COLLEGE OF AGRICULTURE benj. ide wheeler, president 
 
 THOMAS FORSYTH HUNT, DEAN AND DIRECTOR 
 
 UNIVERSITY OF CALIFORNIA AGRICULTURAL EXPERIMENT STATION 
 
 ,E OF AGRIC 
 BERKELEY 
 
 CIRCULAR No. 86 
 
 OLIVES IN CALIFORNIA. 
 
 by 
 F. T. BIOLETTI. 
 
 Uses. The most profitable use of the olive is the making of ripe 
 pickles. Our green pickles, at present, do not compete successfully 
 with those imported from Spain. Oil is made from fruit too small for 
 pickling, and from that damaged by frost. It is profitable as a by- 
 product of the pickling industry. 
 
 Climate. The olive requires a warmer winter than the grape and 
 a dryer summer than the orange. In California, the olive region 
 coincides very closely with that of the raisin Muscat. A temperature 
 of 14° F. is the lowest that most varieties can stand, even when most 
 dormant. The cocl ana foggy summers of the coast region are 
 unfavorable. 
 
 Soil. Any soil that is well drained and not too shallow will support 
 the olive. It gives the best results in moderately rich, light soils, where 
 the roots can penetrate deeply. Very heavy or undrained soils are 
 unsuitable. Abundant lime is favorable. 
 
 Propagation. Young trees for planting may be started from seed 
 or from cuttings taken from any part of the tree. The sprouting of 
 the seeds, which is difficult, may be facilitated by soaking for several 
 hours in a 10 per cent solution of caustic potash, or by slightly crush- 
 ing the shell. Seedlings are grafted in the nursery when one or two 
 years old, and are ready for transplanting the following year. 
 
 Most nurserymen 's trees are raised from ' ' tips, ' ' or the extreme ends 
 of the branches. These are cut in the spring about five inches long, 
 all the leaves, except the top two or three, removed, and then rooted 
 in sandy loam under glass. -Cuttings of any size or age can be rooted 
 directly in the nursery, but are difficult to start if of smaller diameter 
 than 3 inches. 
 
 Grafting. Young seedlings are grafted at the surface of the ground. 
 Scions of two-year-old wood are used. Cleft, side or tongue grafting 
 will succeed. The grafts are tied with raffia, well waxed and covered 
 with soil. Larger seedlings may be twig-budded just above the surface 
 of the ground. Old trees may be crown grafted in the branches, or 
 twig-budded in sprouts produced by cutting off the branches the year 
 previous. Grafting should be done just before the starting of the sap 
 in the spring, budding a little later. 
 
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 Care of Orchards. The olive requires the same cultural treatment 
 as other fruit trees in California. The sqil should be ploughed as 
 deeply as possible before planting. Hardpan soil can sometimes be 
 made suitable by the use of dynamite. Thorough cultivation and 
 sufficient water are necessary. Irrigations are preferably few and 
 copious. 
 
 Pruning. During the first five or six years, the sole object of pruning 
 is to direct the growth of the plant into building up a "skeleton" of 
 proper form. This should consist of a single, straight clean trunk, 
 two to three feet high, bearing on top five or six main branches, sym- 
 metrically placed. Every shoot or branch, which is not needed per- 
 manently, should be removed as soon as possible, in order to avoid the 
 necessity of large wounds. Twigs are left on the trunk only so long 
 as they are needed to protect it from the sun. 
 
 In pruning bearing trees, the branches are first thinned sufficiently 
 to allow light to enter and promote annual growth in all parts. The 
 annual growth of the preceding year is then cut back about one half, 
 a little more with weak trees, and a little less with strong. Without 
 pruning, the crop is small and poor. With irregular pruning, the crop 
 is irregular. New growth is necessary each year for annual crops. 
 Pruning is the only method of "thinning" and is essential for large 
 fruit. 
 
 Harvesting. The crops of profitable orchards vary from one half 
 to four tons per acre. Large olives intended for pickling are gathered 
 carefully by hand into padded baskets or bags, hung on the shoulders 
 of the pickers, and hauled to the factory in barrels containing water. 
 The cost varies considerably with the size of the olives and of the crop 
 and averages about $15 per ton. 
 
 Oil olives are preferably gathered in the same way, but are often 
 shaken and raked off the tree and collected in sheets spread on the 
 ground. Unless the olives can be worked immediately, this method 
 gives inferior oil. 
 
 Diseases. The only serious disease infecting the olive in California 
 is the olive knot, which does much harm only to young trees, or to trees 
 in over-irrigated soil. Some varieties are affected by some little under- 
 stood fruit rots, which sometimes cause loss locally. Black scale is 
 very troublesome in foggy coast regions. In the interior it gives little 
 trouble. 
 
 Varieties. Only olives large enough for pickles are profitable. 
 The size of the fruit depends on the variety, the location, the soil and 
 on the methods of pruning, cultivation and irrigation employed. 
 
 Mission. The principal and standard variety of California. The 
 fruit is large, firm, of typical olive shape and deeply colored when 
 ripe. It ripens late in November in the earliest but not until Feb- 
 ruary in the later localities. The tree is vigorous and bears well in 
 most localities. There is much variation in Mission trees and it is 
 
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 important that stock for propagation should be taken only from trees 
 of known good performance. It is preferred by the pickle manu- 
 facturers because their methods are adapted to this variety. Its 
 main defect is its late and irregular ripening which exposes it to injury 
 from frost in most localities, and necessitates several pickings. 
 
 Sevillano. The variety from which the largest "Queen" olives of 
 Spain are made. When ripe, it makes excellent black pickles. It 
 resembles the Mission in shape, color and flavor, and differs from it in 
 its larger fruit and narrower leaves. It has not been widely tested, 
 but bears well in some places, and the fruit brings a large price. It 
 ripens early, but is said to be sensitive to frost. 
 
 Manzanillo. This variety has been planted extensively. The fruit 
 is a little larger than that of the Mission and deeply colored. Its short 
 apple-shape is considered undesirable, but the quality of the ripe 
 pickles is unexcelled. Its chief merit is that it ripens early. It bears 
 well in favorable locations, but fails in others. It is subject to a kind 
 of soft rot in the hotter localities. 
 
 Ascolano. This variety has very large fruit, exceeding even the 
 Sevillano. It has been planted in small quantities in several localities 
 and is everywhere reported as a good bearer. The fruit is of the shape 
 and size of a French prune. It contains very little bitterness or color 
 and requires special care in pickling. Some large plantings of this 
 variety have been made lately. 
 
 Other varieties producing large fruit, but little tested, are Obliza, 
 Macrocarpa, Picholine (true). Others sometimes large enough for 
 pickling are Columbella, Regalis, Gordal, Atro-rubens, Verdale, Santa 
 Caterina. The "Redding Picholine" is a small seedling, largely 
 planted by mistake, but worthless except as a grafting stock. 
 
 If more than one variety is planted, they should be arranged so 
 that they can be harvested separately. The utility of cross-pollination 
 is probable, but not demonstrated. Better bearing has been noted 
 following the introduction of an apiary into the orchard. 
 
 PICKLING. 
 
 The pickling of olives involves three steps: 1. Treatment with lye 
 to neutralize the acidity and bitterness. 2. Repeated soaking in water 
 to remove the excess of lye. 3. Salting by soaking in brines of gradu- 
 ally increasing strengths. 
 
 (1) Neutralization. Soak the olives for twelve hours in a solution 
 made by dissolving 1^ pounds of caustic potash in 12 gallons of water. 
 Very bitter olives may require a second treatment with fresh lye 
 (some Mission, Manzanillo, Sevillano) ; sweeter olives may require a 
 weaker lye (Ascolano, Columbella). With soft olives, 1^ pounds of 
 salt should be added to the lye. The olives should be kept submerged 
 by means of a floating cover and the lye drawn from the bottom and 
 poured over the top two or three times to insure equal treatment. 
 
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 (2) Soaking. When by examination of the color of the flesh of the 
 olives, it is found that the lye has penetrated nearly to the pit, they 
 should be removed to pure water. This water is renewed at least once 
 a day until the lye is removed, which requires two or three days. 
 With soft olives, a brine containing about two pounds of salt to 
 twelve gallons of water should be used for removing the lye. 
 
 (3) Salting. When the lye and most of the bitterness have been 
 removed the olives should be placed in stronger brine. It the olives 
 are to be canned or bottled, a brine containing about five pounds of 
 salt to twelve gallons of water is sufficiently strong. If they are to.be 
 kept in barrels ten or twelve pounds of salt will be needed. The 
 olives must be prepared for the strong brine gradually by being 
 placed in new brines every three to four days. Each brine should be 
 about two per cent stronger than the last. 
 
 Precautions. Strong lye tends to soften the fruit. A second 
 treatment in weak lye is better for bitter olives than a strong lye. 
 Salt has a tendency to harden the fruit and can be used to counteract 
 the softening effect of the lye with very ripe olives. Strong brine will 
 shrink and shrivel the olives, unless they are prepared for it by solu- 
 tions of gradually increasing strengths. 
 
 Color. With ripe pickles, the object is to have the color as uniform 
 and dark as possible. Uniformity is obtained by pickling each 
 variety by itself, by having the fruit as evenly ripe as possible and by 
 exposing the olives to each solution in as uniform a manner as pos- 
 sible. Spotting comes usually from unevenness of the lye treatment, 
 and especially from allowing some olives to float on the surface. 
 Depth of color is obtained by having the olives thoroughly ripe. By 
 exposing the olives to the air for several hours between the various 
 solutions, both the depth and uniformity of the color are increased by 
 oxidizing and browning the flesh. 
 
 With green olives, the air should be excluded as much as possible, 
 until the final brine is reached. A little vinegar improves both the 
 color and flavor of green olives. Some picklers advise the addition 
 also of a few bay leaves.