Espostoa is a genus of 16 species of cacti known from the Andes of southern Ecuador and Peru. They usually live at an altitude between 2625 and 8200 feet (800 and 2500 m). The generic name honors Nicolas E. Esposto, a renowned botanist from Lima.
Espostoas are columnar cacti that mostly branch at the base to form a series of stems reminiscent of a big city skyline. The most notable feature of Espostoas is a presence in most species of dense white "hair," which quite dramatically covers the stems giving them a soft fuzzy appearance. However, this is just an illusion as underneath the soft hairs are numerous sharp spines arranged on many small ribs that circle the columns. In some species, the main central spine extends well past the hair making their threatening presence obvious.
Another trait of Espostoas seen in mature stems is the flower-bearing lateral cephalium, an area along the sides of the stems that produce especially dense wool and/or bristles out of which the flowers appear. These structures are brown, gray, or white and look as if something was smeared along one side of the stem. Fowers are cup or bell-shaped and typically 1 to 2 inches (2.5 to 5 cm) in diameter. They are mostly white or rarely reddish and nocturnal. Fruits are edible, sweet, and juicy.
Growing Conditions and General Care
Several species of Espostoa are especially popular in cultivation due to their fuzzy white hairy appearance. The plants are typically sold by large commercial growers as up to 12 inches (30 cm) long stems. However, these plants do not grow nearly as vigorously in pots as in the ground. Instead, plants quickly fill the pots, becoming pot bound, and then growth slows to a crawl. As a result, these plants rarely, if ever, reach maturity, meaning they do not produce the cephalium and, subsequently, do not flower. On the other hand, those in warmer climates that can plant the species directly in the ground may indeed have plants that form a nice grouping of stems that will eventually flower.
Like all cacti, Espostoas require a sunny location and well-drained soil. In summer, they appreciate fertilizer and wetter conditions. In winter, they need rest, but the temperature must not drop below 54 °F (12 °C).
They are appreciated for their decorative qualities due to their white fleece.
Espostoas can be successfully propagated by both cuttings and from seeds. The seeds are quite easy to germinate and grow. Their main requirements include high humidity levels, free-draining soil mix, and enough water, light, and nutrition.
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