Vatricania guentheri

Vatricania guentheri is a very decorative candle cactus that forms erect branches 10 cm (4in) wide and 2 m (7ft) tall, covered with a prickly down of short, dense, golden hairs. Initially columnar, it then develops a more bushy habit. Over time, curious brownish-red tufts of hair appear, from which several dozen large cream-yellow nocturnal flowers emerge in summer. It is not very hardy so best grown in a pot on a veranda or in a rockery or dry bed in frost-free gardens. Grow it in full sun in fertile, well-drained, sandy or rocky soil.

Native to mountain slopes and valleys in the eastern Andes of Bolivia, at altitudes between 800 and 1300 m (2625 and 4265ft), Vatricania guentheri is well adapted to arid conditions. It belongs to the cactus family and can be found in dry and hot mountain slope forests along with other cacti. In less arid regions, it mixes with more lush, shrubby, and treelike vegetation. It thrives in full sun in fertile, well-drained soils mixed with sand and gravel, and should never be watered; it tolerates cool temperatures better than other cacti. In pots, use a special cactus soil or a mix of potting soil and garden soil. This species can withstand short freezes down to -6°C (21.2°F) once mature.

Vatricania guentheri, also known as Espostoa guentheri, is a perennial plant that begins as a candle cactus when young, initially developing a single pale green branch or "trunk". Its branches are about 10 cm (4in) in diameter with some distinct ribs (up to 27) punctuated by areoles that bear 25 short, thin, dense spines, 5 to 15 mm (0 to 1in) long, forming a beautiful golden down that shines when backlit. Its initially columnar habit becomes bushier with the development of several branches (up to 15) at its base. These branches will then bear curious tufts of very dense intense reddish-brown hair, about 5 cm (2in) long. It grows slowly and reaches 2 m (7ft) in all directions. In summer, under good growing conditions, flower buds form within these hair clusters and open into cream-yellow trumpet-shaped flowers, 8 cm (3in) long and 3 to 5 cm (1 to 2in) wide, at night.

In mild climates, Vatricania guentheri can be planted in a large rockery, a dry slope, or a raised bed enriched with gravel or coarse sand. It can be grown with hardy prickly pears like O. humifusa Millevaches, tall ferula, fairly hardy candle cacti (Cleistocactus strausii, Cylindropuntia imbricata), and ground-covering plants like dwarf artemisias, Rhodanthemum, Ajania pacifia, all of which are equally undemanding. Gardeners in colder regions can grow it in a very large pot on the terrace, carefully choosing the most sheltered spot and ensuring it receives full sun. This tender plant should be overwintered in a very bright, well-ventilated room in more humid and colder regions.