Synonyms:

Arrojadoa penicillata var. decumbens
Cephalocereus penicillatus
Cereus penicillatus

Habitat:

Arrojadoa penicillata, native to southwestern Pernambuco, northern and eastern Bahia in the east of Chapada Diamantina, and the Rio Jequitinhonha valley in the northeastern part of Minas Gerais, Brazil, thrives at elevations ranging from 200 to 850 meters above sea level.
This species is well adapted to various habitats, including granite and gneiss inselbergs, lajedos, sandy dunes, and stony ground (with occasional occurrences in limestone areas). It typically grows under or amidst shrubs within the caatinga-agreste and caatinga-campo rupestre (dry brush and other thorny vegetation) environments. Arrojadoa penicillata demonstrates widespread and common distribution across its range.
Unfortunately, the natural habitat of this plant is facing degradation due to a range of human activities, including deforestation for logging, agricultural expansion, cattle ranching, urban development, quarrying, and fires. These factors pose significant threats to its continued well-being in the wild.

Description:

Arrojadoa penicillata is a bushy cactus that often grows up to 2 meters tall. It may lean on surrounding plants or sprawl on the ground, especially in sandy areas. It produces bright crimson flowers at the growing tips of its stems. These flowers are about 4 cm long. The stems are slender and usually less than 10 mm thick, except near the flowering tips where they can be a bit wider. The cactus has about 10 low ridges with closely spaced areoles (small cushion-like structures) that bear short, outward-spreading spines.
Maintaining this cactus can be a bit challenging, but it’s quite interesting to grow. Its name, “penicillata,” comes from the Latin word for “shaped like a brush.”
The stems of Arrojadoa penicillata are segmented, not very fleshy, and typically olive-green in color. They are very slender, reaching lengths of up to 2 to 4 meters, with a diameter of 1 to 1.8 cm. Near the flowering tips (called cephalia), they can expand to 2.5 to 3 cm in diameter. The cactus has a woody vascular cylinder, and its rootstock is fibrous, without tubers or rhizomes.
It bears 10 to 12 low ribs along its stem, with small, closely spaced areoles that initially have long hairs that eventually fall off. The cactus sports (1 to) 2 to 3 (to 4) central spines that are reddish-brown, stout, and rigid, measuring 4 to 30 mm long. Additionally, it has (6 to) 8 to 10 (to 12) radial spines that are short, about 3 to 5 mm long, and very fine, lying flat against the surface.
The cephalia, which form at the top of the stems after each season’s growth, consist of 3 or 4 ring-like clusters of white wool and long red to brown bristles, each cluster measuring 20 to 30 mm long. Once the flowering phase begins, the flower buds emerge from the cephalium.
The cactus produces flowers in clusters of 6 to 12, which open during the day and are pollinated by birds. The blossoms are pinkish magenta or reddish pink, measuring up to 3 cm long and 2 cm in diameter. The fruit is globose to obovate, sometimes laterally compressed, and can be greenish, dull red, olive-brownish, or whitish. It is about 12 to 25 cm long and roughly 12 mm in diameter. The seeds are dull black and about 1.2 mm in size.

Cultivation:

Arrojadoa penicillata can be a bit challenging to grow and is not recommended for beginners. Their serpent-like growth makes them ideal candidates for hanging baskets.
They tend to grow relatively quickly under the right conditions. They require a rich but very porous mineral cactus mix soil. Repotting can be tricky, as their root systems are weak and they may take a while to re-establish. It’s important to use a pot with good drainage.
They thrive in very bright light, although not as much as the most arid cacti. In strong light, they may take on a bronze hue, which can encourage flowering and heavy spine production.
These cacti grow from April to October and can’t tolerate long periods of total dryness. However, too much water can lead to rot, as their weak root systems may struggle to absorb water from wet soil. Due to their tropical origins, they do need a fair amount of water, but it’s essential to let the soil dry quite a bit before watering again.
Avoid feeding them in winter. While they rest from October to April, they can’t withstand cold or even fairly cool temperatures. It’s crucial to keep them above 8-12°C at all times, as severe damage or death can occur at temperatures that most cacti wouldn’t mind. They may also need more frequent watering in winter compared to other cacti, approximately once a month (but they can withstand short periods down to 4°C).
In terms of pests and diseases, they may be attractive to various insects, but healthy plants grown in a mineral potting mix with good exposure and ventilation should be nearly pest-free. However, watch out for red spiders, mealy bugs, and scales, which can occasionally pose a problem. Rot is only a minor issue if the plants are watered and ventilated correctly. Fungicides may not be very effective if these conditions aren’t met.

Propagation:

The propagation of Arrojadoa penicillata can be carried out through seeds and cuttings, obtained by its offsets.

Curiosity:

The species name comes from the Latin word “penicillatus” which means “shaped like a brush”.

Official Web Site:
www.giromagi.com

Italian Blog:
www.giromagicactus.com

Tips:
Read our advice