I thought I would start out the summer growing period with a very interesting group of cacti found naturally only in Antofagasta, Coquimbo, and the Atacama desert on the coastlines of Northern and Central Chile, the copiapoas. They thrive near the coast on rocky or stony outcrops and are exposed to extremes of strong sunlight, scarce rainfall and howling winds which constantly dry them out. In order to protect themselves in this harsh climate, many copiapoas have developed outer coverings of thick, whitish wax layers which give them their typical chalky-blue-white appearance. It is this chalky coloration which many collectors worldwide prize in this genus. Unfortunately, copiapoas don’t begin to produce this white wax until they reach adulthood, which can take many years. As such, many adult and magnificent plants have been stripped from their natural habitats and sold to collectors worldwide. This has resulted in a serious depletion in the wild. What’s more, these habitat-collected, mature specimens are very difficult to rear in captivity. Most never re-establish and slowly die away. Even as seed-grown plants, these are still quite challenging plants to rear well, particularly in our hot, humid environment, although seed-grown plants have a much better chance of surviving and thriving in cultivation. I do enjoy challenges (or maybe I’m just a sucker for pain and agony…sometimes, I’m not so sure what the real case is) and have taken a fascination toward these Chileans. The plants are just now starting to put out new spines and are plumping up a bit. I expect them to be in full growth in about a month’s time.
The genus copiapoa contains over 25 species (depending on which botanist/taxonomist you follow). The name copiapoa comes from the city of Copiapó in northern Chile. These cacti have adapted to meeting their water needs from the fog that often blankets the coast, since it rarely rains in their natural environment. Some copiapoas are globular, some are columnar, some have brownish colored bodies, while others are blue-green. In the spring and summer, mostly yellow flowers are produced at the plant’s crown. These flowers are about one to two inches in diameter and are open-faced.
Copiapoas can be divided into two broad groups. The first group includes the larger, glaucous or white-waxed species (e.g., C. cinerea, C. gigantea, C. coquimbana). These are more difficult to grow well and flower in cultivation. In fact, these plants have to attain a fairly old age before these start to flower. The second group consists of the much easier to grow, smaller, brown-black species such as C. hypogaea, C. tenuissima and C. esmeraldana. Plants from this second group flower at a much younger age, some as early as two or three years old. I have only seen copiapoa flowers in this second group.
Copiapoas grow slowly in cultivation. C. cinerea and its variants are probably the most popular of the group because of their beautiful shapes, blue-green, chalky body coloration when the plants are older, and their very dark spines which provide a wonderful contrast to the white blue-green bodies. Unfortunately, it is one of the slowest growing of all cacti. While this species can reach a height and width of up to 4 feet, it takes up to 15 years to reach a height and width of only 4-1/2 inches. This globular shaped species is solitary at first; after many years, becoming slightly columnar and clustered. This species will produce a white, waxy coating after 5 to 10 years, though overhead watering will wash it away. C. tenuissima is an interesting species that will turn almost black in direct light. It can eventually grow into a 10-inch clump. This variety is covered in white down and black spines.
In cultivation, some copiapoas may change in appearance as compared to their natural growth habits. As examples, the color of some cultured species, notably C. cinerea and its variants, is often different, the beautiful chalky coating from some species which is the prized characteristic by most collectors sometimes fails to appear in cultured plants or is sometimes washed away. In addition, the spination of cultured plants is often weaker, and even the shape of the plants becomes more elongated. Copiapoas are propagated by seeds, grafting, or division if the species is a clump-former. The seeds are produced in very small quantities and grow slowly.
These cacti are excellent for growing on windowsills and greenhouses, as long as there is plenty of direct sunlight and air circulation. I’ve been growing most of my plants in a nice-sized dish garden. It is appealing to me to see the different species and forms together in one bowl, where differences in growth habit, spine and body coloration offer wonderful contrasts. Copiapoas need very well-drained, mineral-based soil that is moderately watered in the summer and kept fairly dry in the months from November through early March when the plants become dormant. In hot regions like Metro Manila, it is important that they have good ventilation, as they are easily burned. Copiapoas are a beautiful genus for the succulent connoisseur to grow. Someday, I do hope to get the chance to see these beauties in their native habitats in Chile. I also hear the country itself is quite fascinating and a must-see.