Ficus
Ficus
Over the years Plants for the Southwest/Living Stones Nursery has become known or our Sonoran Rock Figs. In the early 80’s Gene worked as plant propagator at the Arizona Sonora Desert Museum. While visiting Alamos, Sonora he saw beautiful, huge Ficus palmeri trees growing above the arroyos. Seeing the roots growing in and around the rocks on the banks of the arroyos he wanted to recreate that beauty once back in Tucson. Hence the birth of the Sonoran Rock Fig.
Pictured here you can see just one example of the Ficus mounted on a rock.
We love mounting figs on rocks and when we have plants available everyone in the nursery takes their turn at creating another Sonoran Rock Fig.
Care: Ficus petiolaris & Ficus palmeri ’Sonoran Rock Fig’
Ficus petiolaris/ F palmeri are members of the fig family (Moraceae) making them a close relative of the edible fig (Ficus carica) and mulberry (Morus alba). They are native to rocky canyons and cliff faces of the Sonoran desert from central to southern Baja, Sonora and several islands in the Gulf of California. F petiolaris/F palmeri naturally flower in winter and early spring, producing a fruit similar in appearance but much smaller than the edible fig. In nature these species can reach 20 to 30 feet in height, but when grown in a container, like most succulent plants, F petiolaris/F palmeri will restrict its growth to the pot size. This character, along with its ability to store water, makes the rock fig one of the best containerized patio plants used here in the arid southwest.
Light requirements
F petiolaris/F palmeri need the maximum amount of light available, up to and including full sun, during its growing season. Here in the southwest our growing season can safely be considered to extend from April through October. For the very best growth, these plants should be grown outdoors in filtered sunlight, like that under the canopy of a sparsely branched tree (mesquite), or near the edge of the canopy of a more densely benched tree (blue palo verde). If the specimen is in a 12” pot of larger, it may be grown in full sun.
At the end of the growing season, with the lowering of temperatures, rock figs will drop their leaves and become dormant for the winter. It is at this time that the plants should be brought indoors to protect them from freezing. They do not need much light when dormant but should not be put in total darkness. Preferably, a south or west window would be best, but any bright location in the home should suffice.
It is important to note that this plant must be returned to proper light conditions prior to its resuming growth in the spring. If it starts to leaf out and grow indoors, and this is possible all winter long if house temperatures are too high, these leaves will sunburn and probably drop off when put outside. However, if this does occur the plants usually recover quickly and simply re-leaf with sun adapted leaves. It is also possible to sunburn the stems if the plant is put out into full sunlight before it has leaves. This is more serious and can be avoided by easing it out into full sun, or taking steps to temporarily shade the stems in some way (e.g cut branches from any available shrub and lay against the stem for several days).
In some situations, rock figs can be grown indoors, but only in rooms that have a multitude of widows and a skylight with extremely bright light and good air movement. It is also recommended that the container be periodically rotated to prevent one sided growth. If grown indoors, the plant probably won’t go dormant in the fall unless water is withheld.
Watering
Like all succulent plants, rock figs have the ability to store water. In their native habitat they live and grow with only the available rainfall, storing water in wet times to sustain them through drought. In extreme drought, even during the growing season, they can drop their leaves and become ‘drought dormant’, only to re-leaf with the first available moisture. These arid conditions do not adversely affect the plants, but only cause them to grow slowly. This is a character to be taken advantage of in cultivation. F petiolaris/F palmeri can be left for several weeks to several months (depending on the size of the plant and the pot and the length of time in that pot)without being watered and only suffer a setback in growth, but not adversely affecting the health of the plant. However, it is extremely important to realize that a container grown plant has its entire root mass confined to the pot, and unlike a plant in the ground that can actually grow roots in search of available soil moisture, is dependent on an outside source of water to survive and grow.
At the other extreme is the nurseryman who maintains a watering schedule to keep the root zone constantly moist so as to not lose any precious growing time or energy. The plant might be watered as often as several times a week or even every day, depending on factors such as light, temperature, humidity and soil mix.
Rock figs, like most desert plants, respond to water and can grow many times faster in cultivation than in the wild, providing optimum conditions are maintained.
Somewhere in between the harshness of nature and the pampering of the nursery is the home growing situation. For general good growth and overall healthy appearance it is recommended to water regularly and to let the soil dry out in between waterings. The best way to decide when to water is to check the soil, with your finger, at about one inch depth. If it is dry, water; if it is not, wait until it is dry. There are several factors that will influence the timing here. Light plays a major role in determining how much water a plant uses. The more light a plant receives, the more water it needs. Related to light is temperature. Up to a point, the higher the temperature, the greater the water use. Although, in extremely high temperatures some species of plants will actually slow down functions in an effort to conserve water. It is at these higher temperatures that some containerized succulents are prone to rot if the soil moisture is too high. Rock figs are very heat tolerant and usually do not have this problem. Another factor in determining water requirements of a plant is air movement. Most plants do best with good air circulation, but not a continual wind. The more air movement, the greater the water use. The length of time a plant has been in a specific size pot will also affect watering. As a plant grows in a given pot, it displaces soil with root mass. Since water is held in the potting soil, the less soil there is the, less water available to the roots. Once the soil moisture is depleted, succulents begin to use stored moisture. If this condition persists, the plant will cease active growth. As a rule of thumb, if a rock fig is potted in a well drained soil mix and is in a proper size pot and under adequate light conditions, it should be watered anywhere from three times a week (6-inch pot) to every two weeks (20-inch or larger pot) during the peak of the growing season, and tapering at both ends of the growing season. During the winter a rock fig requires only a minimum amount of water to maintain it through dormancy. This is variable also, but for a dormant plant watering will be from twice a month (6-inch pot) to possibly once every six weeks (20-inch or larger pot), again, depending on the ambient conditions. For all pot sizes regular watering should not be resumed until temperatures warm and the plant starts to show signs of growth. This is normally the beginning of April.
Any watering of a plant should provide a thorough drenching of the soil, with some amount of water draining through the pot, so as to wet the entire soil mass and to prevent salt buildup.
Fertilizing
Under natural conditions plants utilize nutrients in the soil they grow in and continually grow roots to ‘fresh’ soil. In a container a plant can use up the available nutrients in a relatively short time. When these nutrients are depleted, growth slows and in the extreme will stop or become distorted. Also, nutrients are leached out of the soil with watering. Under ideal conditions (usually only achieved in the nursery) rock figs can be fertilized with what amounts to a full strength application of a general purpose fertilizer every two weeks. Under most home conditions, and only if the plant is healthy and growing, a half strength application once a month during the growing season (April-October) of any available house plant food will be adequate.
Temperature
In their native desert home, rock figs are not subject to freezing temperatures. Here in the Southwestern US we regularly experience sub-freezing temperatures. (Tucson averages twelve nights below 32°F) This is a major consideration in growing F petiolaris/F palmeri. They must not be allowed to freeze! Most often this is simply a matter of moving the container to a protected location. It is desirable that the plant have good light through the winter, such as that available through a sliding glass door, just inside the house from the patio. The further into the house the plant is, the less light available. When overintejed inside, rock figs should be allowed to go dormant. If home nighttime temperatures stay above 55°F, dormancy may need to be forced by withholding water until the leaves drop. If indoor night temperatures are too high (70°F+) the plant may be induced to grow. This is an undesirable situation causing weak, etiolated (thin, light seeking) growth and an alternative overwintering area should be found. If a plant does experience this type of growth, it should be pruned off after being moved outdoors in the spring.
Rock figs can be overwintered outdoors if kept in places that are absolutely frost free and dry. Night temperatures vary around Tucson (and Phoenix) but generally most homes have a frost free area outside against a wall, under cover of a solid roof, and even better, on the south side of the home, under a roof. Under any circumstances, rock figs should be kept very dry (see section on watering) at temperatures under 50°F. If outside temperatures are expected to reach the mid twenties, even plants under a roof should be moved or covered. The best covering consists of at least two layers with the outer one being plastic and the inner one some type of woven fabric, simply draped (or suspended) over the plant. When considering low winter temperatures, it is important to understand your home’s specific conditions. Sites around town can vary by ten degrees or more and locations outside the house are equally variable. If you are unsure of outside low temperatures it would be safest to overwinter the plant indoors.
When a rock fig is subjected to freezing, the stems will die back to greater and greater diameter with increasing lower temperatures. If the stems are frozen, they should be pruned back to that point, before or just after growth resumes in the spring.
Growth and flowering
Ficus petiolaris/F palmeri are naturally slow growers. A great deal of this slowness can be attributed to minimal water. But it is this very lack of water that makes for some of the most interesting growth forms in the species. In cultivation a balance can be achieve that will promote faster growth and maintain a desirable ‘natural bonsai’ character. In the nursery under ideal conditions, the fastest growth rate is usually achieved. Under most home conditions something less should be expected. But fast growth, or in some cases any growth at all, is not necessarily desired. Specimen size plants or those in decorative containers are usually desirable to keep in their present situation for long periods of time. For these, watering and fertilizing should be kept at a minimum, letting the soil stay dry longer and fertilizing only once every two months (or less) during the growing season.
Rock figs rarely flower in cultivation. This is a factor of size as well as age. In their native habitat in Sonora and Baja they can be expected to flower in late winter and early spring with the fruits ripening shortly thereafter. Like all Ficus species, the flowers are inside of what we recognize as the ’fig’. They are pollinated by a tiny wasp in the process of laying its eggs. A mature fruit of Ficus petiolaris/F palmeri is about the size of a nickel. These have traditionally been eaten by the native Indian population. A mature fruit will contain up to several hundred seeds, some of which are eaten by the larve of the pollinating wasp.
Soil and Potting Up
The basic characteristic of potting soil for Ficus periolaris/F palmeri is that it be well drained. This means that water should drain through the soil in a matter of seconds after being applied. A good commercial cactus mix with the addition of an equal part of pumice or clean, small gravel will work well. There are many recipes for soil and every grower uses a different one. It is a good idea to find one that you and your plants like and stick with it as your cultural habits (watering and fertilizing) are somewhat dependent on the soil mix used.
Rock figs will tolerate being pot bound without ill affects. When repotting is needed it should only be done during the growing season and the not late in the season. The process is usually a simple matter of removing the old pot and putting the plant, with its rootball intact, into the larger pot and filling in with the soil mix making sure to keep the original soil level in the new pot. Removing the old pot can sometimes be a problem and occasionally a hammer may be needed to break apart the old pot. Unlike other succulent plants, rock figs can be watered immediately after repotting.
Diseases and Pests
In cultivation Ficus petiolaris/F palmeri are rarely subject to diseases, but are occasionally host to one of three insect pests. Mealy bugs, scale insects and sider mites can all inflict damage on these plants. Although usually not serious, these pests can cause distorted growth and sap the vigor from a healthy plant. Outdoor growing in most cases will prevent these problems, but occasionally an infestation will occur. For spider mites a jet of water aimed to physically displace the pests will often times suffice. This treatment may need to be repeated for complete control. If the mealy bugs are not overwhelming, a cotton swab dipped in alcohol will kill all of them it touches. This should also be repeated for several days. Scale insects can be scraped off of the plant with a fingernail, repeating until there is no recurrence of them. There are numerous commercial preparations available for these insects, but it is best to avoid their use if possible, since some of the chemicals themselves are injurious to rock figs.