THE GROWING OF ORNAMENTAL PLANTS
It has been said that a person must have a knack for growing plants to succeed at gardening. This may be true in the case of some of the more difficult subjects, and there is sometimes an element of luck involved in getting a transplanted tree or shrub off to a good start. However, good care and the use of up-to-date methods will help to prevent failures. Attractive gardens and home plants do not occur by chance but represent painstaking effort on the part of some plant enthusiast. The utilization of native plants in landscape beautification is probably the least expensive and the surest method. The foundation stock can sometimes be obtained for the digging, and once it is established, will endure more neglect and unfavorable growth conditions than imported material. The more skilled gardeners will certainly want to grow some of the more unusual exotics, especially tropicals. Regardless of what material is used, the grower is certain to feel a thrill of accomplishment once the project is well under way.
Since the soil is the medium in which our plants must grow, it might be well to consider a few facts concerning soils; their origin, properties, and uses. Geologically, soil is disintegrated rock, containing varying amounts of organic material that has been worked over by the many soil building agencies. From the purely agricultural viewpoint, soil is the medium in which plants grow and may be of either mineral or plant origin, usually both. Our Valley soils are principally alluvial, but there has been some working over of certain types of wind action. The physical and chemical properties of soils determine their usefulness for agricultural purposes and should receive due consideration. The silts and clays are composed of fine particles and are rather poorly drained, while the sands, loams, and gravelly soils have larger particles and are usually well drained.
Our most desirable Valley soils are loams, and the sandy loams are better drained and easier to handle than the more plastic clay loams and clays. All of our soils are slightly saline and contain relatively large amounts of calcium carbonate. This means that our soils are alkaline as opposed to the acid (low pH) soils common to most of East Texas. Since some plants have definite soil preferences, the grower should select his material accordingly, or should plan to modify the soil to suit the needs of the plants he decides to use. This can be done by using certain acid forming materials and soil conditioning chemicals but is too expensive for wide scale use.
Maintaining proper water relationships is a most important part of soil management. Making provisions for adequate drainage and attending to the irrigation program are the important factors affecting soil moisture. Weeding, cultivating and mulching are important principally as they affect soil moisture and soil temperatures.
Sources of plants
There are many sources from which plants may be obtained. Probably the least expensive method is to obtain seed of desired sorts and start a tin can nursery. Where the time element is important, gardeners sometimes go out into the brush country and dig out desirable native plants. This has the double difficulty of usually securing an inadequate root system and of depleting the countryside of valuable plants. For these reasons, progressive gardeners prefer to choose from the wealth of material at any one of the nurseries that cater to home gardeners. Regardless of where the material originates, the grower should assure himself that the plants are free from noxious pests and diseases that might be introduced into his garden along with the new plant material. This is the principal reason for having nursery inspection laws.
The reproduction of plants is a relatively simple matter in some instances, but certain subjects may require considerable horticultural skill for success. Many annual plants and some of our most satisfactory woody plants are propagated from seed. Others can be grown rather easily from cuttings or layers, while some of the more difficult subjects may require marcotting or cuttage under controlled conditions.
In growing seedlings, one should start with soil that has been sterilized by heat or with carbon bisulfide fumigation. The soil should be composed of a mixture of equal parts by volume of gravelly sand, good garden loam, and peat-moss or compost. This also makes a good potting soil for use in the tin can nursery. The seed may be planted in shallow flats or boxes, but it is often desirable to plant the seed of large plants in quart oil cans from which the lids have been removed. To insure drinage and facilitate transplanting, the bottoms of the cans should be cut along three-fourths of the perimeter. The larger sized cans make excellent receptacles in which to grow plants that must attain considerable size before being moved to their permanent locations.
The growing of plants from cuttings may be accomplished in the open ground, but better results are usually obtained where some sort of cutting frame is used. A small hot-bed, equipped with burlap and lath screens in addition to the sash cover makes an excellent propagating frame. Coarse builders sand containing about ten per cent by volume of peat-moss is satisfactory rooting medium for most subjects. Keeping soil moisture and overhead humidity at the proper levels requires painstaking care and good judgment. Punctuality in attending to the needs of the rooting cuttings is highly important.
It is a relatively simple matter to transplant "balled" or potted plant material, but the setting of "bare root" plants is a more difficult job. Since most of our Valley soils are quite fertile, it is not necessary to dig large holes and fill them with top soil or specially prepared potting soil. This may be desirable when replacing a plant that has died from root disease, but it is usually best to use a hole only slightly larger than the ball of earth about the plants roots. The important point is to set the plant on fairly firm ground and then tap the soil about the roots very carefully, so as to avoid air pockets. A sufficient quantity of water should then be poured about each plant, so as to wet and pack the soil to a depth of at least eighteen inches. Mulching and shading will hasten the recovery of weak subjects that were not hardened off before being moved to their permanent locations. Watering with weak nutrient solution (one level teaspoonful of 11-48-0 per gallon of water) will also help force the growth of newly set plants.
Probably the most important cultural requirement of ornamental plants is the maintenance of adequate amounts of soil moisture. Sprinkling the surface of the soil with a lawn hose is not an efficient way of applying water, as too much time is required to thoroughly wet the soil within the root zone of the plants. Where irrigation water is available, the use of three-inch conductor pipe or three-inch canvas pipe or hose is a most effective way of distributing water over the surface of lawns or about the roots of ornamental plants. This is a much better system than flooding, as adequate amounts of water are supplied without water-logging the entire soil mass.
A certain amount of weeding is essential in the growing of plants, but stirring of the soil is not essential and may cause actual damage in the case of jungle plants such as the avocado. Scraping of the soil with a hoe or removal of weeds with an asparagus knife are effective ways of eliminating undesirable weeds.
Since many of our plants are being grown out of their natural habitat, they may require special protection from wind, cold, sun, insects, and disease.
Plants known to be susceptible to wind damage should be planted in sheltered locations or near the center of group plantings. Likewise, shade loving plants should be planted where they will not have to endure the full effects of the suns rays.
Protection of plants from cold presents a more complicated problem, as some of our most desirable ornamentals are severely damaged by temperatures only slightly below the freezing point. Probably the simplest method of protection from cold is to bank trash-free soil about the base of the plants. Also covering the plants with a basket or hamper will afford considerable protection during cold spells of weather. Both methods conserve the stored heat already in the soil. Wrapping the trunks of plants with paper or other insulating material affords little or no protection during prolonged periods of cold. The burning of fuel oil in cans, buckets, or patented heaters is an effective but rather expensive method of preventing cold damage to valuable plants. In most cases it is not necessary to start heating until the temperature has dropped to about thirty degrees F. The important thing is to start heating before damage has occurred and to have sufficient fuel available to heat throughout the period of the emergency.
The control of insects affecting ornamentals is a subject unto itself. However, every home gardener should know what materials are available for the control of most insects that attack our plants. Most seed dealers have a fair knowledge of insects and insecticides and will help growers identify pests and map out control programs. There are a number of excellent materials which can be used in the control of both insects and diseases. When in doubt about the control of these plant enemies, the grower should consult his County Agent or the Experiment Station
The control of plant diseases is fully as complicated a process as insect control. Certain abnormal conditions of plants are due to internal causes, usually nutritional deficiencies. These can generally be corrected by adjusting the fertilizer program to the needs of the plant or by adding soil conditioning materials that will adjust unfavorable conditions or release needed plant nutrients. Sulfur-manure compost, peat-moss, gypsum and iron sulfate are a few of the materials commonly used in treating nutritional diseases of plants. These materials are most effectively applied by placing them in holes bored or punched into the soil about the crown roots of the plant. Parasitic diseases of plants are due to invasion of the plant tissues by some sort of living organism. Soil sterilization has been mentioned as a means of avoiding infection from soil borne diseases. "Damping off," root rot, wilt, and root-knot are a few of the diseases which may be controlled by soil treatment. Foliage diseases such as mildew, leaf spot and rust are due to fungi (molds) and may be controlled by spraying or dusting the plants with protective fungicides, most of which contain copper in some form. There are many reliable fungicides which may be purchased at most seed stores. Information concerning their use may be obtained from your dealer or from representatives of the Texas A & M University serving this region.
Ornamentals for the Rio Grande Valley