Drug Plants Under Cultivation

by W. W. Stockberger

For culture on a commercial scale the climatic requirements of camphor are practically the same as those of citrus fruits. The tree can be grown in almost any soil, but the maximum growth is secured in soils which are rich and well drained. When planted for commercial cultivation new land is preferable. The following statements are based upon actual experiments and observations on the growing and production of camphor under conditions found in Florida.

Camphor seeds ripen about the middle of October and should be planted while fresh, a better germination being obtained when the pulp is removed. The seed bed should be selected with care and the precaution taken to have one that will give sufficient moisture during the dry season and yet be well drained. For small seed beds of 2 or 3 acres or less it may be practicable to provide irrigation. Excellent stands of seedlings have been obtained on slightly rolling land which originally was covered with "blackjack" oak.

About the first of September, or somewhat earlier if conditions permit, the land should be well plowed and thoroughly worked down with a disk harrow. Just before the seeds are planted it should again be worked over and all roots of Bermuda grass or other weeds removed, since rapidly growing grasses or weeds will absorb so much moisture from the soil that the seeds can not germinate.

The seeds begin to ripen during the first part of October and are usually in a fairly well ripened stage by the last of that month. From this time until the heavy frosts they can be gathered and planted with safety. Seeds gathered after heavy frosts have been planted successfully, but it is not advisable to take the risk of too hard a freeze. In determining the time to gather seed a simple test is sufficient. Seeds that fall into the hand when the cluster is slightly twisted are ripe enough to plant.

In planting, a cotton-dropping machine, modified somewhat to meet the new requirements, may be used. The machine is set to plant the seeds 2 or 3 inches apart and cover them 1 inch deep in rows far enough apart to permit horse cultivation. The plants begin to come up in about three months, but four or five months are often required for a full stand. As soon as the plants can be distinguished in the rows cultivation is begun, which at first is done by hand with either a wheel or hand hoe. Later, as the plants attain size, a horse cultivator can be used, but a certain amount of handwork is necessary throughout the time the plants remain in the seed bed. When the plants are well started they should receive a good application of sheep or goat manure or of high-grade fertilizer.

The first season a growth of from 3 to 18 inches may be expected, the irregularity of development depending on the vitality of the seed, variation in the soil, and numerous other factors. The plants are allowed to grow in the seed bed usually for a year and are then transplanted to the field. In transplanting it is customary to separate the plants into two grades, "sturdy" and "weak," planting each grade in a field by itself. By doing this the replanting is simplified, since the sturdy stock requires but few trees for replanting and the weak stock, which will require considerable replanting, is all in one section.

Previous to transplanting, the land is well prepared by deep plowing and thorough harrowing, and rows are laid off 15 feet apart. The young trees are set in these rows 4 feet apart, either by hand or with a tree-setting machine. This machine is simply a tobacco-setting machine fitted with a trench opener set to open a furrow 8 inches deep, in which the trees are placed. The trees used for transplanting are headed back to within 1 inch of the crown, and the lower end of the taproot and all large laterals are removed. The taproot of the tree as planted is thus reduced in length to 8 or 10 inches and varies in diameter according to the vitality and previous growth of the seedling. Transplanting should be done in the winter months, when the trees are dormant.

Cultivation is begun as soon as the trees put forth shoots in the spring and continued until the rainy season of each year. After the rainy season the plants are again cultivated and all grass and weeds removed. At times cultivation is necessary during the rainy season in order to keep the trees from becoming smothered and killed by the fast-growing weeds. One-horse cultivators drawn by mules or a gang cultivator drawn by a light tractor may be used.

In three or four years, after transplanting, the trees should be from 7 to 8 feet high. They are then trimmed by means of a special machine[3] to form an A-shaped hedge and the trimmings distilled for the oil and camphor gum. Trimming is carried on when the trees are in the dormant stage, which is twice each year, usually November to January and May to June. The summer dormant season is somewhat irregular and governed entirely by local conditions.