This section is from the book "The Standard Cyclopedia Of Horticulture Vol2", by L. H. Bailey. See also: Western Garden Book: More than 8,000 Plants - The Right Plants for Your Climate - Tips from Western Garden Experts.
It is always preferable to propagate dates from suckers unless one desires to originate new varieties, not only on account of the knowledge of the sex (it being hardly necessary to state that the sex of a sucker is the same as that of the plant from which it is taken), but on account of the ability to make a selection in the variety and quality of the fruit.
Dates are easily grown from seed if the ovules have been properly pollinated. Seeds may be planted in any month immediately after they are taken from the fruit, particularly in the mild climates of the Salton Basin, Lower Colorado Valley, and Salt River Valley. Unless the conditions are good, however, it is better to stratify them in a box between layers of moist sand and allow them to remain for three to six weeks in order that the seed-coats may be softened. It is important, however, that in the stratifying-box the seeds do not sprout, as they are easily damaged after sprouting takes place. The seed may be sown in nursery rows and the young seedlings transplanted after one, two or three years; or if the field is well prepared, and has good irrigation, the seed may be planted directly in the fields where the palms are permanently to remain. If they are placed directly in the field, it is well to plant them in rows 25 to 30 feet apart and to allow the young plants to stand
3 to 5 or 6 feet apart in the row. When the dates come into bearing, the undersirable ones and the males may be removed and the probability is that a sufficient number of good varieties will remain to make the row properly continuous; and the rows will be far enough apart for the regular or permanent plantation.
Suckers or offshoots are taken from the base of the young palm (Figs. 1223, 1224). One to several suckers may be removed each year, averaging two to four for the productive period, and when they are three to six years old and have begun to develop roots of their own. All species belonging to the genus Phoenix are difficult to transplant with uniform success. Frequently as high as 50 per cent of transplanted dates die even when watered daily and given the best of care. In planting suckers with the best of attention, a percentage die; while without care not one in a hundred will grow. It is due not so much to the lack of experience in removing the suckers as to lack of proper care after removal, that so large a percentage fail.
Suckers may be removed at any time during the spring or early summer, or even in the winter, if proper care be given them after removal. If they are to be planted in the open ground it is advisable to remove them in spring or early summer, April probably being the best month. In winter, when the plants are at a standstill, the suckers may be removed with comparatively small loss, if the "bulbs" or bottoms be not less than 4 inches in diameter. It is necessary, when suckers are removed at this season, to set them in rather small pots, so that the earth, which should be given a daily soaking, may have a chance to get warm quickly. The pots should be kept in a dry greenhouse, or, better yet, imbedded in a hotbed of manure, covered with the customary frame and glass. In all cases the leaves should be cut back to 6 to 12 inches in length, and sometimes they are removed. Transplant only when the ground is warm.
If proper attention can be given it is best to plant large suckers where they are to remain, as a second chance for loss occurs when they are transplanted from a nursery to the position that they are finally to occupy. An iron bar weighing thirty to forty pounds, and flattened to a 4-6-inch cutting end, may be used to cleave the offshoots from the tree. The leaf-stalks should be cut away, exposing the bulb of the sucker, care being taken not to injure the bulb in removing. One should cut in rather deeply at either side, not being afraid of injuring the old plant, cutting out a V-shaped portion extending from the base of the bulb downward for a few inches. Wounds may be painted with coaltar to prevent bleeding and evaporation. It is important, when planting the suckers in the field, to set them so high that the crown-bud will not be covered with water during irrigation, in order to avoid decay and death.
Fig. 1224. Deglet Noor date palm about eight years old, with offshoots and ripe fruit.
A successful method of rooting the suckers is to bank up earth about the base of the parent tree and above the base of the suckers, and keep moist by watering daily to induce formation of roots. Suckers may be partially severed from the old stock before the banking is done, or after the roots have started. When the roots are well grown, the suckers may be transplanted with little loss.
The suckers will grow perfectly well, however, if no roots are left attached. The offshoots may be cut away from the parent plant, with all the leaves removed, and leaving only the bud in the center or at the apex surrounded by the leafstalks. Such offshoots will stand very much exposure and may be shipped long distances without being packed in moist material, care being taken that the boxes are so filled with packing that they will not be jammed or bruised in transportation. After they are planted, they should be kept constantly moist about the bottom and should not be allowed to suffer any check. The Arabs apply water every day for thirty or forty days and then continue to irrigate each week until the following winter, care being taken not to water too much. If these precautions are taken and if the offshoots are planted in warm ground, there need be very little loss. They should never be set in the open ground when the soil is cold, as in fall or winter. If the offshoots are to be taken off at that time, they must be grown in pots or in some similar way, as described above.
The growing of dates.
The date palm grows in nearly all kinds of soil, if only the climatic conditions are right. If it be sufficiently irrigated and have the requisite amount of heat, the soil seems to be a secondary consideration. In general it may be said, however, that sandy-loam soils of the desert, with a small percentage of clay and slightly charged with salts, are preferable to rich and heavy soils, suitable for growing ordinary crops. The question of water is of great importance in the culture of dates, as it is necessary that the roots of the date palm be in moist earth throughout the year. In general, the amount of water required for successful culture is considerable. If sufficient water cannot be supplied by natural methods, one must resort to irrigation. Water should be supplied at frequent intervals throughout the year. However, the most should be supplied in the spring before blooming, and in the fall prior to the ripening of the fruit. The amount of water for each palm depends so much upon soil and local conditions that an estimate would be worthless. Care should be taken not to irrigate to excess at the time of blooming and immediately after, as it will militate against the successful setting of the fruit.