texture, sufficient moisture may be retained in most years by cultivation to enable the tree to grow and bear fruit. When extra dry years come, the almond root may not enable the tree to grow or produce any better than would another kind of root, but it will carry the tree over a few dry seasons as well or better than any other. Then, when sufficient moisture does come, the almond root is ready to start the tree off in its normal course with the least loss of time.

The bitter almond is often recommended as being superior to the sweet almond as a stock. This claim has never been proved. Experiments indicate that there is fully as much variation between the bitter almond seedlings grown from seed from different trees as there is between seedlings from bitter and sweet almonds. Both are equally subject to attack by gophers. The grower’s chief object, therefore, should be to secure as healthy, vigorous trees as possible whether they be on sweet or bitter almond roots.

Peach Root.—Where the soil moisture is quite variable in different portions of the soil, or variable from time to time during the growing season, the peach root will probably be most satisfactory. Soils less than six or eight feet deep, or where gravelly or hardpan layers occur at less depths, are not satisfactory in most cases for the almond root, and under these conditions the peach root is better. The peach root is a little better where irrigation is practiced during the summer, and especially so where there is danger of slow drainage of excess water from the soil. The peach does not thrive with standing water around its roots, but will better withstand fluctuating or temporary extremes in water supply than the almond. Its union with the almond is entirely satisfactory. See figure 4.

Davidiana Root.—Within the last five or six years the United States Department of Agriculture has introduced the seed of a Chinese peach, Prunus davidiana, the root of which is more resistant to alkali than the ordinary peach. This has been found to unite readily with the almond, although experiments have not yet gone far enough to fully determine its true value. It gives promise, however, of being a very desirable stock for sections where alkali may be troublesome.

Undesirable Roots.—The Myrobalan plum has frequently been recommended as a stock for the almond on poorly drained soils. The two make a strong union, but the plum root grows much slower than the almond top, as indicated in figure 5. A comparison with figure 4, in which both trees are 48-year-old Languedoc, shows that the trees on Myrobalan root are pinched-in below the union while those on peach root are swollen at the base. Even young trees show the same pinching-in below the union. Almond trees on Myrobalan root do not make as large trees nor do they bear satisfactory crops in any portion of the state where it has been possible to compare them with the same varieties on other roots in similar situations.

The apricot is occasionally recommended because of its strong, thrifty growth, but it is a mistake to attempt to use it, as the union is not satisfactory. The trees grow thriftily for awhile, but before they reach full bearing they either break off at the union or are blown over above the union by moderate winds.

TOP-WORKING OLD TREES

Often through injudicious selection of varieties for original plantings, or for some other reason, it becomes desirable to work over old trees to more desirable varieties. This may be done by budding or grafting. In either case the tree may be entirely reworked in one season or one-half may be done the first season and the other half the next. The almond will recover fully if completely deheaded to a height of from five to six feet from the ground, provided it is not subjected to severe winds or excessive moisture in the soil. Winds are liable to break off the new top during the first year or two. Where these are dangerous it may be well to leave half of the tree on the windward side to be worked the second season. The remaining portions will help to serve as a wind-break until the top-worked portion of the tree has a chance to unite solidly with the stub of the main branch to which it is attached. Where winds are not likely to do damage it is generally the most economical method to work over the entire tree at one time. If the roots are subjected to excessive moisture conditions during the first season, the new growth may be unusually vigorous and much more likely to be blown out as a result of the heavy top and the poor attachment to the stub. “Sour-sap” may also be very serious. Under such conditions leaving half the tree the first season will enable it to distribute the growth more evenly with less undesirable forcing.

Whether the top-working shall be done by budding or grafting depends largely upon the wishes of the grower and the skill of the workman. Grafting will give a new tree more quickly than budding, because by the latter method a year is lost in growing a supply of new wood on the stubs into which the buds must be placed. By grafting, the new scions may start growing the first spring without any delay. Ordinarily the best method is to graft the trees the first winter and then, where the grafts fail to grow, buds may be inserted in the new growth which will come from the stub. During the first two seasons especially, great care must be exercised to keep out the sprouts that interfere with the growth of the scions. At the same time, all water-sprouts should not be removed during the first summer or there will not be sufficient leaf surface to perform the necessary functions of the tree. In addition, the scions tend to grow so rankly that they will be top-heavy and much more liable to be blown out by the wind, as shown in figure 6. This may largely be prevented by pinching the ends of the new scion growth during the early summer to force lateral branching. At the end of the first year all water-sprouts should be removed leaving nothing but the growth from the scions.

PLANTING

The usual preparation given land for orchard purposes prior to planting should be applied to land being prepared for almonds. Special care must be given to insure thorough aeration of the subsoil by breaking up all hardpan, plow-pan or other compacted layers in the soil, where possible.

Distance.—Almonds in most soils should be planted 30 × 30 feet on the square. In rich, deep soils the trees quickly fill the intervening space, the roots occupying the entire soil area long before the tops touch. In poor, shallow soils, or soils deficient in available moisture, the trees may not occupy the entire area above ground, but the roots will require more horizontal feeding space to enable them to make the size trees and bear the crops that they should.

Trees planted too close together often abstract the moisture from the soil before the growing season is completed. This shortage of moisture, with the aid of mites, commonly called red-spider, causes the loss of the leaves long before they normally should drop. Under such conditions the fruit buds are unable to make the vigorous growth which they should. These weak buds are unable to endure the degree of frost or other unfavorable conditions that stronger ones withstand without serious injury.

The trees must have plenty of sunlight and air. If planted too close, the trees tend to grow too high, each one striving for the light which is only available from above. In figure 7 the upward tendency of the trees is clearly shown. Such trees, if pruned as they ought to be, have a much greater tendency to send out numerous water-sprouts than trees which have plenty of room for the tops to expand laterally. After the tops of the trees interlock and shut out the sunlight from the lower portions, the smaller branches and fruit spurs in those parts gradually weaken and die, and eventually the entire crop is produced on or near the tops of the trees, where direct sunlight is available, as shown in figure 7. The excessive upward growth of the trees, with the consequent forcing of the fruit bearing to the top, not only greatly increases the difficulty and cost of pruning, spraying and harvesting, but reduces the possible bearing surface of the trees.

Setting the Trees.—The utmost care is necessary in setting out the trees to secure a uniform stand of vigorous trees. The trees are planted much the same as other deciduous orchard trees, but care must be used to spread the roots well to secure a thorough compacting of the soil around all the roots, and to see that the trees are not planted deeper than they were in the nursery.

CULTURE

Soil Handling.—The almond is one of the most exacting of fruits as regards its cultivation. The assumption is very often made by growers that because the tree will live through periods of prolonged drouth, it will also thrive under careless or poor methods of cultivation. That this is entirely erroneous may be inferred from the fact previously referred to that the almond draws more heavily upon the plant food of the soil for the ripening of its crop than any of the common orchard fruits. Experience has abundantly proved that many almond orchards are not bearing profitable crops because the requisite soil constituents are not available in sufficient quantities during the long growing season. The reasons for this condition may be one or several. First, there may not be sufficient moisture available throughout the season, or it may not be distributed evenly or in sufficient amounts throughout the entire soil area. Second, there may be insufficient aeration of the soil; and third, there may not be sufficient humus to fix the soluble plant food in the soil and render it readily available as needed by the roots.