Sandhills Orchid Society

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Sandhills Orchid Society Speaker’s Note 

An Overview of Bifoliate Cattleyas – Linda Thorne

Jan. 11, 2022 Submitted by Joy Lemieux: 

Focusing on the best known bifoliate cattleyas, Linda presented an informative overview of the ten of the best known, and most frequently grown species. These plants are the foundation of many of the hybrids available today. A basic understanding of their characteristics is helpful in understanding how to grow our collections well. Linda also included many stunning photos of these stunning plants. The fact that many of the photos were of her own awarded plants was certainly a bonus.

Bifoliates carry two leaves at the top of the pseudobulb. They are found in a band on either side of the equator through South America, Central America and through the Caribbean. They are therefore warm growing and do best with daytime temperatures that range from the seventies to the mid-nineties. Nighttime temperatures are more problematic. Most prefer to remain in the high 50 and low 60s range, but more and more growers are pushing that downwards and finding that the plants continue to bloom. With reduced nighttime temperatures however, one runs the risk of fungal infections. It becomes a balancing act, with higher fuel prices playing a significant role when one considers the costs of heating a greenhouse or a sunroom. Additionally, areas where Bifoliates originate differ markedly in the levels of humidity available, but most prefer a moderately humid environment.

Linda began with C. aclandiai, which she described as a smaller plant, when compared to many of the others in this group. I have seen the pseudobulbs described as “stubby” which I suppose qualifies it as a “mini”. It was initially described in 1840 and is identifiable by its small lateral lobes that do not completely enclose the column. It is characterized by spotting on both the flowers and the foliage. It generally carries one to two flowers at the apex of the pseudobulb. The blooms are fragrant and long lasting, as in three to four weeks. Linda considers it hard to grow.

C amethystoglossa can be forty inches high, making it one of the largest Cattleyas. Mature plants can be very floriferous with up to thirty flowers, but most plants produce only six to eight. The flowers can be four inches across. It requires high temperatures as well as high light, as well as ample water while in growth mode. But it also needs a definite rest following flowering. It is native to the Baha peninsula and northern Brazil, growing on rocky outcrops or on palm trees in full sun. It grows best in an open mix in a clay pot or in a basket where the mix dries quickly between waterings. When shopping for this plant, look for a form with well-spaced flowers as they tend to crowd up on the stem and do not present well.

C aurantica is fun to collect with its multiple color forms, which range from yellow to orange to red. Some forms even have some red or purple striations in the throats. The flowers are smallish, only one and a half to two inches across but bloom in tightly packed clusters. In its

native environment it grows on exposed rocks or on trees, and is tolerant of temperature variations. C aurantiaca tends to self-pollinate because the flowers are held tightly together. Blooms last three to four weeks but may collapse sooner if they cross pollinate.

C bicolor is another tall plant, with pseudobulbs up to thirty inches high. The foliage is also large, with leaves as long as six inches. It typically blooms with three to ten flowers that measure three to four inches across. There are several color forms ranging from pale green to olive to a coppery brown. The lip is strongly contrasted in color and can be crimson purple to pale rose. The lip has no side-lobes to encase the column, an identifying characteristic that is genetically dormant. It needs ample water when in growth mode but also a definite dormancy after blooming. In nature it grows into large clumps on rocks as well as in tall treetops in central Brazil.

C bowringiana is a strong, easy growing plant that is typically about twenty-four inches high. The foliage is thick and often crowded on the plant. Blooms are two to three inches across, and a well bloomed plant can carry as many as thirty flowers on multiple stems, generally with five per spike. Flowers are generally rose-purple, often with a glistening, satiny texture. The lip is often a slightly darker purple. Young plants may carry only one or two blooms, but flower count increases with the plant’s maturity so it is worth the grower’s persistence. C bowringiana is known as a good beginner’s plant as it is temperature, light and even limited humidity tolerant. In nature, the plants grow on rocky cliffs by streams that provide much needed moisture. It is native to Belize and Guatemala.

C forbesii is another Brazilian native that is noted for being a strong, easy grower that makes it a good beginner’s plant. Some have noted that it is the least beautiful of the genus as the color forms are often washed out or dull. I love it however as it blooms repeatedly, often surprising me with a second flush of blooms just when I think it’s done for the season. The pseudobulbs are thin and often twist around, forming a tangled mess in a basket. I find this appealing as it obviously grows like this in nature. The thin pseudobulbs are indicative of the fact that the plant cannot tolerate drying out. I’ve never seen more than one flower at any time on a stem, but my plants often produce a fast-forming secondary flower after the initial flower has faded. One day there will be a faded flower, the next a ready to open new bud! Flowers range from a pale, washed out yellow-green to a muddy tan, but the smallish lip is pale pink with a bright yellow throat. Often there are red striations on the inner lobes of the lip. It thrives in a hot, humid environment that is often modified by softening sea breezes.

C granulosa is free growing, with slender jointed stems that can be up to twenty inches tall. The foliage is often six inches long. It carries five to eight flowers that measure three to four inches across. The sepals and petals are olive-green with small red spots. The lip is distinctive and often dramatic! It is white with a orange-yellow patch at the base as well as red spotting throughout. C granulosa is native to Brazil and grows in areas of rolling hills with swampy areas near the ocean. It is therefore heat tolerant and thrives when temperatures range from 70 to

90 degrees. In its native environment, there are minimal seasonal changes, making it ideally suited to cultivation in the typical North American home with temperature controls.

C guttata can range in height from twenty-four to forty inches high. It produces five to ten, fleshy flowers with heavy substance. The flowers generally measure two to three inches across. Flowers are yellow green with deep purple spots. The lip is white with a purple front edge. This is a warm growing species that can grow in seemingly nutritionally starved environments such as sand. It is specific about minimal temperatures and cannot tolerate temperatures less than fifty-five degree at night during its dormancy period. It is native to the Rio de Janeiro area in Brazil. The actual identification of this species has been somewhat controversial as some taxonomists have suggested that it forms the basis of a natural hybrid for several other species.

C intermedia plants are about fifteen inches tall, with six-inch leaves. In Brazil, there are fifty recognized color forms, but a rosy pink appears to be most common. Other colors range from purple to white. Several forms have amethyst-purple spots, mimicking the amethyst-purple lip. This has been the basis of most modern splash-petal while breeding the white form has been basic to modern development of pure white, cluster-flowered hybrids with no yellow in the throat. Plants typically carry two to five very fragrant flowers up to four inches across. It is widely distributed across Brazil. Linda described it as a “forgiving” plant, indicating it is easy to grow.

C schilleriana is considered a semi-dwarf plant with tough, red-spotted leaves. The flowers are noted for their heavy substance. They are three to four inches across, and typically have no more than two flowers per stem. Colors are variable, ranging from olive-green with brown and red-brown spots to deep rose-mahogany. The lip is typically yellow with purple stripes. The plants grow best mounted or in baskets with high light, strong air movement and excellent drainage. It typically grows in hardwood thickets on cliff faces with seepage from nearby rocks and streams. The environment is typically dry during the winter months followed by heavy rains. The plant typically blooms in spring with highly humid conditions. The plant is then subjected to extreme heat for the remainder of the year.

C violacea is considered by many to be very difficult Cattleya to grow. Carl Withner, a notable expert on Cattleyas refers to C violacea as “a deliberate growing species with specific cultural requirements”. Despite this, it has the widest distribution in nature of all the Catts. Typically, it grows on tree trunks along rivers in hot, steamy jungle conditions. Therefore, it is often found in the Amazon Basin, known for constant heat and high humidity. The plant is only ten to twelve inches tall, with two rounded leaves on each growth. The roots are thick and coarse, so they prefer to be grown mounted or in baskets that provide excellent drainage. The plant has three to five heavily textured flowers that are up to five inches across. Typically, they are bright rose-purple with a crimson-purple lip.

C walkeriana grows off stout rhizomes with bulb-like pseudobulbs that are only six inches high with one or two leaves that are only two to four inches long. The flowers are about four inches

across and typically rosy-purple to pink-lilac. The lip is generally a richer form of the same color but often has a white or pale-yellow base. The plant is extremely fragrant. Blooming can occur at any time of the year though they tend to peak in early spring and late fall. Flowers develop from small specialized shoots that are one to two inches tall and emerge from the rhizome near the base of the previous growth. C walkeriana is very popular in Brazil as it is free flowering and is able to withstand rigorous climatic conditions with little or no care. They thrive on limestone cliffs along rivers. In the wild they dry quickly after rainstorms, a requirement that must be met in cultivation for the plants to survive. Due to its widespread distribution over southern Brazil it is believed to have produced the natural hybrid C nobilior. Genetically it is dominant for its small size and its fragrance. It has been used extensively in breeding, but a tremendous amount of effort has also gone into selectively developing expanded color forms of C walkeriana itself. There are now pure albas and cerulean forms available. As is true with so many Orchids, the hybrids are often much easier to grown but may exhibit the same form and color appeal of the parent plant.

Linda closed her presentation with a brief discussion of repotting. She cautioned repotting Bifoliates at random times and noted that plants can be set back or even killed if repotted at the wrong time. The optimal time to repot is only as new roots are emerging, and before the new roots exceed two inches in length. If left until the roots are longer, there is a high likelihood that the roots tips will break off. Once damaged, these roots never recover, and serious damage is done to the over all health of the plant. Bifoliates are extremely sensitive! If repotting is attempted at any other time, plants tend to “sulk”. They fail to produce new seasonal growth, can miss a year of growth entirely, and/or they refuse to flower for several seasons. They have also been known to simply die. Linda also stressed that roots should be disturbed as little as possible. Once a plant outgrows its pot it is often sufficient to slip the old pot into a larger pot, pack the outer layer with loose mix, and allow the roots to grow out of the old medium into the new.​