Synonyms:

Although there has been much confusion in attaching the name Cereus forbesii to this plant, it still has only one synonym:

Piptanthocereus forbesii

Habitat:

Cereus forbesii f. variegated occurs usually in nurseries: variegated forms are very rare to find in nature. The regular Cereus forbesii, instead, is native to an area that stretches between various provinces of Argentina, Bolivia and Paraguay, where it is largely widespread and not threatened with extinction at all. It grows in diverse habitats such as rocky outcrops in hills, forests, on the border areas of salt flats, and in arid plains, at an elevation range between 500 and 2000 meters above the sea level. It frequently occurs together with plants of specific species such as Stetsonia coryne and Opuntia quimilo.

Description:

Cereus forbesii, in its natural habitat, take the shape of a big, tree-like shrub, with a main, cylindical stem, brownish in colour and spineless, branching at around 1-1.5 meters of height. Branches grow dichotomously: this means that the angle between two of them is always 90º. This feature earns to Cereus forbesii its typical triangular shape. Young branches, though, loose their cylindical shape and their brownish colour, being divided into usually 4, deep ribs and showing a bluish-green tinge. In cultivated plants, we usually see the ribbed, bluish stems instead of the older, brownish ones. The areoles, which are the typical buds of cacti that are able to form spines, are yellowish-white, small, slightly woolly, and form 4 to 8 spines each. The spines are divided into radial ones, which are shorter, yellowish-brown, and point in all directions, and central ones, pointing outwards, longer (around four centimeters), more thick and stout, as well as darker in colour.
Flowers are solitary and sprout on the sides of the stems, from the crest of the ribs. They are flashy, white or reddish, up to 20 centimeters long and 10 centimeters wide. After withering, they are replaced by fleshy, red fruits, equipped with a bluish pruine. The variegated form of Cereus forbesii share all the above mentioned features with one main difference: the colour of the stem. In variegated forms, still unclear genetic mutations cause the inability of some regions of the stem to produce chlorophyll. This results in bright yellow areas, irregularly scattered along all the plant. The variegated forms, thus, end up to be coloured in green and yellow. The distribution of the yellow areas on the plant depends on the individual: it is unique for every specimen. That’s the reason why the variegated forms are so sought after by succulent collectors.

Cultivation:

Cereus forbesii f. variegated is not particularly difficult to grow. Here below are our tips:

Exposure to sunlight should be partial when the plant is young and full when it reaches adulthood.
Cereus forbesii f. variegated is frost-sensitive: its mimimum tolerate temperature is deemed to be -2ºC. We advise though to keep it at temperatures above 10ºC and to move it indoors in winter to avoid frost damages.
The substrate should be well-drained: a specific substrate for cacti is the most recommended.
During the summer, water it once every 3-4 days, paying attention to water stagnation. In Autumn, reduce the watering frequency until completely suspending any irrigation in winter.
Fertilization can be done once a year during the growth season, using a specific product for succulents, rich in Phosphorus and Potassium and poor in Nitrogen.
Cereus forbesii f. variegated is a rapid grower: replant it every year and anytime the plant outgrows its pot.

Propagation:

We suggest to carry out the propagation of this variegated form agamically: it’s more likely that the it is more likely that the seedlings thus propagated will also develop variegation in color. In Spring, you can obtain cuttings from parts of the stems and replant them in a fresh cacti mix after the wound has dried up properly.

Curiosity:

Cereus forbesii has risen up some confusion among botanists: Cereus validus, Cereus uruguayanus and Cereus pachyrhizus are only a few of the names with which this species has already been called.

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