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Exotic Beauty: Unlike most cacti, the orchid cactus is a rain-forest native and lives as an epiphyte, growing on the limbs of trees. It is similar to many cacti, however, in its bright, showy blossoms.
Photograph courtesy of Mary Bartholomew
New soil and old soil should be mixed in the proper way
By Tony Tomeo
I would not enjoy house plants if it weren't for my colleague Brent Green. He has sent me many tropical plant species from Southern California over the past 11 years, since we graduated from college and relocated 200 miles in opposite directions. Some of the species he is able to grow in his garden do not tolerate the winter weather of the Santa Clara Valley. Because some have lived in containers for nearly that long, the soil has "collapsed" as it has decomposed.
When soil level becomes so low within a container that more must be added, it is usually not advisable to add new soil above older soil. Instead, the container should be "stuffed". This involves removing the entire plant and root system from the container, adding fresh soil, then replacing the plant on top of the fresh soil. If the container is tapered, additional soil will be necessary around the root system as well. The quantity of fresh soil added should be sufficient to raise the root system to the desired depth in the container.
During this procedure, any loose soil on the bottom of the root system that has become too dense and water-soaked for healthy root growth may be removed. A small amount of fresh soil may be added on top to cover any exposed roots and to level the top surface. Soil added on top should not be deep enough to cover the bases of stems, which might easily rot if buried. Many plant species, however, that grow from rhizomes do not mind considerably more soil added to the surface.
Stuffing is performed for several reasons, but mainly because roots grow down more than they grow up. It is also done so that much of the decomposed material in the older soil leaches down into the new soil. This enhances the quality of the older soil without totally ruining the fresh soil.
Please note that I had difficulty with my email and was not able to respond to all correspondence. I apologize to those who received no response and suggest you try to contact me again at LGHORTICULTURE@aol.com, or at 408.358.2574. I try to respond to telephone messages while in the office on Mondays and Tuesdays.
Flower of the Week: Orchid cactus
Of all the exotic plant species I have encountered, the various hybrids of Epiphyllum, known as orchid cactus, are among the most unusual. Most garden enthusiasts are familiar with various species of cacti that prefer direct sun exposure and minimal irrigation, just as they would receive in their native desert habitat. However, orchid cacti are not normal cacti.
They are native to tropical rain forests of Mexico, Central America and South America. They are also epiphytic, growing on limbs of larger trees. Consequently, they prefer conditions similar to those preferred by epiphytic bromeliads and orchids. Sun exposure should be filtered, and soil must be very well drained and aerated. Many orchid cactus enthusiasts mix their own soil medium to include coarse bark and foliar debris.
Collecting orchid cacti was very popular from the Victorian period until about the 1950s. Since then, other species, such as orchids, roses and rhododendrons, have become more popular among collectors. Consequently, the more exotic hybrids of the orchid cactus are available from only a few nurseries and from other collectors.
As with many varieties of plants that have been in cultivation for a very long time, orchid cacti are often found in older gardens, where someone once grew a few plants. Some garden enthusiasts acquire them when moving into a new older home, without knowing what they are.
It is uncertain how orchid cacti were developed from the various species of Epiphyllum. More than 10,000 cultivars are currently registered with the Epiphyllum Society Association. No one knows how many more rare cultivars are not registered.
The foliage of most orchid cacti is not remarkable. It is succulent, flattened and usually pendulous. Stem segments range in size from only 2 inches to 2 feet or more. However, the blooms are very impressive. Those with smaller flowers may produce as many as 50 blooms in one phase. Those with larger flowers may produce as few as one flower, but as many as 20. Some of the largest flowers may be 10 to 14 inches long! Color range includes just about every color, except for blue.
Mary Bartholomew, a representative of the San Francisco Epiphyllum Society and the supplier of this week's photo, may be contacted at mbartholomew@pobox.com for more information about Epiphyllum.
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Willow Glen, California Since 1992
