Echinocereus must be my favourite cactus genus, judging by the number of plants I have, and among them Echinocereus dasyacanthus is probably my favourite species, because of the wonderful range of flower colours. These are not the result of years of hybridisation and careful selection, but occur naturally! The species epithet dasyacanthus means ‘hairy spined’ although the spines are not actually soft, and I would describe the appearance as bristly.
Echinocereus dasyacanthus is known in the US as the Texas rainbow cactus or Texas rainbow hedgehog. Its distribution comprises New Mexico and Texas (particularly around Big Bend) in the USA, and Chihuahua and Coahuila in Mexico.
Echinocereus dasyacanthus is usually single-stemmed but can branch basally. The stems are up to 25cm tall and 5–10cm in diameter and usually have 15–18 ribs. The spines characteristics vary greatly. There are typically 3–12 central spines that are 0.5–2.5cm long and 12–25 radial spines that are 0.5–1.5cm long. The radial spines are interlaced and overlap each other, and mostly obscure the stem. The typical spine colours are tan to yellow to pinkish or brown.
The flowering season for E. dasyacanthus is from March to May in habitat, but tends to be May-June in the UK. The large flowers grow at the sides of the stem above the areoles close to the stem apex. They are most commonly yellow with a green throat, but they range from pale to dark yellow, orange or deep red to pink. The flowers are typically 8–12cm long and 7–14cm wide.
The fruits of E. dasyacanthus are usually green or greenish purple at first, and as they mature they become a darker purple. They are round, fleshy and quite large. The pulp is juicy and white to purplish-pink in colour. The spines on the fruit are deciduous.
Echinocereus dasyacanthus can be found on rocky, arid mountain slopes, the desert floor, and in desert grasslands. Depending on where a particular clone comes from, this species can be quite hardy – especially those originating from higher altitudes in the US, such as in the Big Bend area of south-west Texas. I bought almost all of my plants from Chiemgau-Kaktus (Michael Kiessling, Germany) and Kakteen Niess (Gerald Niess, Austria) before Brexit. I grow them in groups with other hardy cacti (mostly other echinocerei) in large ceramic pots which stay outside year-round. The substrate is a third John Innes No.2 and two thirds horticultural grit. I rarely water my outdoor cacti unless there is a prolonged drought, which does not happen often in Wales. In winter I move the pots to a balcony where an overhanging roof provides some rain protection.
During the ‘Beast from the East’ in early March 2018 all my outdoor cacti were covered in snow, but Echinocereus dasyacanthus was flowering happily three months later.
Text and photos by Frank Sengpiel
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