Desert

Desert Plants

The undisputed king of the San Felipe desert is the cardón cactus. Reaching heights of 60 to 75 feet and weights of 20 to 40 tons, cardón is the world’s largest cactus. Flowering with the first change of winter soil temperatures, they don an array of white trumpet-shaped flowers along most branches and thereby begin a complicated process of reproduction.

The tallest of the species are located along Baja Sur’s Magdalena Plain while our local cardón range to 30, 40 and 50 feet in height. With a lifespan of 300 years, a few of our local giants witnessed the coming of the Spaniards at the close of the 17th century. If cardón is king, Cholla is the knave of the cactus world with more than 100 varieties although considerably less than that have been identified in the San Felipe.

A towering cardón cactus at the mouth of Arroyo Huatamote near Laguna Percebu, south of San Felipe.

Another important cactus is the Prickly Pear or Nopal, as it is called in Spanish. With large, flat, pad-like stems, nopal are edible and widely used as a food source. The fruit is made into jelly and syrup and the seeds can be used in soups or ground into flour. This plant has medicinal properties and has been used to bind wounds, treat warts, and aid in childbirth. What’s more, it has been scientifically investigated for numerous medical treatments and commercial properties.

Another local plant is Senita (garambullo), also known as The Old Man Cactus Their tall thin columns grow to heights of fifteen feet and put on beards of long gray needles. Sprouting new vertical stems when a column falls over, some clusters are over a hundred years old. This spring bloomer has small pink flowers that open at night to accommodate bat pollinators.

There are 125 plant species in Baja California that grow naturally nowhere else in the world. Although not one of the 125, Ironwood was found in abundance here but subsequently eliminated (for its use as firewood). The fruit, a long twisted pod, is edible and tastes like peanuts. The wood is dark, hard (as iron?), and beautiful wood carvings are made from it. The Elephant tree (torote) is a name given to several aromatic members of the Burseraceae family. Getting its nickname from the fact that its branches are proportionally thicker than their length, this low flowering tree is used as an ornamental throughout the southwest.

One species, at maturity, develops a beautiful yellow exfoliating bark. The Foothill Palo Verde is by far the most numerous of the trees in the area. This low, densely branched tree has beautiful small yellow blossoms in late spring. It provides much needed shade and shelter for numerous other small plants and animals. There are several varieties of mesquite throughout the local area including those with and without bean pods. One of them, favored by the insect “Tarantula Killer,” literally weeps from upper branches throughout the summer.

Another unusual plant found in the San Felipe is Ocotillo, a woody shrub with many branches sprouting from a circular base. Resembling a cluster of long, spiny broom handles, ocotillos have raceme’s of reddish-orange blossoms. Many of the locals use the stems for fence posts and, if replanted and watered frequently, will re-root and create a living fence. The indigenous make a tea from the plant’s flowers and seeds.

Further, the blossoms can be eaten raw. Ocotillo, in human terms, is but a 10,000 year old grandchild of the plant Native Americans called Boojum (idria columnaris) which, in Spanish, is known as Cirio. The desert Lavender produces long slender green leafed branches with tiny purple flowers at the tip. Found in washes, this aromatic shrub is always a pleasure to find. Another shrub/tree found in the washes is the Smoke tree (Palo Triste in Spanish). This prolific plant is generally unattractive until brighted by Spring rains when it literally radiates with a gray-green hue and made the more beautiful with an inundation of tiny purple flowers.

The Creosote Bush is the most predominate shrub in the region. Called Gobernadora in Spanish, it is a diffusely branched evergreen with bright yellow flowers in late winter and early spring. Probably the most medicinal of all plants in the area, it has analgesic, diuretic, decongestant, expectorant, antiseptic, antimicrobial, and bactericidal properties. It is used locally to cure everything from stomach aches to stinky feet. The Creosote Bush clones new bushes that form rings spreading outward from the oldest plant. Some of the largest rings of Gobernadora are estimated in excess of 11,000 years of age.

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Desert Soils

Soils play a major role in a desert ecosystem. A soil is the result of weathering of geologic material. Once exposed, the forces of nature, break this material into ever smaller pieces. Soil is not just the accumulation of this degraded material however.

Over long periods of time, through the interplay of organic and inorganic and forces, soils are formed. Soils that look different and have different properties from their geologic parent material are said to be mature soils. A good example of this is the rich farmland of the American Midwest. Young soils on the other hand have characteristics similar to their parent material.

The play a at low tide near Punta Estrella, south of San Felilpe.

The desert has examples of both mature and immature soils. For example, the sand in a shifting dune is so young it is not considered soil because it is not sufficiently different from it’s parent material. Typical desert soils are called aridisols. Aridisols are formed under the influence of strong winds, scattered but torrential rains, and high temperatures. They have a surface layer low in organic matter, as well as other layers, or horizons, including clays, salts, and minerals. The materials in these layers often are cemented together forming water-impervious hardpans.

It is important to realize that soils are not dead, sterile substances. Algae, lichens, and fungi all live within the soil and become a part of it. Two important examples of this fact are mycorrhiza and crytogramic soil. Mycorrhiza is a fungi that grows in the same location as, and closely resembles, plant roots. This fungi forms a symbiotic relationship with higher plants, helping them take up water and phosphorus. Crypyogramic soil can almost be described as living soil. This combination of soil, algae, and lichens produces a gas, forming a crusty, tile-like surface. Full of tiny pockets, this is a storehouse for organic material. Its harder outside crust makes it less susceptible to wind and water erosion.

Another important aspect of desert soil development is dentrification which is the process of compaction of soil by natural elements. Light rainfall and baking sunlight cause the ground to compact. Over time, a fairly hard-rigid surface is established. Ironically it is more important to have compacted soils in the desert than loose soil. The reason is wind and water erosion. The nutrients trapped in cryprogramic and dentrified soil can easily be lost when churned into powder by grazing animals and motorized vehicles. Because much of the San Felipe region was under seawater for millions of years, local soils are more alkaline than other soils, low in lime, organic matter, nitrates and phosphorus while high in potassium, zinc, iron, manganese and copper.

Gardening With Desert Soils

If you were to examine your desert garden soil, you would find it composed of tiny particles of dirt, sand, gravel, rock and some residual percentage of salt. The fact is, former sea floor is composed of approximately 80% silica, 8 % alumina, 4 % sodium, potassium, calcium and magnesium oxides, 3% iron oxide, 1 % titanium oxide and about 1 % of all other oxides and a varying amount of residual salt.

Whereas it contains sufficient percentages of soluble sodium, potassium, calcium and magnesium oxides to meet the needs of natural vegetative cover, the normal decay of plant residues-and the resultant production of carbonic, nitric and sulfuric acids-is restricted by the presence of secondary clay minerals that inhibit the development of active acidity.

As regards gardening with desert soils, the initial question is whether your soil is alkaline or acidic. Acid Intensity determines which plants can be grown in the soil as it is. As you drive back and forth across the desert, you will notice different plants growing in different areas. Because every plant has its own nutritional requirements, the appearance of different plants tends to identify the acid intensity of a given soil.

Acid intensity is a product of the solubility of acid-containing minerals in soil and that acid’s degree of ionization or what is otherwise known as the HYDROGEN-ION CONCENTRATION of a soil solution. Hydrogen-ion concentrations are usually ex-pressed as pH values. A standard pH chart would show a series of numbers ranging from 1 to 14 with 1 being highly acid, 14 being highly alkaline and 7 being neutral.

Because pH numbers are a logarithmic representation, 5 is ten times more acid than 6 and 10 is ten times more alkaline than 9. If you were to examine plants you found growing in the desert, you would learn the dominant plant species-comprising nearly 90 % of the ground cover surrounding San Felipe-are bursage and creosote bush which tend to indicate a relatively low presence of alkalinity. Other plants common to the same region are brittlebush, cardón, cholla, desert mallow, indigo bush, ironwood, mesquite, ocotillo, palo verde, pitaya agria, smoke tree, elephant tree, and yucca. It is due to these plants-which grow only in acidic rather than alkaline soils-that we know the desert surrounding San Felipe will support or can be made to support a variety of garden plants.

To prepare your flower or vegetable garden bed for planting, take a soup can size soil sample to an American county agricultural agent for analysis where, for a small fee, he will be able to tell you precisely how alkaline or acidic your soil is, how to correct it and what soil builders and fertilizers you should use. Should you choose not to spend money on soil samples, we recommend the addition of 1 lb of agricultural sulfur and 2 bales of peat moss per one hundred square feet of garden bed turned to a depth of 2 feet. All plants require nitrogen for flower and fruit development, Phosphoric Acid for stem, branch and leaf growth, and Potassium for root and stem development. You will find those nutrients in mixtures sold either a Commercial or Organic fertilizers.

If you examine a commercial fertilizer label, you will see it lists a mixture of these three all-important chemicals by percentage numbers such as 6-10-4 which indicates 6 lbs of nitrogen per 100 lbs of fertilizer mix-usually derived from ammonium Nitrate, 10 lbs of phosphoric acid per 100 lbs of mix-usually derived from chemically formulated from Treble-superphosphate, and 4 lbs of potash per 100 lbs of mix-derived from Sulfate of Potash. In addition, most chemical fertilizers contain inorganic filler material to add weight to the bag.

Organic fertilizers include manure, ground cottonseed meal, ground rock phosphate and Muriate of Potash. Manure, whether cow, steer, horse, chicken, turkey or human, is an organic fertilizer containing 2% nitrogen. Two popular fertilizers-Mil Organite, originated years ago in Chicago, and Soil Organite, originated by California’s Orchard Supply Company, are mixture of dried human fertilizer, also known as sewage sludge, and commercially mined Urea to create a 6% nitrogen fertilizer that is perfect for new lawns and other seedlings.

Because organic fertilizers release their chemicals slower than chemical fertilizers, you usually do not need more nitrogen than they contain although commercial sales people have long ago convinced the American public they need a 10% nitrogen mix for tomatoes, 6% for strawberries and other amounts for other plants.

Higher percentages are required by farmers striving for maximum crop production in the shortest possible time. The problem with chemical fertilizers is a) they remain in the soil for relatively short periods of time whereas the slower releasing organic fertilizers remain in the soil considerably longer. b) They usually contain undesirable chemicals that can compound a problem created by desert soils. That is, chemical fertilizers contain chemically formulated salts such as those found in Super phosphates and Sulfate of Potash.

If you are a serious gardener, who wants the best vegetables or the prettiest flowers your garden can produce, use organic fertilizers at a rate of 6 lbs of cottonseed meal, 10 lbs of ground rock phosphate and 2 lbs of Muriate of Potash per 100 sq ft of garden surface applied in late fall. (Cottonseed meal is recommended because it has none of the seeds found in animal fertilizers.) Never add nitrogen after fruit has set. If your soil is prepared and fertilized properly, you should never need to add fertilizer but once per growing season. Also, because you are in the desert where both sun and wind exact a toll, use a ground cover to retain as much soil moisture as possible.

If your garden is plagued by coyotes and rabbits, fence it with a hardwarecloth buried 1 ft underground and purchase and distribute mothballs around the base of each plant. Regarding insects, surround your garden with a planting of marigolds, a plant most bugs don’t like.

Finally, for the serious gardener, purchase a soil fumigant and a large enough sheet of black plastic to hold that fumigant in the soil. Then, before you add your soil builders and fertilizers, fumigate the soil including a three-foot border around your planting bed, as described on the package label. When fumigation is completed, remove the plastic sheets, prepare the two feet deep garden bed by adding your soil builders and fertilizers, run your furrows, plant your seeds or seedlings and stand back and watch your plants grow to their hearts’ content.