Synonyms:

The name “Lemaireocereus pruinosus” is actually a synonym of “Stenocereus pruinosus”. Other synonyms are:

Cereus edulis
Cereus pruinosus
Echinocactus pruinosus
Rathbunia pruinosa
Ritterocereus pruinosus

Habitat:

Lemaireocereus pruinosus is native to Mexico, where it’s widely spread and not threatened with extinction at all.
In particular, it can be found in the provinces of Puebla, Veracruz and Oaxaca, where it grows at a very wide
altitude range (between 800 and 1900 meters above the sea level). Its great abundance is also due to the fact that it is cultivated for its edible fruits. Its natural habitat, instead, are deciduous forests and thorny scrubs, in semi-arid and hot climates (annual rainfall between 300 to 800 millimeters).

Description:

This columnar cactus is traditionally known in Mexico as “Pitayo de Octubre”, because October is the month when its fruits ripen, traditionally eaten by the people of that area. As other Lemaireocereus, it tends to branch from the base, though young plants are usually unbranched. Branches are usually upright and pointing upwards, forming a typical V-shaped/candelabra-shaped structure. The colour of its stem is greyish-greenish blue, and, in its natural habitat, it reaches a height of over 5 meters. The species name “pruinosus” is due to the white, waxy pruine that covers all its stem, that has a protective function from sun rays and reduces water losses. It has also the function to protect the plant from insects and pathogens. The stem is divided into 5-6, more rarely 9-10, ribs, very deep and pronounced and notched, with the areoles laying at the top of the notches. We remind, as always, that the areoles are the typical buds of the family Cactaceae, from which spines are formed. In this species, areola are small and brownish, spaced at around 3-4 centimeters from one another. Flowering one are larger and felted. Spines, instead, are short and arranged in radial ones, pointing laterally in all directions, 5 to 8 in number, brown in colour, of about 2-3 centimeters in length, and in central ones, which are 1 to 4 in number, grey to brownish in colour, 2-3 centimeters long. Flowers, instead, are much longer: up to 9 centimeters and 7 in width. They sprout from late February to May and once again in September, at the top of the stem. They stay open 24 hours a day, and are thus able to exploit many species of pollinators, both nocturnal and diurnal. Flowerrs have a highly decorative potential: they are funnel-shaped, white to pale pink, with crowded petals. After withering, they are replaced by ovoid fruits, sized like a small apple, 5 to 8 centimeters long and coloured in yellow, orange, green to purple. They are edible and are traditionally consumed by local populations. Seeds are very small (2.5 millimeters) and black.

Cultivation:

L. pruinosus is not particularly difficult to grow. Here below are our cultivation tips:

The required exposure is very bright, possibly with direct sunlight. There’s some different, though, according to the position chosen: if you place it indoors, we suggest to provide it with indirect light, while, if it stays outside, it will need bright, direct light.
A good ventilation is also important.
Lemaireocereus are suited for very hot climates. We advise to keep them at temperatures above 10-12°C. L. pruinosus, also, is particularly sensitive to cold. By the way, if you place it in a bright spot, under direct sunlight, and keep its substrate completely dry in Winter, it can resist down to -2ºC. We advise, in short, to plant it outdoors only if you live in areas with winters that are not too harsh. Otherwise, we suggest putting it in a pot and keeping it indoors during the cold season.
Water every 3-4 days from March to September, then stop watering completely during the vegetative rest. Do not water again unless the soil has dried up completely.
Use a standard compost for cacti and a neutral, light and very draining soil. A standard compost for cacti will do well.
Fertilize about once a month during spring and summer with a specific product for cacti, rich in Potassium and poor in Nitrogen.
L. pruinosus grows quite fast and you will need to repot it every 1-2 years. Choose deep pots which can easily contain the roots, better if made of clay or anyway of a material that enhance the drainage.

Propagation:

Lemaireocereus are usually propagated by seed or, more rarely, by cutting: suckers (when present) can be used as cuttings. Branches are usually scarce and therefore branch cutting is not recommended. Seeds are easy to germinate. They take 7 to 14 days to give birth to new plants, if kept at 21-27ºC in a moist soil. We suggest to cover them with a glass or plastic cover to be removed graduallly as the plantlets grow. In the particular case of L. pruinosus, branches are usually present and thus can be used as cuttings. After detaching one of them, wait for the wound to dry up (it will take around two weeks) and then lay it in the soil, inserting the base of the cutting partially into it and maintaining the soil moist until it puts roots.

Curiosity:

The name “Lemaireocereus pruinosus” is actually a synonym of “Stenocereus pruinosus”. The genus name was choosen after Charles Lemaire, a French botanist specialised in cacti who lived from 1801 to 1871. The species name, instead, “pruinosus”, means “equipped with a pruine”, which is because of its waxy, whitish, subtle layer covering the stem, that has a function of protection from sun rays, pathogens and water loss through evapotranspiration.

Official Web Site:
www.giromagi.com

Italian Blog:
www.giromagicactus.com

Tips:
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